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。