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);
}
}