Spring 常用注入注解（annotation）和其对应xml标签

使用注解需要修改bean.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"
  xmlns:context="http://www.springframework.org/schema/context"
  xsi:schemaLocation="http://www.springframework.org/schema/beans
      http://www.springframework.org/schema/beans/spring-beans.xsd
      http://www.springframework.org/schema/context
      http://www.springframework.org/schema/context/spring-context.xsd">

  <context:annotation-config/>

  <bean class="example.SimpleMovieCatalog">
      <qualifier value="main"/>
      <!-- inject any dependencies required by this bean -->
  </bean>

  <bean class="example.SimpleMovieCatalog">
      <qualifier value="action"/>
      <!-- inject any dependencies required by this bean -->
  </bean>

  <bean id="movieRecommender" class="example.MovieRecommender"/>

</beans>

黄色部分内容会使spring加载​​AutowiredAnnotationBeanPostProcessor等可以识别注解的bean。​​

​@AutoWire​，自动注入，一般放在属性的set方法上，会为该属性自动注入。默认的注入是使用byType，就是根据xml中bean的类型去匹配。

可以和​@Qualifier匹配使用。​

注解实现方式：

package com.bjsxt.service;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.beans.factory.annotation.Qualifier;

import com.bjsxt.dao.UserDAO;

import com.bjsxt.model.User;

public class UserService {

    private UserDAO userDAO; 

    public void init() {

        System.out.println("init");

    }

    public void add(User user) {

        userDAO.save(user);

    }

    public UserDAO getUserDAO() {

        return userDAO;

    }

    ​@Autowired​

    public void setUserDAO(@​Qualifier​("u") UserDAO userDAO) {//​Qualifier：根据qualifier标签去查找，也可以根据name或者id去查找匹配的bean​

        this.userDAO = userDAO;

    }

    public void destroy() {

        System.out.println("destroy");

    }

}

对应的xml实现方式：

<?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-2.5.xsd"​​             >

  <bean name="userDAO" class="com.bjsxt.dao.impl.UserDAOImpl">       <property name="daoId" value="1"></property>      </bean>        <bean name="userDAO2" class="com.bjsxt.dao.impl.UserDAOImpl">          <property name="daoId" value="2"></property>      </bean>         <bean id="userService" class="com.bjsxt.service.UserService" ​scope="prototype​" ​autowire="byType​"><!-- 也可以设在beans标签上，好像是default-autowire ​scope="prototype"​表示每次都创建一个新的实例对应的有singleton--只有一个实例 -->     </bean>   

</beans>

​@Resource​

​此标签也用于注入属性。相对来说用的比较多。​

该标签需要导入J2EE的JAR包：common-annotations.jar

javax.annotation.Resource，默认byName，如果找不到对应name会去找对应type

    ​@Resource​

    public void setUserDAO（UserDAO userDAO) { 

        this.userDAO = userDAO;

    }

​@Resource（name=”uuu”) //可以byName​

​以上两种注解虽然可以在代码中设置注入，但是还要求在xml文件中配置bean。​

​Component可以省去。​

5.10.3 Using filters to customize scanning

By default, classes annotated with ​​@Component​​​, ​​@Repository​​​, ​​@Service​​​, ​​@Controller​​​, or a custom annotation that itself is annotated with ​​@Component​​ are the only detected candidate components. However, you can modify and extend this behavior simply by applying custom filters. Add them as ​include-filter​ or ​exclude-filter​ sub-elements of the​​component-scan​​​ element. Each filter element requires the ​​type​​​ and ​​expression​​ attributes. The following table describes the filtering options.

<?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:context="​​​​http://www.springframework.org/schema/context"​​​​

       xsi:schemaLocation="​​​​http://www.springframework.org/schema/beans​​​​

​​

           ​​

           ​​

           ​​

    <context:annotation-config />

    <context:​component-scan​ base-package​="com.bjsxt​"/>

</beans>

​scan：扫描。表示扫描某个包和其自包，将能作为组件（添加了@Component）的内容解析出来。​

package com.bjsxt.dao.impl;

import org.springframework.stereotype.Component;

import com.bjsxt.dao.UserDAO;

import com.bjsxt.model.User;

​@Component("u")​ //这样写表示这个类是一个组件，在另外一个类看来它就是一个资源。不指定它的key默认会是userDAOImpl（即类名首字母改成小写）

public class UserDAOImpl implements UserDAO {

    public void save(User user) {

        //Hibernate

        //JDBC

        //XML

        //NetWork

        System.out.println("user saved!");

    }

}

package com.bjsxt.service;

import javax.annotation.Resource;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.beans.factory.annotation.Qualifier;

import org.springframework.stereotype.Component;

import com.bjsxt.dao.UserDAO;

import com.bjsxt.model.User;

​@Component("userService")​

public class UserService {

    private UserDAO userDAO; 

    public void init() {

        System.out.println("init");

    }

    public void add(User user) {

        userDAO.save(user);

    }

    public UserDAO getUserDAO() {

        return userDAO;

    }

    @Resource(name="u")

    public void setUserDAO( UserDAO userDAO) {

        this.userDAO = userDAO;

    }

    public void destroy() {

        System.out.println("destroy");

    }

}

​额外的一些内容：​

<bean id="userService" class="com.bjsxt.service.UserService" ​init-method="init" destroy-method="destroy" scope="prototype​">

​scope对应的注解是@Scope（“”）​

​init-method对应的注解是@PostConstruct，表示构造完成之后再执行它注解的方法。​

​destroy-method对应的注解是@PreDestroy，容器销毁之前。​