Spring使用入门

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Spring Framework

基础环境搭建

1、选择Maven项目，然后点击Next

2、完善信息后点击Finish

3、删除项目根目录下的src文件夹

4、引入Spring相关依赖

<dependencies>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-core -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>5.3.25</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-beans -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>5.3.25</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.3.25</version>
        </dependency>
    </dependencies>

Spring不同版本对应的JDK版本要求不一样

Spring Framework 6.0.x: JDK 17-21 (for native images: JDK 17-19)
Spring Framework 5.3.x: JDK 8-19

5、新建Module,选择Maven类型，点击Next,然后完善相关信息。

传统的方式

普通对象创建

public class User {

    private String name;

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public String toString() {
        return "User{" +
                "name='" + name + '\'' +
                '}';
    }
}

public class MyTest {
    public static void main(String[] args) {

        User user = new User();
        user.setName("zs");
        System.out.println(user.toString());
      
    }
}

运行后的输出结果：

User{name=’zs’}

Dao调用

public interface IDao {
    void getUser();
}

public class MySqlDaoImpl implements IDao {
    @Override
    public void getUser() {
        System.out.println("MySqlDaoImpl-->getUser");
    }
}

public class OracleDaoImpl implements IDao {
    @Override
    public void getUser() {
        System.out.println("OracleDaoImpl-->getUser");
    }
}

public interface IService {
    void getUser();
}

public class ServiceImpl implements IService {

    IDao dao = new MySqlDaoImpl();

    @Override
    public void getUser() {
        dao.getUser();
    }
}

public class MyTest {
    public static void main(String[] args) {

        IService service = new ServiceImpl();
        service.getUser();
				System.out.println(user.toString());
    }
}

运行后的输出结果

MySqlDaoImpl–>getUser

IOC调用方式

普通对象创建

1、xml配置

在resources目录下新建bean.xml文件

<?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">

    <bean id="user" class="com.wangyz.ioc.pojo.User">
        <property name="name" value="hello"/>
    </bean>
    
    <!--    构造函数，方式一-->
    <bean id="user" class="com.wangyz.ioc.pojo.User">
        <constructor-arg index="0" value="hi"/>
    </bean>

	<!--    构造函数，方式二 不建议使用-->
    <bean id="user" class="com.wangyz.ioc.pojo.User">
        <constructor-arg type="java.lang.String" value="hey"/>
    </bean>

	<!--    构造函数，方式三-->
    <bean id="user" class="com.wangyz.ioc.pojo.User">
           <constructor-arg name="name" value="haha"/>
    </bean>

</beans>

2、调用

public class MyTest {
    public static void main(String[] args) {

        //创建上下文对象,读取配置文件,bean工厂
        ApplicationContext context = new ClassPathXmlApplicationContext("bean.xml");
        //创建Bean
        User user = (User) context.getBean("user");
        System.out.println(user.toString());

    }
}

Dao调用

1、xml配置

在resources目录下新建bean.xml文件

<?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">

    <bean id="mysqlDao" class="com.wangyz.ioc.dao.MySqlDaoImpl"/>

    <bean id="oracleDao" class="com.wangyz.ioc.dao.OracleDaoImpl"/>

    <bean id="service" class="com.wangyz.ioc.service.ServiceImpl">
        <property name="dao" ref="oracleDao"/>
    </bean>

</beans>

2、调用

public class MyTest {
    public static void main(String[] args) {

        //创建上下文对象,读取配置文件,bean工厂
        ApplicationContext context = new ClassPathXmlApplicationContext("bean.xml");
        //创建service
        IService service = (IService) context.getBean("service");
        service.getUser();

    }
}

别名

<!-- 别名-->
<alias name="user" alias="userNew"/>

<!--name就是别名，可以有多个别名，通过,或者空格等分隔， -->
<bean id="user" class="com.wangyz.ioc.pojo.User" name="u1,u2">
    <property name="name" value="hello"/>
</bean>

import

<import resource="bean.xml"/>

可通过import导入其它xml

依赖注入

1、pojo定义

public class Address {
    private String province;
    private String city;
    private String district;
    private String street;

    public void setProvince(String province) {
        this.province = province;
    }

    public void setCity(String city) {
        this.city = city;
    }

    public void setDistrict(String district) {
        this.district = district;
    }

    public void setStreet(String street) {
        this.street = street;
    }

    @Override
    public String toString() {
        return "Address{" +
            "province='" + province + '\'' +
            ", city='" + city + '\'' +
            ", district='" + district + '\'' +
            ", street='" + street + '\'' +
            '}';
    }
}

public class Student {
    private String name;
    private int age;
    private String[] hobbies;
    private Address address;

    public void setName(String name) {
        this.name = name;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public void setHobbies(String[] hobbies) {
        this.hobbies = hobbies;
    }

    public void setAddress(Address address) {
        this.address = address;
    }

    @Override
    public String toString() {
        return "Student{" +
            "name='" + name + '\'' +
            ", age=" + age +
            ", hobbies=" + Arrays.toString(hobbies) +
            ", address=" + address +
            '}';
    }
}

