个人博客

http://www.milovetingting.cn

Servlet

1、依赖引入

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<dependencies>
    <!-- https://mvnrepository.com/artifact/junit/junit -->
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.13.2</version>
        <scope>test</scope>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>6.0.3</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/javax.servlet/servlet-api -->
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>servlet-api</artifactId>
        <version>2.5</version>
        <scope>provided</scope>
    </dependency>
    <!-- https://mvnrepository.com/artifact/javax.servlet.jsp/jsp-api -->
    <dependency>
        <groupId>javax.servlet.jsp</groupId>
        <artifactId>jsp-api</artifactId>
        <version>2.2</version>
        <scope>provided</scope>
    </dependency>
</dependencies>

2、创建Servlet

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package com.wangyz.servlet;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class HelloServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String method = req.getParameter("method");
        req.getSession().setAttribute("msg","执行了"+method+"方法");
        req.getRequestDispatcher("/WEB-INF/jsp/hello.jsp").forward(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}

3、注册Servlet

web/WEB-INF/web.xml

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<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    
    <servlet>
        <servlet-name>hello</servlet-name>
        <servlet-class>com.wangyz.servlet.HelloServlet</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>hello</servlet-name>
        <url-pattern>/hello</url-pattern>
    </servlet-mapping>
    
</web-app>

4、新增hello.jsp

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<%--
  Created by IntelliJ IDEA.
  User: wangyz
  Date: 2023/2/20
  Time: 23:28
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Hello</title>
</head>
<body>
${msg}
</body>
</html>

SpringMVC

https://docs.spring.io/spring-framework/docs/6.0.3/reference/html/

1、依赖引入

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<dependencies>
    <!-- https://mvnrepository.com/artifact/junit/junit -->
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.13.2</version>
        <scope>test</scope>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>5.3.25</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/javax.servlet/servlet-api -->
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>servlet-api</artifactId>
        <version>2.5</version>
        <scope>provided</scope>
    </dependency>
    <!-- https://mvnrepository.com/artifact/javax.servlet.jsp/jsp-api -->
    <dependency>
        <groupId>javax.servlet.jsp</groupId>
        <artifactId>jsp-api</artifactId>
        <version>2.2</version>
        <scope>provided</scope>
    </dependency>
</dependencies>

2、配置web.xml

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<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">

    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springmvc-servlet.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

</web-app>

3、Resource目录下创建springmvc-servlet.xml

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<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd">

    <bean class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"/>
    <bean class="org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter"/>
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

    <bean id="/hello" class="com.wangyz.controller.HelloController"/>

</beans>

4、创建Controller

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package com.wangyz.controller;

import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.Controller;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class HelloController implements Controller {

    @Override
    public ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response) throws Exception {
        ModelAndView modelAndView = new ModelAndView();
        modelAndView.addObject("msg", "hello SpringMVC!");
        //WEB-INF/jsp/hello.jsp
        modelAndView.setViewName("hello");
        return modelAndView;
    }
}

5、创建hello.jsp

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<%--
    Created by IntelliJ IDEA.
    User: Meng
        Date: 2023/2/21
            Time: 0:07
                To change this template use File | Settings | File Templates.
                --%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
    <head>
        <title>Hello,SpringMVC</title>
    </head>
    <body>
        ${msg}
    </body>
</html>

可能遇到的问题：访问/hello，提示404

image-20230221001438753

解决方法:

在Project Structure中，选中Project Settings-Artifacts-当前模块，如02-mvc

image-20230221001523584

然后再在WEB-INF目录下,创建文件夹，输入lib,点击添加Library,把所有Library添加进来

image-20230221001609025

重新启动TomCat，就可以正常运行

image-20230221002509072

注解SpringMVC

1、配置web.xml

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<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">

    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springmvc-servlet.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

</web-app>

2、在Resource目录下创建springmvc-servlet.xml

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<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <context:component-scan base-package="com.wangyz.controller"/>
    <mvc:default-servlet-handler/>
    <mvc:annotation-driven/>

    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

</beans>

3、创建Controller

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package com.wangyz.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class HelloController {
    @RequestMapping("/hello")
    public String hello(Model model){
        model.addAttribute("msg","hello SpringMvc");
        return "hello";
    }
}

4、创建jsp

在web/WEB-INF/jsp目录下创建hello.jsp

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<%--
    Created by IntelliJ IDEA.
    User: Meng
        Date: 2023/2/21
            Time: 22:56
                To change this template use File | Settings | File Templates.
                --%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
    <head>
        <title>Title</title>
    </head>
    <body>
        ${msg}
    </body>
</html>

Restful风格

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package com.wangyz.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class RestFulController {

    @RequestMapping("/add/{a}/{b}")
    public String add(@PathVariable int a, @PathVariable int b, Model model){
        model.addAttribute("msg","add:"+(a+b));
        return "add";
    }

