spring——依赖注入DI(spring-test方式)

spring——依赖注入DI(spring-test方式)

本文主要介绍如何实现spring 的依赖注入，并且浅显的讲述一下注入需要注意的事项。
1、创建一个maven项目
mvn archetype:generate -DarchetypeCatalog=internal

2、修改pom.xml，引入需要的依赖，首先spring-context，还是spring-test，最后还有junit。

<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<springframework.version>4.3.7.RELEASE</springframework.version>
</properties>

<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
<!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>${springframework.version}</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.springframework/spring-test -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>${springframework.version}</version>
</dependency>

</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>1.8</source>
<target>1.8</target>
<encoding>utf-8</encoding>
</configuration>
</plugin>
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<version>3.0.0</version>
<configuration>
<archive>
<manifest>
<mainClass>com.xueyoucto.xueyou.App</mainClass>
</manifest>
</archive>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
<executions>
<execution>
<id>make-assembly</id> <!-- this is used for inheritance merges -->
<phase>package</phase> <!-- bind to the packaging phase -->
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>

3、添加类Person和Body

package com.xueyou.demo;

import org.springframework.stereotype.Component;

@Component
public class Person {
public String getName() {
return name;
}

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

private String name;

}

package org.xueyou.demo;

import org.springframework.stereotype.Component;

@Component
public class Body {
public int getId() {
return id;
}

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

private int id;

}

3、在配置类App中，添加ComponentScan。需要注意的是，这里需要指定扫描的包

package com.xueyou.demo;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

/**
* Hello world!
*/
@Configuration
@ComponentScan(basePackages = {"org.xueyou.demo","com.xueyou.demo"})
public class App {
public static void main(String[] args) {
System.out.println("Hello World!");
}
}

4、新建一个测试类

package com.xueyou.demo;

import org.junit.Assert;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.xueyou.demo.Body;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = App.class)
public class Springtest {

@Autowired
private Body body;

@Autowired
private Person person;

@Test
public void testBodyIsNull(){
Assert.assertNotNull(body);
}

@Test
public void testPersonIsNull(){
Assert.assertNotNull(person);
}

}

5、运行测试类，结果如下：



6、从运行结果中我们能看到，Person类和Student类已经被依赖注入到spring中，spring能够使用这两个类了。