spring注解注入

以前在使用spring是通过xml来注入的，每次增加一个service 或 dao都要修改xml 文件，现在也赶时髦用注解来实现。

第一步：在applicationContext.xml进行相应的配置
<?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:jee="http://www.springframework.org/schema/jee" 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/jee http://www.springframework.org/schema/jee/spring-jee-2.5.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd"
    default-lazy-init="true">
    <description>Spring公共配置文件</description>

    <!-- 定义受环境影响易变的变量 -->
    <bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="systemPropertiesModeName" value="SYSTEM_PROPERTIES_MODE_OVERRIDE" />
        <property name="ignoreResourceNotFound" value="true" />
        <property name="locations">
            <list>
                <value>classpath:application.properties</value>
            </list>
        </property>
    </bean>

    <!-- 使用annotation 自动注册bean,并保证@Required,@Autowired的属性被注入 -->
    <context:component-scan base-package="com.jweb" />

    <!-- 数据源配置,在开发测试环境直连数据库 -->
    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="com.mysql.jdbc.Driver" />
        <property name="url" value="jdbc:mysql://localhost:3306/mshop" />
        <property name="username" value="root" />
        <property name="password" value="mysql" />
    </bean>


    <!-- Hibernate配置 -->
    <bean id="sessionFactory" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <property name="namingStrategy">
            <bean class="org.hibernate.cfg.ImprovedNamingStrategy" />
        </property>
        <property name="hibernateProperties">
            <props>
                <prop key="hibernate.dialect">org.hibernate.dialect.MySQLInnoDBDialect</prop>
                <prop key="hibernate.show_sql">${hibernate.show_sql}</prop>
                <prop key="hibernate.hbm2ddl.auto">${hibernate.hbm2ddl.auto}</prop>
            </props>
        </property>
        <property name="packagesToScan" value="com.jweb.entity.*" />
    </bean>

    <!-- 事务管理器配置,单数据源事务 -->
    <bean id="transactionManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
        <property name="sessionFactory" ref="sessionFactory" />
    </bean>
   
    <!-- 使用annotation定义事务 -->
    <tx:annotation-driven transaction-manager="transactionManager" /></beans>

这一步关键是就是红色标识的地方。

第二步：在service及dao上使用注解说明这个组件是service还是dao
package com.jweb.service.user;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import com.jweb.dao.user.UserDao;
import com.jweb.entity.user.User;

@Service
@Transactional
public class UserService {

   @Autowired
    private UserDao mdao;

   
    public UserDao getMdao() {
        return mdao;
    }


    public void setMdao(UserDao mdao) {
        this.mdao = mdao;
    }


    public List<User> findAll(){
        return mdao.findAll();
    }
   
}

package com.jweb.dao.user;

import java.util.List;

import org.hibernate.SessionFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;

import com.jweb.entity.user.User;

@Repository
public class UserDao {
    private SessionFactory sessionFactory;

    public SessionFactory getSessionFactory() {
        return sessionFactory;
    }

    @Autowired
    public void setSessionFactory(SessionFactory sessionFactory) {
        this.sessionFactory = sessionFactory;
    }
   
    @SuppressWarnings("unchecked")
    public List<User> findAll(){
        return sessionFactory.getCurrentSession().createQuery("from User").list();
    }
}

用@service和@Repository只是明确的标识这个是什么类型的类，当然也可以用@Component来标识这个是一个可以注入的组件类。
这样就不在需要在xml文件中配置大量的bean了，是比较方便。

具体的可以参考：

http://www.redsaga.com/spring_ref/2.5/html/beans.html#beans-annotation-config