    @GetMapping("/method")
    public String requestMethod(Model model){
        model.addAttribute("msg","Get");
        return "method";
    }

    @PostMapping("/method")
    public String requestMethod2(Model model){
        model.addAttribute("msg","Post");
        return "method";
    }
}

重定向和转发

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package com.wangyz.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class RedirectAndForwardController {
    @RequestMapping("/t1")
    public String test1(){
        //转发
        return "test";
    }

    @RequestMapping("/t2")
    public String test2(){
        return "forward:/index.jsp";
    }

    @RequestMapping("/t3")
    public String test3(){
        return "redirect:/index.jsp";
    }
}

参数接收及回显

引入lombok

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<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>1.18.24</version>
    <scope>provided</scope>
</dependency>
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package com.wangyz.controller;

import com.sun.org.glassfish.gmbal.ParameterNames;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import pojo.User;

@Controller
@RequestMapping("/user")
public class UserController {
    @GetMapping("/t1")
    public String t1(String name, Model model){
        //接收传过来的name字段
        //http://localhost:8080/user/t1?name=xx
        model.addAttribute("msg", name);
        return "user";
    }

    @GetMapping("/t2")
    public String t2(@RequestParam("username") String name, Model model){
        //接收传过来的username字段

        //http://localhost:8080/user/t2?username=xx
        model.addAttribute("msg", name);
        return "user";
    }

    @GetMapping("/t3")
    public String t3(User user, Model model){
        //接收传过来的username字段
        //http://localhost:8080/user/t3?id=1&name=xx&address=xxx
        model.addAttribute("msg", user);
        return "user";
    }
}

乱码

web.xml

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<filter>
    <filter-name>encoding</filter-name>
    <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
    <init-param>
        <param-name>encoding</param-name>
        <param-value>utf-8</param-value>
    </init-param>
</filter>
<filter-mapping>
    <filter-name>encoding</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

拦截器

1、基本用法

springmvc-servlet.xml

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<mvc:interceptors>
    <mvc:interceptor>
        <mvc:mapping path="/**"/>
        <bean class="com.wangyz.interceptor.MyInterceptor"/>
    </mvc:interceptor>
</mvc:interceptors>

MyInterceptor.java

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package com.wangyz.interceptor;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class MyInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("处理前==>");
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("处理后==>");
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("清理==>");
    }
}

TestController.java

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package com.wangyz.controller;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class TestController {
    @GetMapping("/t1")
    public String test(){
        System.out.println("TestController==>test()");
        return "ok";
    }
}

2、登录拦截

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<mvc:interceptors>
    <mvc:interceptor>
        <mvc:mapping path="/user/**"/>
        <bean class="com.wangyz.interceptor.UserInterceptor"/>
    </mvc:interceptor>
</mvc:interceptors>

UserInterceptor.java

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package com.wangyz.interceptor;

import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class UserInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        String uri = request.getRequestURI();
        if (uri.equals("/user/home")) {
            String user = (String) request.getSession().getAttribute("user");
            if(user==null||user.isEmpty()){
                request.getRequestDispatcher("/WEB-INF/jsp/login.jsp").forward(request,response);
                return false;
            }
        }
        return true;
    }
}

UserController.java

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package com.wangyz.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.servlet.http.HttpSession;

@Controller
@RequestMapping("/user")
public class UserController {

    @GetMapping("/login")
    public String login(){
        return "login";
    }

    @PostMapping("/doLogin")
    public String doLogin(String name, HttpSession session){
        if(name.equals("admin")){
            session.setAttribute("user",name);
            return "redirect:home";
        }
        else{
            return "redirect:login";
        }
    }

    @GetMapping("/home")
    public String home(){
        return "home";
    }

    @GetMapping("/logout")
    public String logout(HttpSession session){
        session.removeAttribute("user");
        return "redirect:login";
    }

}

上传和下载

1、导入依赖

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<dependency>
    <groupId>commons-fileupload</groupId>
    <artifactId>commons-fileupload</artifactId>
    <version>1.4</version>
</dependency>

2、web.xml

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<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">

    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springmvc-servlet.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

</web-app>

3、springmvc-servlet.xml

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<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <context:component-scan base-package="com.wangyz.controller"/>
    <mvc:default-servlet-handler/>
    <mvc:annotation-driven/>

    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <property name="defaultEncoding" value="utf-8"/>
        <property name="maxUploadSize" value="10485760"/>
        <property name="maxInMemorySize" value="40960"/>
    </bean>

</beans>

4、FileController

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package com.wangyz.controller;

import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.commons.CommonsMultipartFile;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.net.URLEncoder;

