JavaWeb_(Spring框架)注解配置

2023-07-19 11:55:04

Spring注解配置

　　a)导包和约束：基本包、aop包+context约束；

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
       xmlns="http://www.springframework.org/schema/beans" 
       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 ">
    
    <!-- 注解开发 -->
    <!-- 开启组件扫描 base-package 扫描该包下以及子包的所有注解   -->
    <context:component-scan base-package="com.Gary.bean"/>    

</beans>

applicationContext_annotation.xml

　　b)将对象注册到容器内；

　　在User2.java中需要用到<bean name="user" class="com.Gary.bean.User">的地方使用@Component("user")

　　@Controller()　　　　1对应web层

　　@Service("user")　　对应service

　　@Repository()　　　对应dao层

package com.Gary.bean;

import org.springframework.stereotype.Component;

//<bean name="user" class="com.Gary.bean.User">
@Component("user")
public class User2 {

    private Integer u_id;
    private String u_username;
    private String u_password;


    //加入宠物字段
    private Pet u_pet;
    
    @Override
    public String toString() {
        return "User [u_id=" + u_id + ", u_username=" + u_username + ", u_password=" + u_password + ", u_pet=" + u_pet
                + "]";
    }
    public Pet getU_pet() {
        return u_pet;
    }
    public void setU_pet(Pet u_pet) {
        this.u_pet = u_pet;
    }
    
    public User2() {
        System.out.println("默认使用 User2 对象空参构造方法");
    }
    
    public Integer getU_id() {
        return u_id;
    }
    public void setU_id(Integer u_id) {
        this.u_id = u_id;
    }
    public String getU_username() {
        return u_username;
    }
    public void setU_username(String u_username) {
        this.u_username = u_username;
    }
    public String getU_password() {
        return u_password;
    }
    public void setU_password(String u_password) {
        this.u_password = u_password;
    }
    

    
}

User2.java

package com.Gary.test;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.Gary.bean.User2;

public class Test_Annotation {

    //Spring是一个容器，它将帮助我们管理对象
    @Test
    public void Test2() {
    
        ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext_annotation.xml");
        
        User2 u2 = (User2) ac.getBean("user");
        
        System.out.println(u2);
        
    }
    
    
}

Test_Annotation.java

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
       xmlns="http://www.springframework.org/schema/beans" 
       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 ">
    
    <!-- 注解开发 -->
    <!-- 开启组件扫描 base-package 扫描该包下以及子包的所有注解   -->
    <context:component-scan base-package="com.Gary.bean"/>    

</beans>

applicationContext_annotation.xml

　　c)用注解配置Scope属性；

　　在需要加Scope属性的bean实体层下使用

　　@Service("user")
　　//@Scope默认是单例的
　　@Scope(scopeName="prototype")

package com.Gary.bean;

import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Service;

//<bean name="user" class="com.Gary.bean.User">
//@Component("user")
@Service("user")
//@Scope默认是单例的
@Scope(scopeName="prototype")
public class User2 {

    private Integer u_id;
    private String u_username;
    private String u_password;


    //加入宠物字段
    private Pet u_pet;
    
    @Override
    public String toString() {
        return "User [u_id=" + u_id + ", u_username=" + u_username + ", u_password=" + u_password + ", u_pet=" + u_pet
                + "]";
    }
    public Pet getU_pet() {
        return u_pet;
    }
    public void setU_pet(Pet u_pet) {
        this.u_pet = u_pet;
    }
    
    public User2() {
        System.out.println("默认使用 User2 对象空参构造方法");
    }
    
    public Integer getU_id() {
        return u_id;
    }
    public void setU_id(Integer u_id) {
        this.u_id = u_id;
    }
    public String getU_username() {
        return u_username;
    }
    public void setU_username(String u_username) {
        this.u_username = u_username;
    }
    public String getU_password() {
        return u_password;
    }
    public void setU_password(String u_password) {
        this.u_password = u_password;
    }
    

    
}

User2.java

package com.Gary.test;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Scope;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.Gary.bean.User2;

public class Test_Annotation {

    //Spring是一个容器，它将帮助我们管理对象
    @Test
    public void Test2() {
    
        ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext_annotation.xml");
        
        User2 u1 = (User2) ac.getBean("user");
        User2 u2 = (User2) ac.getBean("user");
        //@Scope(scopeName="prototype")多例的
        
        System.out.println(u1==u2);
        
    }
    
    
}

Test_Annotation.java

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
       xmlns="http://www.springframework.org/schema/beans" 
       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 ">
    
    <!-- 注解开发 -->
    <!-- 开启组件扫描 base-package 扫描该包下以及子包的所有注解   -->
    <context:component-scan base-package="com.Gary.bean"/>    

</beans>

applicationContent_annotation.xml

　　d)注解配置init-method与destroy-method；

    //在构造方法后调用
    @PostConstruct()
    public void userInit() {
        System.out.println("构造方法");
    }
    
    //在销毁方法前调用
    @PreDestroy()
    public void userDestory() {
        System.out.println("销毁方法");
    }

package com.Gary.bean;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;

import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Service;