2、xml

<?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">

    <bean name="address" class="com.wangyz.di.pojo.Address">
        <property name="province" value="广东省"/>
        <property name="city" value="深圳市"/>
        <property name="district" value="南山区"/>
        <property name="street" value="xx街道"/>
    </bean>

    <bean name="student" class="com.wangyz.di.pojo.Student">
        <property name="address" ref="address"/>
        <property name="name" value="张三"/>
        <property name="age" value="10"/>
        <property name="hobbies">
            <array>
                <value>唱</value>
                <value>跳</value>
                <value>Rap</value>
                <value>打篮球</value>
            </array>
        </property>

        </beans>

P命名空间

用于属性

public class User {
    private String name;
    private int age;

    public void setName(String name) {
        this.name = name;
    }

    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return "User{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}

增加p命名空间声明xmlns:p="http://www.springframework.org/schema/p"

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:p="http://www.springframework.org/schema/p"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="user" class="com.wangyz.di.pojo.User" p:name="张三" p:age="10"/>
    
</beans>

C命名空间

用于构造函数

public class User {
    private String name;
    private int age;

    public void setName(String name) {
        this.name = name;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public User(String name, int age) {
        this.name = name;
        this.age = age;
    }


    @Override
    public String toString() {
        return "User{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}

增加c命名空间声明

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:c="http://www.springframework.org/schema/c"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="user" class="com.wangyz.di.pojo.User" c:name="李四" c:age="20"/>

</beans>

Autowired

1、Bean定义

public class Cat {
    public void run(){
        System.out.println("Cat run");
    }
}

public class Dog {
    public void run(){
        System.out.println("Dog run");
    }
}

public class Person {
    private Dog dog;
    private Cat cat;
    private String name;

    public Dog getDog() {
        return dog;
    }

    public void setDog(Dog dog) {
        this.dog = dog;
    }

    public Cat getCat() {
        return cat;
    }

    public void setCat(Cat cat) {
        this.cat = cat;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

2、xml

<?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">

    <bean name="dog" class="com.wangyz.autowired.pojo.Dog"/>

    <bean name="cat" class="com.wangyz.autowired.pojo.Cat"/>

    <bean name="person" class="com.wangyz.autowired.pojo.Person">
        <property name="name" value="张三"/>
        <property name="dog" ref="dog"/>
        <property name="cat" ref="cat"/>
    </bean>

</beans>

3、测试

public class MyTest {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
        Person person = context.getBean("person", Person.class);
        person.getDog().run();
        person.getCat().run();
    }
}

注解实现Autowired

在属性上直接加上@Autowired注解

public class Person {

    @Autowired
    private Dog dog;
    @Autowired
    private Cat cat;
    private String name;

    public Dog getDog() {
        return dog;
    }

    public void setDog(Dog dog) {
        this.dog = dog;
    }

    public Cat getCat() {
        return cat;
    }

    public void setCat(Cat cat) {
        this.cat = cat;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

<?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 http://www.springframework.org/schema/context/spring-context.xsd">

    <!--开启注解支持-->
    <context:annotation-config/>

    <bean name="dog" class="com.wangyz.autowired.pojo.Dog"/>

    <bean name="cat" class="com.wangyz.autowired.pojo.Cat"/>

    <bean name="person" class="com.wangyz.autowired.pojo.Person"/>

</beans>

@Autowired通过byType类型查找，如果存在多个相同类型的属性，需要@Qualifer注解来指定。@Resource先通过byName查找,再通过byType查找。

Spring 注解

配置xml

<?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 http://www.springframework.org/schema/context/spring-context.xsd">

    <!--要扫描的包-->
    <context:component-scan base-package="com.wangyz.anno.pojo"/>

    <context:annotation-config/>

</beans>

@Component
public class User {
    @Value("李四")
    private String name;

    @Override
    public String toString() {
        return "User{" +
                "name='" + name + '\'' +
                '}';
    }
}

Config方式的注解

public class User {
    private String name;

    @Override
    public String toString() {
        return "User{" +
                "name='" + name + '\'' +
                '}';
    }
}

@Configuration
public class Config {

    @Bean
    public User getUser() {
        return new User();
    }
}

public class MyTest {
    public static void main(String[] args) {
        ApplicationContext context = new AnnotationConfigApplicationContext();
        User user = (User) context.getBean("user");
        System.out.println(user.toString());
    }
}

静态代理

public interface IRent {
    void rent();
}

public class Host implements IRent{
    @Override
    public void rent() {
        System.out.println("出租房子");
    }
}

public class Client implements IRent{
    @Override
    public void rent() {
        System.out.println("租房");
    }
}

public class Proxy implements IRent {

    private Host host;

    public void setHost(Host host) {
        this.host = host;
    }

    @Override
    public void rent() {
        beforeRent();
        host.rent();
        afterRent();
    }

    private void beforeRent() {
        System.out.println("beforeRent");
    }

    private void afterRent() {
        System.out.println("afterRent");
    }
}

public class MyTest {
    public static void main(String[] args) {
        Host host = new Host();
        Proxy proxy = new Proxy();
        proxy.setHost(host);
        Client client = new Client();
        client.rent();
        proxy.rent();
    }
}

