Spring_新注解

Spring_新注解

使用Spring原始注解还不能全部代替xml配置文件，还需要使用注解替代的配置如下

1. 非自定义的Bena的配置
2. 加载properties文件的配置
3. 组件扫描配置
4. 引入其他文件
   新注解

@Configuration	用于指定当前类是Spring配置类，当创建容器时会从该类上加载注解
@ComponentScan	用于指定Spring在初始化容器时要扫描的包
@Bean	使用在方法上，标注将该方法的返回值存储到Spring容器中
@PropertySource	用于加载properties文件中的配置
@import	用于导入其他配置类

核心配置类（SpringConfiguation.class）

示例
DataSourceConfiguration.class

package com.lzy.config;

import com.mchange.v2.c3p0.ComboPooledDataSource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.PropertySource;

import javax.sql.DataSource;

//加载配置源文件
// <context:property-placeholder location="classpath:jdbc.properties"></context:property-placeholder>
@PropertySource("classpath:jdbc.properties")

public class DataSourceConfiguration {
    @Value("${jdbc.driver}")
    private String driver;
    @Value("${jdbc.url}")
    private String url;
    @Value("${jdbc.username}")
    private String username;
    @Value("${jdbc.password}")
    private String password;
//        取代的xml配置
//    <bean id="" class="com.mchange.v2.c3p0.ComboPooledDataSource">
//        <property name="driverClass" value="${jdbc.driver}"></property>
//        <property name="jdbcUrl" value="${jdbc.url}"></property>
//        <property name="user" value="${jdbc.username}"></property>
//        <property name="password" value="${jdbc.password}"></property>
//    </bean>

    //Spring 会将当前方法的返回值以指定名称存储到Spring容器中
    @Bean("dataSource")
    public DataSource getDataSource() throws Exception {
        ComboPooledDataSource dataSource = new ComboPooledDataSource();
        dataSource.setDriverClass(driver);
        dataSource.setJdbcUrl(url);
        dataSource.setUser(username);
        dataSource.setPassword(password);
        return dataSource;
    }
}

SpringConfiguration.class

package com.lzy.config;
import org.springframework.context.annotation.*;
//Spring 核心配置类
@Configuration

//<context:component-scan base-package="com.lzy"></context:component-scan>
@ComponentScan("com.lzy")

//  <import resource="">
@Import(DataSourceConfiguration.class)
public class SpringConfiguration {
}

main

package com.lzy.web;

import com.lzy.config.SpringConfiguration;
import com.lzy.service.UserService;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class UserController {
    public static void main(String[] args){
        //ClassPathXmlApplicationContext app = new ClassPathXmlApplicationContext("applicationContext.xml");

        ApplicationContext app = new AnnotationConfigApplicationContext(SpringConfiguration.class);
        UserService userService = (UserService)app.getBean("userService");
        userService.save();

    }
}