//<bean name="user" class="com.Gary.bean.User">
//@Component("user")
@Service("user")
public class User2 {

    private Integer u_id;
    private String u_username;
    private String u_password;


    //加入宠物字段
    private Pet u_pet;
    
    @Override
    public String toString() {
        return "User [u_id=" + u_id + ", u_username=" + u_username + ", u_password=" + u_password + ", u_pet=" + u_pet
                + "]";
    }
    public Pet getU_pet() {
        return u_pet;
    }
    public void setU_pet(Pet u_pet) {
        this.u_pet = u_pet;
    }
    
    public User2() {
        System.out.println("默认使用 User2 对象空参构造方法");
    }
    
    public Integer getU_id() {
        return u_id;
    }
    public void setU_id(Integer u_id) {
        this.u_id = u_id;
    }
    public String getU_username() {
        return u_username;
    }
    public void setU_username(String u_username) {
        this.u_username = u_username;
    }
    public String getU_password() {
        return u_password;
    }
    public void setU_password(String u_password) {
        this.u_password = u_password;
    }
    
    //在构造方法后调用
    @PostConstruct()
    public void userInit() {
        System.out.println("构造方法");
    }
    
    //在销毁方法前调用
    @PreDestroy()
    public void userDestory() {
        System.out.println("销毁方法");
    }
    

    
}

User2.java

package com.Gary.test;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Scope;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.Gary.bean.User2;

public class Test_Annotation {

    //Spring是一个容器，它将帮助我们管理对象
    @Test
    public void Test2() {
    
        ClassPathXmlApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext_annotation.xml");
        
        User2 u1 = (User2) ac.getBean("user");
        
        ac.close();
        
    }
    
    
}

Test_Annotation.java

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
       xmlns="http://www.springframework.org/schema/beans" 
       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 ">
    
    <!-- 注解开发 -->
    <!-- 开启组件扫描 base-package 扫描该包下以及子包的所有注解   -->
    <context:component-scan base-package="com.Gary.bean"/>    

</beans>

applicationContext_annotation.xml

　　e)注解配置属性注入，值类型与引用类型；

　　属性、值注入

    @Value(value="111111111")
    private Integer u_id;
    @Value(value="ggggggary")
    private String u_username;
    private String u_password;

package com.Gary.bean;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Service;

//<bean name="user" class="com.Gary.bean.User">
//@Component("user")
@Service("user")
public class User2 {

    @Value(value="111111111")
    private Integer u_id;
    @Value(value="ggggggary")
    private String u_username;
    private String u_password;


    //加入宠物字段
    private Pet u_pet;
    
    @Override
    public String toString() {
        return "User [u_id=" + u_id + ", u_username=" + u_username + ", u_password=" + u_password + ", u_pet=" + u_pet
                + "]";
    }
    public Pet getU_pet() {
        return u_pet;
    }
    public void setU_pet(Pet u_pet) {
        this.u_pet = u_pet;
    }
    
    public User2() {
        System.out.println("默认使用 User2 对象空参构造方法");
    }
    
    public Integer getU_id() {
        return u_id;
    }
    public void setU_id(Integer u_id) {
        this.u_id = u_id;
    }
    public String getU_username() {
        return u_username;
    }
    public void setU_username(String u_username) {
        this.u_username = u_username;
    }
    public String getU_password() {
        return u_password;
    }
    public void setU_password(String u_password) {
        this.u_password = u_password;
    }
    
    //在构造方法后调用
    @PostConstruct()
    public void userInit() {
        System.out.println("构造方法");
    }
    
    //在销毁方法前调用
    @PreDestroy()
    public void userDestory() {
        System.out.println("销毁方法");
    }
    

    
}

User2.java

package com.Gary.test;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Scope;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.Gary.bean.User2;

public class Test_Annotation {

    //Spring是一个容器，它将帮助我们管理对象
    @Test
    public void Test2() {
    
        ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext_annotation.xml");
        
        User2 u1 = (User2) ac.getBean("user");

        System.out.println(u1);
        
    }
    
    
}

Test_Annotation.java

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
       xmlns="http://www.springframework.org/schema/beans" 
       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 ">
    
    <!-- 注解开发 -->
    <!-- 开启组件扫描 base-package 扫描该包下以及子包的所有注解   -->
    <context:component-scan base-package="com.Gary.bean"/>    

</beans>

applicationContext_annotation.xml

　　也可以在方法上加注释

    @Value("233333333")
    public void setU_password(String u_password) {
        this.u_password = u_password;
    }

　　Spring能在private私有成员上通过@Value()去赋值，使用了暴力反射去注入的，推荐使用在set()方法上注入属性

　　引用类型注入

　　给宠物起名为cat，并给宠物类型和颜色通过@Value赋值

@Component("cat")
public class Pet {

    @Value("猫猫猫")
    public void setPetType(String petType) {
        this.petType = petType;
    }

    
    @Value("灰色")
    public void setColor(String color) {
        this.color = color;
    }

package com.Gary.bean;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Component("cat")
public class Pet {

    //宠物类型  猫  狗
    private String petType;
    //宠物颜色
    private String color;
    
