Spring注入

Spring注入

Spring注入是指在启动Spring容器加载bean配置的时候，完成对变量的赋值行为。

常用的两种注入方式：

• setter注入
• 构造注入

<?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" >
     <!-- setter注入 -->
	<bean id="setterService" class="com.injavawetrust.ioc.injection.service.SetterServiceImpl">
		<property name="setterDao" ref="setterDao"></property>
	</bean>
	<!-- 构造注入 -->
	<bean id="constructorService" class="com.injavawetrust.ioc.injection.service.ConstructorServiceImpl">
		<constructor-arg name="constructorDao" ref="constructorDao"></constructor-arg>
	</bean>

	<bean id="setterDao" class="com.injavawetrust.ioc.injection.dao.SetterDaoImpl"></bean>
	<bean id="constructorDao" class="com.injavawetrust.ioc.injection.dao.ConstructorDaoImpl"></bean>

</beans>

import junit.framework.TestCase;

import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.BlockJUnit4ClassRunner;
import org.springframework.beans.BeansException;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.injavawetrust.ioc.injection.service.ConstructorService;
import com.injavawetrust.ioc.injection.service.SetterService;
/**
 * @author InJavaWeTrust
 */
@RunWith(BlockJUnit4ClassRunner.class)
public class TestInjection extends TestCase {

	private ClassPathXmlApplicationContext context;
	@Before
	public void before() {
		try {
			context = new ClassPathXmlApplicationContext("classpath:spring-injavawetrust.xml");
			context.start();
		} catch (BeansException e) {
			e.printStackTrace();
		}
	}

	@After
	public void after() {
		context.destroy();
	}

	@Test
	public void tesSetter() {
		SetterService service = (SetterService) context.getBean("setterService");
		service.say("setter-injavawetrust");
	}

	@Test
	public void testConstructor() {
		ConstructorService service = (ConstructorService) context.getBean("constructorService");
		service.say("constructor-injavawetrust");
	}

}

/**
 * @author InJavaWeTrust
 */
public interface SetterService {
	public void say(String str);
}

import com.injavawetrust.ioc.injection.dao.SetterDao;
/**
 * @author InJavaWeTrust
 */
public class SetterServiceImpl implements SetterService {

	private SetterDao setterDao;

	public void setSetterDao(SetterDao setterDao) {
		this.setterDao = setterDao;
	}

	@Override
	public void say(String str) {
		System.out.println("接受参数：" + str);
		str = "hello " + str;
		setterDao.say(str);
	}
}

/**
 * @author InJavaWeTrust
 */
public interface SetterDao {
	public void say(String str);
}

/**
 * @author InJavaWeTrust
 */
public class SetterDaoImpl implements SetterDao {

	@Override
	public void say(String str) {
		System.out.println("say: " + str);
	}
}

/**
 * @author InJavaWeTrust
 */
public interface ConstructorService {
	public void say(String str);
}

import com.injavawetrust.ioc.injection.dao.ConstructorDao;
/**
 * @author InJavaWeTrust
 */
public class ConstructorServiceImpl implements ConstructorService {

	private ConstructorDao constructorDao;

	public ConstructorServiceImpl(ConstructorDao constructorDao) {
		this.constructorDao = constructorDao;
	}

	@Override
	public void say(String str) {
		System.out.println("接受参数：" + str);
		str = "hello " + str;
		constructorDao.say(str);
	}
}

/**
 * @author InJavaWeTrust
 */
public interface ConstructorDao {
	public void say(String str);
}

/**
 * @author InJavaWeTrust
 */
public class ConstructorDaoImpl implements ConstructorDao {

	@Override
	public void say(String str) {
		System.out.println(str);
	}
}