IoC入门案例制作步骤

• 1.spring坐标pom.xml文件
• 2.编写业务层接口与实现类
• 3.编写持久层接口与实现类
• 4.建立spring配置文件
• 5.data.properties资源
• 6.TestUser测试类通过spring获取资源（Service实例）

案例目录结构

1.pom.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com</groupId>
    <artifactId>java-01</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.1.9.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.16</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
    </dependencies>
</project>

2.编写业务层与表现层（模拟）接口与实现类

package com.limei.service;

public interface UserService {
    public void save();
}

package com.limei.service.impl;


import com.limei.dao.UserDao;
import com.limei.service.UserService;

public class UserServiceImpl implements UserService {
    public UserServiceImpl() {
    }

    private UserDao userDao;
    private int num;
    public void setNum(int num) {
        this.num = num;
    }

    //1.对需要进行注入的变量加set方法
    public void setUserDao(UserDao userDao) {
        this.userDao = userDao;
    }
    public void save() {
        System.out.println("user service running..."+num);
        userDao.save();
    }
}

3.编写持久层层接口与实现类

package com.limei.dao;

public interface UserDao {
    public void save();
}

package com.limei.dao.impl;

import com.limei.dao.UserDao;

public class UserDaoImpl implements UserDao{

    private String userName;
    private String password;
    private int num;
    private String name;

    public UserDaoImpl() {
    }


    public void setNum(int num) {
        this.num = num;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public void setPassword(String password) {
        this.password = password;
    }
    public void setName(String name) {
        this.name = name;
    }
    public void save(){
        System.out.println("user dao running..."+userName+" "+password+" "+num
        );
    }
}

4.建立spring配置文件applicationContext.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:p="http://www.springframework.org/schema/p"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        https://www.springframework.org/schema/context/spring-context.xsd">

    <!--1.加载context命名空间的支持-->
    <!--xmlns:context="http://www.springframework.org/schema/context"-->
    <!--2.加载配置文件-->
    <context:property-placeholder location="classpath:data.properties" />
    <!--2.将要注入的资源声明为bean-->
    <bean id="userDao" class="com.limei.dao.impl.UserDaoImpl" >
        <property name="userName" value="${username1}"/>
        <property name="password" value="${pwd}"/>
        <!--<property name="name" value="${name1}"/>-->
        <property name="num" value="99999999"></property>
    </bean>
    <!--<bean id="bookDao" class="com.limei.dao.impl.BookDaoImpl"/>-->
    <bean id="userService" class="com.limei.service.impl.UserServiceImpl">
        <!--3.ref为引用类型，name为UserServiceImpl里的setUserDao-->
        <property name="userDao" ref="userDao"/>
        <property name="num" value="1234"></property>
    </bean>

</beans>

5.data.properties资源

username1=root123
pwd=123

6.TestUser测试类通过spring获取资源（Service实例）

import com.limei.service.UserService;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class TestUser {

    @Test
    public void save(){
        ApplicationContext ctx = new ClassPathXmlApplicationContext ("applicationContext.xml");
//        ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext-user.xml","applicationContext-book.xml");
        UserService userService = (UserService) ctx.getBean("userService");
        userService.save();

    }
}