@RestController
public class FileController {

    @RequestMapping("/upload")
    public String upload(@RequestParam("file") CommonsMultipartFile file, HttpServletRequest request) throws IOException {
        //获取文件名
        String uploadFileName = file.getOriginalFilename();
        //如果文件名为空
        if ("".equals(uploadFileName)) {
            return "redirect:/index.jsp";
        }
        System.out.println("上传的文件名为:" + uploadFileName);

        //上传路径
        String path = request.getServletContext().getRealPath("/upload");
        File dir = new File(path);
        if (!dir.exists()) {
            dir.mkdirs();
        }
        System.out.println("文件保存路径:" + dir);

        InputStream is = file.getInputStream();
        OutputStream os = new FileOutputStream(new File(dir, uploadFileName));

        int len = 0;
        byte[] buffer = new byte[1024];
        while ((len = is.read(buffer)) != -1) {
            os.write(buffer, 0, len);
            os.flush();
        }
        os.close();
        is.close();
        return "upload success";
    }

    @RequestMapping("/upload2")
    public String upload2(@RequestParam("file") CommonsMultipartFile file, HttpServletRequest request) throws IOException {

        String path = request.getServletContext().getRealPath("/upload");
        File dir = new File(path);
        if (!dir.exists()) {
            dir.mkdirs();
        }
        System.out.println("文件保存路径:" + dir);

        file.transferTo(new File(dir + "/" + file.getOriginalFilename()));

        return "upload success";

    }

    @RequestMapping("/download")
    public String download(HttpServletResponse response, HttpServletRequest request) throws Exception {
        String path = request.getServletContext().getRealPath("/upload");
        String fileName = "积分奖励.docx";

        response.reset();
        response.setCharacterEncoding("UTF-8");
        response.setContentType("multipart/form-data");
        response.setHeader("Content-Disposition", "attachment;fileName=" + URLEncoder.encode(fileName, "UTF-8"));

        File file = new File(path, fileName);
        InputStream is = new FileInputStream(file);
        OutputStream os = response.getOutputStream();

        byte[] buffer = new byte[1024];
        int len = 0;
        while ((len = is.read(buffer)) != -1) {
            os.write(buffer, 0, len);
            os.flush();
        }
        os.close();
        is.close();
        return "download success";
    }
}

5、index.jsp

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<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
    <head>
        <title>首页</title>
    </head>
    <body>
        <form action="${pageContext.request.contextPath}/upload2" enctype="multipart/form-data" method="post">
            <input type="file" name="file">
            <input type="submit" value="upload">
        </form>
        <a href="${pageContext.request.contextPath}/download">下载</a>
    </body>
</html>

SSM

导入依赖

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<dependencies>
    <!--单元测试-->
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.13.2</version>
        <scope>test</scope>
    </dependency>
    <!--数据库驱动-->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>8.0.30</version>
    </dependency>
    <!--数据库连接池-->
    <dependency>
        <groupId>com.mchange</groupId>
        <artifactId>c3p0</artifactId>
        <version>0.9.5.5</version>
    </dependency>
    <!--servlet-->
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>servlet-api</artifactId>
        <version>2.5</version>
    </dependency>
    <!--jsp-->
    <dependency>
        <groupId>javax.servlet.jsp</groupId>
        <artifactId>jsp-api</artifactId>
        <version>2.2</version>
    </dependency>
    <!--jstl-->
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>jstl</artifactId>
        <version>1.2</version>
    </dependency>
    <!--mybatis-->
    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis</artifactId>
        <version>3.5.11</version>
    </dependency>
    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis-spring</artifactId>
        <version>2.1.0</version>
    </dependency>
    <!--spring-->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>5.3.25</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-jdbc -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-jdbc</artifactId>
        <version>5.3.25</version>
    </dependency>
    <!--lombok-->
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <version>1.18.24</version>
    </dependency>
</dependencies>

Mybatis

1、建表

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CREATE TABLE `book` (                                                                                                                                                                                               
    `id` int NOT NULL AUTO_INCREMENT,                                                                                                                                                                                 
    `bookName` varchar(100) NOT NULL,                                                                                                                                                                                 
    `description` varchar(100) NOT NULL,                                                                                                                                                                              
    PRIMARY KEY (`id`)                                                                                                                                                                                                
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8

2、插入测试数据

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INSERT INTO `mybatis`.`book`
            (
                `bookName`,
                `description`)
VALUES (
    'MySQL',
    '从删库到跑路');

3、POJO

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package com.wangyz.pojo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Book {
    private int id;
    private String bookName;
    private String description;
}

4、DAO

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package com.wangyz.dao;

import com.wangyz.pojo.Book;

import java.util.List;

public interface BookMapper {

    int addBook(Book book);

    int deleteBook(int id);

    int updateBook(Book book);

    Book queryBookById(int id);

    List<Book> queryAllBook();

}

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<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "https://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.wangyz.dao.BookMapper">

    <insert id="addBook" parameterType="Book">
        insert into book(bookName,description) values(#{bookName},#{description})
    </insert>