动态代理

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

public class DynamicProxy implements InvocationHandler {

    private Object target;

    public void setTarget(Object target) {
        this.target = target;
    }

    public Object getProxy() {
        return Proxy.newProxyInstance(this.getClass().getClassLoader(), target.getClass().getInterfaces(), this);
    }

    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        beforeRent();
        Object result =  method.invoke(target, args);
        afterRent();
        return  result;
    }

    private void beforeRent() {
        System.out.println("beforeRent");
    }

    private void afterRent() {
        System.out.println("afterRent");
    }
}

DynamicProxy proxy = new DynamicProxy();
Host host = new Host();
proxy.setTarget(host);
IRent rent = (IRent) proxy.getProxy();
rent.rent();

AOP

配置依赖

<!-- https://mvnrepository.com/artifact/org.aspectj/aspectjweaver -->
<dependency>
    <groupId>org.aspectj</groupId>
    <artifactId>aspectjweaver</artifactId>
    <version>1.9.19</version>
</dependency>

Spring接口

import org.springframework.aop.MethodBeforeAdvice;

import java.lang.reflect.Method;

public class BeforeLog implements MethodBeforeAdvice {
    @Override
    public void before(Method method, Object[] args, Object target) throws Throwable {
        System.out.println(target.getClass().getName() + ":" + method.getName() + "执行前");
    }
}

import org.springframework.aop.AfterReturningAdvice;

import java.lang.reflect.Method;

public class AfterLog implements AfterReturningAdvice {
    @Override
    public void afterReturning(Object returnValue, Method method, Object[] args, Object target) throws Throwable {
        System.out.println(target.getClass().getName() + ":" + method.getName() + "执行后,返回结果:" + returnValue);
    }
}

public class MyTest {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        IUserService service = context.getBean("userService", IUserService.class);
        service.add();
    }
}

<?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:aop="http://www.springframework.org/schema/aop"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
                           http://www.springframework.org/schema/beans/spring-beans.xsd
                           http://www.springframework.org/schema/aop
                           https://www.springframework.org/aop/spring-aop.xsd">
    <bean id="userService" class="com.wangyz.aop.service.UserServiceImpl"/>
    <bean id="beforeLog" class="com.wangyz.aop.log.BeforeLog"/>
    <bean id="afterLog" class="com.wangyz.aop.log.AfterLog"/>

    <aop:config>
        <aop:pointcut id="pointCut" expression="execution(* com.wangyz.aop.service.UserServiceImpl.* (..))"/>
        <aop:advisor advice-ref="beforeLog" pointcut-ref="pointCut"/>
        <aop:advisor advice-ref="afterLog" pointcut-ref="pointCut"/>
    </aop:config>
</beans>

自定义切入点

public class CustomPointCut {

    public void before() {
        System.out.println("before");
    }

    public void after() {
        System.out.println("after");
    }
}

<?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:aop="http://www.springframework.org/schema/aop"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
                           http://www.springframework.org/schema/beans/spring-beans.xsd
                           http://www.springframework.org/schema/aop
                           https://www.springframework.org/aop/spring-aop.xsd">

    <bean id="userService" class="com.wangyz.aop.service.UserServiceImpl"/>
    <bean id="beforeLog" class="com.wangyz.aop.log.BeforeLog"/>
    <bean id="afterLog" class="com.wangyz.aop.log.AfterLog"/>

    <bean id="pointCut" class="com.wangyz.aop.custom.CustomPointCut"/>

    <aop:config>
        <aop:aspect ref="pointCut">
            <aop:pointcut id="point" expression="execution(* com.wangyz.aop.service.UserServiceImpl.* (..))"/>
            <aop:before method="before" pointcut-ref="point"/>
            <aop:after method="after" pointcut-ref="point"/>
        </aop:aspect>

    </aop:config>

</beans>

注解

import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;

@Aspect
public class AnnotationPointCut {

    @Before("execution(* com.wangyz.aop.service.UserServiceImpl.* (..))")
    public void before() {
        System.out.println("before");
    }

    @After("execution(* com.wangyz.aop.service.UserServiceImpl.* (..))")
    public void after() {
        System.out.println("after");
    }

    @Around("execution(* com.wangyz.aop.service.UserServiceImpl.* (..))")
    public void around(ProceedingJoinPoint proceedingJoinPoint) throws  Throwable{
        System.out.println("环绕前");
        Object proceed = proceedingJoinPoint.proceed();
        System.out.println("环绕后");
    }
}

<?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:aop="http://www.springframework.org/schema/aop"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
                           http://www.springframework.org/schema/beans/spring-beans.xsd
                           http://www.springframework.org/schema/aop
                           https://www.springframework.org/aop/spring-aop.xsd">

    <bean id="userService" class="com.wangyz.aop.service.UserServiceImpl"/>
    <bean id="beforeLog" class="com.wangyz.aop.log.BeforeLog"/>
    <bean id="afterLog" class="com.wangyz.aop.log.AfterLog"/>

    <bean id="annotationPointCut" class="com.wangyz.aop.anno.AnnotationPointCut"/>
    <aop:aspectj-autoproxy/>

</beans>