    @Override
    public String toString() {
        return "Pet [petType=" + petType + ", color=" + color + "]";
    }
    public String getPetType() {
        return petType;
    }
    
    @Value("猫猫猫")
    public void setPetType(String petType) {
        this.petType = petType;
    }

    
    @Value("灰色")
    public void setColor(String color) {
        this.color = color;
    }
    
    public String getColor() {
        return color;
    }
    
}

Pet.java

　　在User.java上使用@Autowired()自动装配

    //使用自动装配，加入宠物字段
    @Autowired
    private Pet u_pet;

　　第一种：用@Autowired()代替，缺点：问题：如果匹配到多个类型一致的对象，将无法注入到具体哪个对象

　　为了解决这个确定

　　第二种：用@Qualifier("userService")

　　第三者@Resource(name="userService")

package com.Gary.bean;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Service;

//<bean name="user" class="com.Gary.bean.User">
//@Component("user")
@Service("user")
public class User2 {

    @Value(value="111111111")
    private Integer u_id;
    @Value(value="ggggggary")
    private String u_username;
    private String u_password;


    //使用自动装配，加入宠物字段
    @Autowired
    private Pet u_pet;
    
    @Override
    public String toString() {
        return "User [u_id=" + u_id + ", u_username=" + u_username + ", u_password=" + u_password + ", u_pet=" + u_pet
                + "]";
    }
    public Pet getU_pet() {
        return u_pet;
    }
    public void setU_pet(Pet u_pet) {
        this.u_pet = u_pet;
    }
    
    public User2() {
        System.out.println("默认使用 User2 对象空参构造方法");
    }
    
    public Integer getU_id() {
        return u_id;
    }
    public void setU_id(Integer u_id) {
        this.u_id = u_id;
    }
    public String getU_username() {
        return u_username;
    }
    public void setU_username(String u_username) {
        this.u_username = u_username;
    }
    public String getU_password() {
        return u_password;
    }
    
    @Value("233333333")
    public void setU_password(String u_password) {
        this.u_password = u_password;
    }
    
    //在构造方法后调用
    @PostConstruct()
    public void userInit() {
        System.out.println("构造方法");
    }
    
    //在销毁方法前调用
    @PreDestroy()
    public void userDestory() {
        System.out.println("销毁方法");
    }
    

    
}

User2.java

package com.Gary.bean;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Service;

//<bean name="user" class="com.Gary.bean.User">
//@Component("user")
@Service("user")
public class User2 {

    @Value(value="111111111")
    private Integer u_id;
    @Value(value="ggggggary")
    private String u_username;
    private String u_password;


    //使用自动装配，加入宠物字段
    @Autowired
    private Pet u_pet;
    
    @Override
    public String toString() {
        return "User [u_id=" + u_id + ", u_username=" + u_username + ", u_password=" + u_password + ", u_pet=" + u_pet
                + "]";
    }
    public Pet getU_pet() {
        return u_pet;
    }
    public void setU_pet(Pet u_pet) {
        this.u_pet = u_pet;
    }
    
    public User2() {
        System.out.println("默认使用 User2 对象空参构造方法");
    }
    
    public Integer getU_id() {
        return u_id;
    }
    public void setU_id(Integer u_id) {
        this.u_id = u_id;
    }
    public String getU_username() {
        return u_username;
    }
    public void setU_username(String u_username) {
        this.u_username = u_username;
    }
    public String getU_password() {
        return u_password;
    }
    
    @Value("233333333")
    public void setU_password(String u_password) {
        this.u_password = u_password;
    }
    
    //在构造方法后调用
    @PostConstruct()
    public void userInit() {
        System.out.println("构造方法");
    }
    
    //在销毁方法前调用
    @PreDestroy()
    public void userDestory() {
        System.out.println("销毁方法");
    }
    

    
}

User2.java

package com.Gary.bean;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Component("cat")
public class Pet {

    //宠物类型  猫  狗
    private String petType;
    //宠物颜色
    private String color;
    
    @Override
    public String toString() {
        return "Pet [petType=" + petType + ", color=" + color + "]";
    }
    public String getPetType() {
        return petType;
    }
    
    @Value("猫猫猫")
    public void setPetType(String petType) {
        this.petType = petType;
    }

    
    @Value("灰色")
    public void setColor(String color) {
        this.color = color;
    }
    
    public String getColor() {
        return color;
    }
    
}

Pet.java

package com.Gary.test;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Scope;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.Gary.bean.User2;

public class Test_Annotation {

    //Spring是一个容器，它将帮助我们管理对象
    @Test
    public void Test2() {
    
        ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext_annotation.xml");
        
        User2 u1 = (User2) ac.getBean("user");

        System.out.println(u1);
        
    }
    
    
}

Test_Annotation.java

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
       xmlns="http://www.springframework.org/schema/beans" 
       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 ">
    
    <!-- 注解开发 -->
    <!-- 开启组件扫描 base-package 扫描该包下以及子包的所有注解   -->
    <context:component-scan base-package="com.Gary.bean"/>    

</beans>

applicationContext_annotation.xml

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