    <delete id="deleteBook" parameterType="int">
        delete from book where id = #{id}
    </delete>

    <update id="updateBook" parameterType="Book">
        update book set bookName=#{bookName},description=#{description} where id = #{id}
    </update>

    <select id="queryBookById" resultType="Book">
        select * from book where id = #{id}
    </select>

    <select id="queryAllBook" resultType="Book">
        select * from book
    </select>

</mapper>

5、Service

BookService.java

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package com.wangyz.service;

import com.wangyz.pojo.Book;

import java.util.List;

public interface BookService {
    int addBook(Book book);

    int deleteBook(int id);

    int updateBook(Book book);

    Book queryBookById(int id);

    List<Book> queryAllBook();
}

BookServiceImpl.java

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package com.wangyz.service;

import com.wangyz.dao.BookMapper;
import com.wangyz.pojo.Book;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class BookServiceImpl implements BookService{

    private BookMapper mapper;

    public void setMapper(BookMapper mapper) {
        this.mapper = mapper;
    }

    @Override
    public int addBook(Book book) {
        return mapper.addBook(book);
    }

    @Override
    public int deleteBook(int id) {
        return mapper.deleteBook(id);
    }

    @Override
    public int updateBook(Book book) {
        return mapper.updateBook(book);
    }

    @Override
    public Book queryBookById(int id) {
        return mapper.queryBookById(id);
    }

    @Override
    public List<Book> queryAllBook() {
        return mapper.queryAllBook();
    }
}

6、配置

db.properties

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jdbc.driver=com.mysql.cj.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/mybatis?useSSL=true&useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
jdbc.username=root
jdbc.password=root

mybatis-config.xml

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<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "https://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <typeAliases>
        <package name="com.wangyz.pojo"/>
    </typeAliases>
    <mappers>
        <mapper class="com.wangyz.dao.BookMapper"/>
    </mappers>
</configuration>

Spring

spring-dao.xml

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<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
                           http://www.springframework.org/schema/beans/spring-beans.xsd
                           http://www.springframework.org/schema/context
                           https://www.springframework.org/schema/context/spring-context.xsd">

    <context:property-placeholder location="classpath:db.properties"/>

    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="${jdbc.driver}"/>
        <property name="jdbcUrl" value="${jdbc.url}"/>
        <property name="user" value="${jdbc.username}"/>
        <property name="password" value="${jdbc.password}"/>

        <property name="maxPoolSize" value="30"/>
        <property name="minPoolSize" value="10"/>
        <property name="autoCommitOnClose" value="false"/>
        <property name="checkoutTimeout" value="10000"/>
        <property name="acquireRetryAttempts" value="3"/>
    </bean>

    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
    </bean>

    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
        <property name="basePackage" value="com.wangyz.dao"/>
    </bean>

</beans>

spring-service.xml

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<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd">

    <context:component-scan base-package="com.wangyz.service"/>

    <bean id="bookServiceImpl"  class="com.wangyz.service.BookServiceImpl">
        <property name="mapper" ref="bookMapper"/>
    </bean>

    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"/>
    </bean>
</beans>

applicationContext.xml

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<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
                           http://www.springframework.org/schema/beans/spring-beans.xsd">

    <import resource="classpath:spring-dao.xml"/>
    <import resource="classpath:spring-service.xml"/>

</beans>

SpringMVC

spring-mvc.xml

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<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
                           http://www.springframework.org/schema/beans/spring-beans.xsd
                           http://www.springframework.org/schema/context
                           https://www.springframework.org/schema/context/spring-context.xsd
                           http://www.springframework.org/schema/mvc
                           https://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <mvc:annotation-driven/>
    <mvc:default-servlet-handler/>
    <context:component-scan base-package="com.wangyz.controller"/>

    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

</beans>

applicationContext.xml

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<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
                           http://www.springframework.org/schema/beans/spring-beans.xsd">

    <import resource="classpath:spring-dao.xml"/>
    <import resource="classpath:spring-service.xml"/>
    <import resource="classpath:spring-mvc.xml"/>

</beans>

web.xml

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<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">

    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:applicationContext.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

    <filter>
        <filter-name>encoding</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>utf-8</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>encoding</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <session-config>
        <session-timeout>15</session-timeout>
    </session-config>

</web-app>

BookController.java

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package com.wangyz.controller;

import com.wangyz.pojo.Book;
import com.wangyz.service.BookService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;

import java.util.List;

@Controller
@RequestMapping("/book")
public class BookController {

    @Autowired
    @Qualifier("bookServiceImpl")
    private BookService bookService;


    @GetMapping("/allBook")
    public String queryAllBook(Model model){
        List<Book> bookList = bookService.queryAllBook();
        model.addAttribute("bookList",bookList);
        return "allBook";
    }

}