学习 Spring (二) Spring 注入

Spring入门篇 学习笔记

常用的两种注入方式

1. 设值注入
2. 构造注入

示例准备工作

添加 InjectionDAO：

public interface InjectionDAO {

	void save(String arg);

}

添加 InjectionDAOImpl：

public class InjectionDAOImpl implements InjectionDAO {

	public void save(String arg) {
		System.out.println("保存数据：" + arg);
	}

}

添加 InjectionService：

public interface InjectionService {

	void save(String arg);

}

设值注入

添加 InjectionServicePropertyImpl：

public class InjectionServicePropertyImpl implements InjectionService {

	private InjectionDAO injectionDAO;

	public void setInjectionDAO(InjectionDAO injectionDAO) {
		this.injectionDAO = injectionDAO;
	}

	public void save(String arg) {
		System.out.println("Service(Property)接收参数：" + arg);
		arg = arg + ":" + this.hashCode();
		injectionDAO.save(arg);
	}

}

添加配置文件 classpath:spring-injection-property.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="injectionService" class="com.karonda.ioc.injection.service.InjectionServicePropertyImpl">
        <property name="injectionDAO" ref="injectionDAO"></property>
     </bean>

    <bean id="injectionDAO" class="com.karonda.ioc.injection.dao.InjectionDAOImpl"></bean>
 </beans>

添加测试 TestInjectionProperty：

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

	public TestInjectionProperty() {
		super("classpath:spring-injection-property.xml");
	}

	@Test
	public void testSetter() {
		InjectionService service = super.getBean("injectionService");
		service.save("这是要保存的数据");
	}

}

构造注入

添加 InjectionServiceConstructorImpl：

public class InjectionServiceConstructorImpl implements InjectionService {

	private InjectionDAO injectionDAO;

	//构造器注入
	public InjectionServiceConstructorImpl(InjectionDAO injectionDAO) {
		this.injectionDAO = injectionDAO;
	}

	public void save(String arg) {
		//模拟业务操作
		System.out.println("Service(Constructor)接收参数：" + arg);
		arg = arg + ":" + this.hashCode();
		injectionDAO.save(arg);
	}

}

添加配置文件 spring-injection-constructor.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="injectionService" class="com.karonda.ioc.injection.service.InjectionServiceConstructorImpl">
        	<constructor-arg name="injectionDAO" ref="injectionDAO"></constructor-arg>
        </bean>

        <bean id="injectionDAO" class="com.karonda.ioc.injection.dao.InjectionDAOImpl"></bean>

 </beans>

添加测试 TestInjectionConstructor

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

	public TestInjectionConstructor() {
		super("classpath:spring-injection-constructor.xml");
	}

	@Test
	public void testCons() {
		InjectionService service = super.getBean("injectionService");
		service.save("这是要保存的数据");
	}

}

源码：learning-spring