Spring框架——基于XML/注解开发

IoC的实现方式有两种：XML配置文件、基于注解。

MVC开发模式：

　　Controller层

　　Service层

　　Repository层

　　Controller层调用Service，Service调用Repository

基于XML配置文件方式

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 id="userController" class="com.sunjian.controller.UserController">
        <property name="userService" ref="userService"></property>
    </bean>

    <bean id="userService" class="com.sunjian.service.impl.UserServiceImpl">
        <property name="userRepository" ref="userRepository"></property>
    </bean>

    <bean id="userRepository" class="com.sunjian.repository.impl.UserRepositoryImpl"></bean>
</beans>

entity

package com.sunjian.entity;

public class User2 {
    private Integer id;
    private String name;

    public User2(int id, String name) {
        this.id = id;
        this.name = name;
    }

    public User2(Integer id, String name) {
        this.id = id;
        this.name = name;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

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

    @Override
    public String toString() {
        return "User2{" +
                "id=" + id +
                ", name='" + name + '\'' +
                '}';
    }
}

repository

package com.sunjian.repository;

import com.sunjian.entity.User2;

/**
 * @author sunjian
 * @date 2020/3/14 15:44
 */
public interface UserRepository {
    public User2 findUserById(Integer id);
}

repositoryImpl

package com.sunjian.repository.impl;

import com.sunjian.entity.User2;
import com.sunjian.repository.UserRepository;

import java.util.HashMap;
import java.util.Map;

/**
 * @author sunjian
 * @date 2020/3/14 15:45
 */
public class UserRepositoryImpl implements UserRepository {
    private static Map<Integer, User2> userMap;

    static {
        userMap = new HashMap<Integer, User2>();
        userMap.put(1, new User2(1, "张三"));
        userMap.put(2, new User2(2, "李四"));
    }

    public User2 findUserById(Integer id) {
        return userMap.get(id);
    }
}

service

package com.sunjian.service;

import com.sunjian.entity.User2;

/**
 * @author sunjian
 * @date 2020/3/14 15:36
 */
public interface UserService {
    User2 findUserBuId(Integer id);
}

serviceImpl

package com.sunjian.service.impl;

import com.sunjian.entity.User2;
import com.sunjian.repository.UserRepository;
import com.sunjian.repository.impl.UserRepositoryImpl;
import com.sunjian.service.UserService;

/**
 * @author sunjian
 * @date 2020/3/14 15:38
 */
public class UserServiceImpl implements UserService {
    private UserRepository userRepository;

    public void setUserRepository(UserRepository userRepository) {
        this.userRepository = userRepository;
    }

    public User2 findUserBuId(Integer id) {
        return userRepository.findUserById(id);
    }

    public void setUserRepository(UserRepositoryImpl userRepository) {
    }
}

controller

package com.sunjian.controller;

import com.sunjian.entity.User2;
import com.sunjian.service.UserService;
import com.sunjian.service.impl.UserServiceImpl;

/**
 * @author sunjian
 * @date 2020/3/14 15:56
 */
public class UserController {

    private UserService userService;

    public void setUserService(UserService userService) {
        this.userService = userService;
    }

    public User2 findUserById(Integer id){
        return userService.findUserBuId(id);
    }
}

test class

package com.sunjian.test;

import com.sunjian.controller.UserController;
import com.sunjian.entity.User2;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

/**
 * @author sunjian
 * @date 2020/3/14 16:03
 */
public class Test4 {
    public static void main(String[] args) {
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring2.xml");
        UserController userController = (UserController) applicationContext.getBean("userController");
        User2 user = userController.findUserById(2);
        System.out.println(user);
    }
}

User2{id=2, name='李四'}

基于注解方式

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 https://www.springframework.org/schema/context/spring-context.xsd">

    <!-- 将类扫描到IoC容器中 -->
    <context:component-scan base-package="com.sunjian"></context:component-scan>

</beans>