spring进阶教程(一):减少spring的XML

前言

作为一个java程序猿，相信大家都都用过spring，大家应该注意到了，spring的配置基本都是用xml实现，其实这样很难查错切难以理解，下面告诉大家如何减少spirng的XML配置，实现xml中的bean转到java文件。

参考项目：https://github.com/bigbeef/cppba-web
开源地址：https://github.com/bigbeef
个人博客：http://blog.cppba.com

1.看看我们传统的xml配置文件

这个是我们使用druid配置dataSource的xml代码：

<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource" init-method="init" destroy-method="close">
        <!-- 基本属性 url、user、password -->
        <property name="url" value="${jdbc.url}" />
        <property name="username" value="${jdbc.user}" />
        <property name="password" value="${jdbc.password}" />

        <!-- 配置初始化大小、最小、最大 -->
        <property name="initialSize" value="1" />
        <property name="minIdle" value="1" />
        <property name="maxActive" value="20" />

        <!-- 配置获取连接等待超时的时间 -->
        <property name="maxWait" value="60000" />

        <!-- 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒 -->
        <property name="timeBetweenEvictionRunsMillis" value="60000" />

        <!-- 配置一个连接在池中最小生存的时间，单位是毫秒 -->
        <property name="minEvictableIdleTimeMillis" value="300000" />

        <property name="validationQuery" value="SELECT 'x'" />
        <property name="testWhileIdle" value="true" />
        <property name="testOnBorrow" value="false" />
        <property name="testOnReturn" value="false" />

        <!-- 打开PSCache，并且指定每个连接上PSCache的大小 -->
        <property name="poolPreparedStatements" value="true" />
        <property name="maxPoolPreparedStatementPerConnectionSize" value="20" />

        <!-- 配置监控统计拦截的filters，去掉后监控界面sql无法统计 -->
        <property name="filters" value="stat" />
    </bean>

2.新建一个Configuration.java

下面是我自己开源项目cppba-web中hibernate.java的配置信息：

package com.cppba.config.hibernate;

import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.orm.hibernate4.HibernateTransactionManager;
import org.springframework.orm.hibernate4.LocalSessionFactoryBean;
import org.springframework.transaction.annotation.EnableTransactionManagement;

import javax.sql.DataSource;
import java.sql.SQLException;
import java.util.Properties;

import static com.cppba.config.ApplicationInitializer.propertySourcesPropertyResolver;

@Configuration
@EnableTransactionManagement
public class HibernateConfiguration {
    //datasource
    @Bean(initMethod = "init", destroyMethod = "close")
    public DataSource dataSource() throws SQLException {
        DruidDataSource druidDataSource = new DruidDataSource();
        //正式环境（修改jdbc.properties中jdbc.environment.real属性）
        if(propertySourcesPropertyResolver.getProperty("jdbc.environment.real").equals("true")){
            druidDataSource.setUrl(propertySourcesPropertyResolver.getProperty("jdbc.real.url"));
            druidDataSource.setUsername(propertySourcesPropertyResolver
                    .getProperty("jdbc.real.user"));
            druidDataSource.setPassword(propertySourcesPropertyResolver
                    .getProperty("jdbc.real.password"));
        }else{
            //测试环境
            druidDataSource.setUrl(propertySourcesPropertyResolver.getProperty("jdbc.test.url"));
            druidDataSource.setUsername(propertySourcesPropertyResolver
                    .getProperty("jdbc.test.user"));
            druidDataSource.setPassword(propertySourcesPropertyResolver
                    .getProperty("jdbc.test.password"));
        }
        druidDataSource.setInitialSize(1);
        druidDataSource.setMinIdle(1);
        druidDataSource.setMaxActive(20);
        druidDataSource.setMaxWait(60000);
        druidDataSource.setTimeBetweenEvictionRunsMillis(60000);
        druidDataSource.setMinEvictableIdleTimeMillis(300000);
        druidDataSource.setValidationQuery("SELECT　'x'");
        druidDataSource.setTestWhileIdle(true);
        druidDataSource.setTestOnBorrow(false);
        druidDataSource.setTestOnReturn(false);
        return druidDataSource;
    }

    //sessionFactory
    @Bean
    public LocalSessionFactoryBean sessionFactory() throws SQLException {
        LocalSessionFactoryBean localSessionFactoryBean = new LocalSessionFactoryBean();
        localSessionFactoryBean.setDataSource(this.dataSource());
        Properties properties1 = new Properties();
        properties1.setProperty("hibernate.dialect", "org.hibernate.dialect.MySQL5Dialect");
        properties1.setProperty("hibernate.show_sql", "false");
        localSessionFactoryBean.setHibernateProperties(properties1);
        localSessionFactoryBean.setPackagesToScan("*");
        return localSessionFactoryBean;
    }

    //txManager事务开启
    @Bean
    public HibernateTransactionManager txManager() throws SQLException {
        HibernateTransactionManager hibernateTransactionManager = new HibernateTransactionManager();
        hibernateTransactionManager.setSessionFactory(sessionFactory().getObject());
        return hibernateTransactionManager;
    }
}

3.重点提示

xml中bean转成java代码的重点在于：
1.配置类上加上@Configuration
2.bean方法上面加上@Bean