以下记录了一个小小的Spring3的annotation的应用笔记。
文件列表：
UserService-interface
UserDao-interface
UserServiceImpl-UserService接口的实现
UserDaoImpl-UserDao接口的实现
User-实体类
package com.niewj.model;
public class User {
private String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
package com.niewj.service;
import javax.annotation.Resource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Service;
import com.niewj.dao.LogDao;
import com.niewj.dao.UserDao;
import com.niewj.model.User;
@Service("userServiceImplementation")
// @Component/@Repository/@Controller/@Service
@Scope("singleton")
// @Scope("prototype")
public class UserServiceImpl implements UserService {
// 也可以此处声明，也可以在setter处声明。
/* @Autowired
@Qualifier("userDaoImplementation")*/
//@Resource(name="userDaoImplementation")// 不指定的话,他会找setter方法，最后可以会退到，找byType匹配。
private UserDao uuuserDao;
private LogDao logDao;
public UserDao getUuuserDao() {
return uuuserDao;
}
/*
@Autowired// (required=false)
@Qualifier("userDaoImplementation")// id/name
*/
@Resource(name="userDaoImplementation")
public void setUuuserDao(UserDao uuuserDao) {
this.uuuserDao = uuuserDao;
}
public LogDao getLogDao() {
return logDao;
}
@Autowired
public void setLogDao(LogDao logDao) {
this.logDao = logDao;
}
@Override
public boolean regist(User user) {
logDao.log();
return uuuserDao.save(user);
}
}
package com.niewj.dao;
import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import org.springframework.stereotype.Repository;
import com.niewj.model.User;
/* @Repository/@Controller/@Service都属于@Component,只是为了更明显的标注业务层、控制层、还是Dao层 */
@Repository("userDaoImplementation")
public class UserDaoImpl implements UserDao {
@PostConstruct// 相当于<bean init-method="init">
public void init(){
System.err.println("实例化DAO后，会马上调用此方法。");
}
@PreDestroy//相当于<bean destroy-method="destroy">
public void destroy(){
System.err.println("销毁DAO之前，会执行此方法。");
}
@Override
public boolean save(User user) {
System.err.println("新增用户：" +user.getName());
return true;
}
}
package com.niewj.dao;
import org.springframework.stereotype.Repository;
@Repository("logDao")
public class LogDaoImpl implements LogDao {
@Override
public void log() {
System.out.println("Logging......记录在日志............OK");
}
}
package com.niewj;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.niewj.model.User;
import com.niewj.service.UserService;
import com.niewj.service.UserServiceImpl;
public class AnnotationTest {
@Test
public void testIocAnnotation() {
ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
UserService loginService = ac.getBean("userServiceImplementation", UserServiceImpl.class);
User user = new User();
user.setName("dotjar");
loginService.regist(user);
}
}
<?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:tx="http://www.springframework.org/schema/tx" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd"> <import resource="beans.xml" /> </beans>
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:p="http://www.springframework.org/schema/p" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd"> <!-- 开启Annotation支持 如果有context:component-scan可以省去此处声明--> <!-- <context:annotation-config /> --> <context:component-scan base-package="com.niewj"> </context:component-scan> </beans>
1.UserServiceImpl中的@Service中的字串应该和getBean中的一致；
2.UserDaoImpl中的@Repository中参数应该和UserServiceImpl中Setter方法处的@Autowired@Qualifier("dao参数")一致
3.配置文件中开启注解支持：
*1.配置文件中开启context命名空间支持：<beans>标记中加入：
<1>加入【xmlns】：【xmlns:context="http://www.springframework.org/schema/context"】
<2>加入【xsi:schemaLocation】：
【http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.2.xsd】
*2.配置文件中开启注解支持：
<context:annotation-config />
*3.因为有<context:component-scan>所以， <context:annotation-config />可以省去。
小结：
1.
@Repository/@Controller/@Service都属于@Component,只是为了更明显的标注业务层、控制层、还是Dao层
2.
@Resource(name="userDaoImplementation")// 不指定name的话,他会找setter方法，按照byName找不到，最后可以byType匹配。
3.
@Autowired // byType自动装配
@Qualifier("userDaoImplementation") //byName，必须有@Autowired同时出现。