spring 入门例子--spring注入方式（设值注入&构造器注入）

工具准备

- myeclipse（10.7.1）

创建一个java web项目并添加spiing支持（或打开一个项目）

实现的业务逻辑


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  • 上图中InjectionServiceImpl有InjectionDAO的变量，当没有主动去创建，而是通过配置文件配置，让spring帮我们去完成
  • 目标1通过xml文件配置实现设置注入

工程目录结构展示

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为项目添加spring环境支持


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此时myeclipse自动为我们引入spring的jar包
并自动创建applicationContext.xml（spring的配置文件）

<?xml version="1.0" encoding="UTF-8"?>
<beans
    xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:p="http://www.springframework.org/schema/p"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd">
</beans>

参考：Eclipse/MyEclipse上配置Spring环境

创建InjectionDAO接口及其实现类InjectionDAOImpl

InjectionDAO.java

package com.younghare.interfaces;
public interface InjectionDAO {
    public void save(String arg);

}

实现类InjectionDAOImpl .java

package com.younghare.Impl;

import com.younghare.interfaces.InjectionDAO;

public class InjectionDAOImpl implements InjectionDAO {

    @Override
    public void save(String arg) {
        //模拟保存数据到数据库
        System.out.println("模拟保存数据到数据库："+arg);
        
    }
}

创建InjectionService接口及其实现类InjectionServiceImpl

InjectionService.java

package com.younghare.interfaces;

public interface InjectionService {
    public void save(String arg);

}

InjectionServiceImpl.java(实现类)

package com.younghare.Impl;

import com.younghare.interfaces.InjectionDAO;
import com.younghare.interfaces.InjectionService;

public class InjectionServiceImpl implements InjectionService {
    private InjectionDAO injectionDAO; //模拟设值注入时需要为其生成set方法
    //sprint Ioc容器 的设值注入需要这个set方法
    public void setInjectionDAO(InjectionDAO injectionDAO) {
        this.injectionDAO = injectionDAO;
    }


    @Override
    public void save(String arg) {
        //模拟业务操作
        System.out.println("模拟业务操作");
        //对数据进行处理---模拟经过业务逻辑处理
        arg =arg +":"+ this.hashCode();
        //调用DAO把数据保存到数据库
        injectionDAO.save(arg);
        
    }
}

配置applicationContext.xml（对bean进行设置注入配置）

<?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"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd">

    <bean id="injectionService" class ="com.younghare.Impl.InjectionServiceImpl">
    <!--属性name中的injectionDAO对应的是InjectionServiceImpl成员变量的  -->
        <property name="injectionDAO" ref ="injectionDAO"></property>
    </bean>

    <bean id="injectionDAO" class ="com.younghare.Impl.InjectionDAOImpl"></bean>

</beans>
image.png

注意：你也可以在其他文件中进行配置，比如spring-injection.xml，主要是与ClassPathXmlApplicationContext参数对应
ApplicationContext appCtx = new ClassPathXmlApplicationContext("applicationContext.xml");

测试--创建SpringMain.java并实现main方法

测试代码

package com.younghare.main;

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

import com.younghare.Impl.InjectionServiceImpl;
import com.younghare.interfaces.InjectionService;

public class SpringMain {


    public static void main(String[] args) {
        // 测试java bean，配置信息在applicationContext.xml文件中
        ApplicationContext appCtx = new ClassPathXmlApplicationContext("applicationContext.xml");
        
        InjectionService injectionService = (InjectionService) appCtx.getBean("injectionService");
        injectionService.save("这是要保持的数据");

    }

}

运行结果

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现在实现构造器注入

删除xml配置文件中的设值注入的配置，并添加构造器部分的注入

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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:p="http://www.springframework.org/schema/p"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd">
    <!--构造器注入  -->
    <bean id="injectionService" class ="com.younghare.Impl.InjectionServiceImpl">
        <constructor-arg name ="injectionDAO" ref ="injectionDAO"></constructor-arg>
    </bean>

    <bean id="injectionDAO" class ="com.younghare.Impl.InjectionDAOImpl"></bean>

</beans>

InjectionServiceImpl.java中添加InjectionServiceImpl构造器injectionDAO的参数

image.png

再测试运行结果也是

image.png

注意点如果构造器参数的名称定义不同与xml中，则会报错--引用配置错误
如把xml配置中改为injectionDAO3


xml配置引用与构造器参数不一致

单元测试部分

在工程目录中创建测试代码管理目录
myeclipse/new/Source Folder


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创建单元测试类

在工程目录中创建一个test类
myeclipse/new/other

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image.png

SpringTest.java


import static org.junit.Assert.*;

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

import com.younghare.interfaces.InjectionService;

public class SpringTest {
    
    private static ApplicationContext context =null;

    @BeforeClass
    public static void setUpBeforeClass() throws Exception {
        //加载Spring 的配置文件
        context = new ClassPathXmlApplicationContext("applicationContext.xml");
    }

    @Test
    public void test() {
        InjectionService injectionService  =(InjectionService) context.getBean("injectionService");
        injectionService.save("这是要保持的数据");
        
    }

}

运行测试用例

右键/Run as/Junit Test


image.png

单元测试2方法

单元测试基础类UnitTestBase.java

package com.younghare;

import org.junit.After;
import org.junit.Before;
import org.springframework.beans.BeansException;
import org.springframework.context.support.ClassPathXmlApplicationContext;
//import org.springframework.util.StringUtils;
import org.apache.commons.lang.StringUtils;

public class UnitTestBase {
    
    private ClassPathXmlApplicationContext context;
    
    private String springXmlpath;
    
    public UnitTestBase() {}
    
    public UnitTestBase(String springXmlpath) {
        this.springXmlpath = springXmlpath;
    }
    
    @Before
    public void before() {
        if (StringUtils.isEmpty(springXmlpath)) {
//          springXmlpath = "classpath*:spring-*.xml";
            springXmlpath = "classpath*:applicationContext*.xml";
            
        }
        try {
            context = new ClassPathXmlApplicationContext(springXmlpath.split("[,\\s]+"));
            context.start();
        } catch (BeansException e) {
            e.printStackTrace();
        }
    }
    
    @After
    public void after() {
        context.destroy();
    }
    
    @SuppressWarnings("unchecked")
    protected <T extends Object> T getBean(String beanId) {
        try {
            return (T)context.getBean(beanId);
        } catch (BeansException e) {
            e.printStackTrace();
            return null;
        }
    }
    
    protected <T extends Object> T getBean(Class<T> clazz) {
        try {
            return context.getBean(clazz);
        } catch (BeansException e) {
            e.printStackTrace();
            return null;
        }
    }

}

InjectionServiceTest.java (测试测试构造器注入)

package com.younghare;

import static org.junit.Assert.*;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.BlockJUnit4ClassRunner;

import com.younghare.interfaces.InjectionService;

@RunWith(BlockJUnit4ClassRunner.class)
public class InjectionServiceTest extends UnitTestBase {

    public InjectionServiceTest() {
        //super();
        super("classpath:applicationContext.xml");
        
    }
    
    //构造器注入
    @Test
    public void testconstructor() {
        InjectionService service = super.getBean("injectionService");
        service.save("这是要保存的数据");
    }

}
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