Spring 02 Spring注解开发

 

                                    

dao层

public interface UserDao {
    void insertUser();
}

实现类
/*@Component(value = "userDao") 配置到实例里去 或者直接用下面的Repository*/
@Repository("userDao")
public class UserDaoImpl implements UserDao {
    @Override
    public void insertUser() {
        System.out.println("持久层 添加用户");
    }
}

service层

public interface UserService {
    void insertUser();
}

实现类
@Component("userService") /*或 @Service("userService")*/
public class UserServiceImpl implements UserService {

    @Autowired /*按照类型自动注入*/
    @Qualifier("userDao")/*按照名称自动注入 不能单独使用，必须与@Autowired一起使用*/
  //  @Resource(name = "userDao")/*java的注解，用于代替@Autowired和 @Qualifier  相当于上面两个一起*/
    private UserDao userDao;

    public UserDao getUserDao() {
        return userDao;
    }

    public void setUserDao(UserDao userDao) {
        this.userDao = userDao;
    }

    @Override
    public void insertUser() {
        System.out.println("业务层 添加用户");
        userDao.insertUser();
    }
}

applicationContext.xml   注：这里不用，加上只是起一个对比作用，注解开发用注解代替这个配置文件

<?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
            ">

    <!-- 有多个时 location="classpath:jdbc.properties,jdbc2.properties"-->
    <context:property-placeholder location="classpath:jdbc.properties" system-properties-mode="NEVER"/>
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="driverClassName" value="${jdbc.driver}"/>
        <property name="url" value="${jdbc.url}"/>
        <property name="username" value="${jdbc.username}"/>
        <property name="password" value="${jdbc.password}"/>
    </bean>
    <bean id="userDao" class="com.dao.impl.UserDaoImpl"/>

    <!--注解扫描-->
    <context:component-scan base-package="com"/><!--扫描所有包，或者用逗号隔开com.dao.iml,com.service.iml-->

</beans>

test

    @Test
    public void testUserServiseAnno(){
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        UserService userService = context.getBean("userService", UserService.class);
        userService.insertUser();
    }

 

数据池加载的几种方法：

 导入第三方bean

方法一：

SpringConfih.java

@Configuration//表示该类是Spring配置类，用于代替ApplicationContext.xml
@ComponentScan(value = {"com.dao.impl","com.service.impl"})
@Import(value = {DataSourseConfig.class})/*导入第三方bean*/
public class SpringConfig {
}

DataSourseConfig.java

import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;

import javax.sql.DataSource;
 public class DataSourseConfig {

    @Bean
    public DataSource dataSource(){
        DruidDataSource dataSource= new DruidDataSource();
        dataSource.setDriverClassName("com.mysql.jdbc.Driver");
        dataSource.setUrl("jdbc:mysql://localhost:3307/myb?useSSL=false&useUnicode=true&characterEncoding=UTF-8");
        dataSource.setUsername("root");
        dataSource.setPassword("123");
        return  dataSource;
    }

}

test

   @Test
    public void testConfiguration(){
        ApplicationContext context = new AnnotationConfigApplicationContext(SpringConfig.class);
        UserService userService = context.getBean("userService", UserService.class);
        userService.insertUser();
    }

方法二：使用jdbc.properties

SpringConfih.java

@Configuration//表示该类是Spring配置类，用于代替ApplicationContext.xml
@ComponentScan(value = {"com.dao.impl","com.service.impl"})
@Import(value = {DataSourseConfig.class})/*导入第三方bean*/
@PropertySource(value = "classpath:jdbc.properties")
public class SpringConfig {
}

jdbc.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3307/myb?useSSL=false&useUnicode=true&characterEncoding=UTF-8
jdbc.username=root
jdbc.password=123

DataSourseConfig.java

 public class DataSourseConfig {

    @Value("${jdbc.driver}")
    private String driverClassName;
    @Value("${jdbc.url}")
    private String url;
    @Value("${jdbc.username}")
    private String username;
    @Value("${jdbc.password}")
    private String password;
    @Bean
    public DataSource dataSource(){
        DruidDataSource dataSource= new DruidDataSource();
        dataSource.setDriverClassName(driverClassName);
        dataSource.setUrl(url);
        dataSource.setUsername(username);
        dataSource.setPassword(password);
        return dataSource;
    }
}

 

test

@Test
public void testDataSource() throws SQLException {
    ApplicationContext context = new AnnotationConfigApplicationContext(SpringConfig.class);
    DataSource dataSource = context.getBean("dataSource",DataSource.class);
    System.out.println(dataSource.getConnection());
}