（四）SpringBoot2.0基础篇- 多数据源，JdbcTemplate和JpaRepository

在日常开发中，经常会遇到多个数据源的问题，而SpringBoot也有相关API:Configure Two DataSources:https://docs.spring.io/spring-boot/docs/1.5.4.RELEASE/reference/htmlsingle/#howto-two-datasources

本文SpringBoot版本为2.0（由于2.0之前的版本和之后的版本配置会有些许不同，2.0之前的版本推荐一位大牛的博文：http://blog.didispace.com/springbootmultidatasource/）下面会介绍这两种多数据源的配置方法，希望大家多多指教！

　　1、添加applicaton.properties数据库连接信息，有两个数据源，一个为主，一个为从：

app.datasource.foo.url=jdbc:mysql://192.168.1.121:3306/test
app.datasource.foo.username=root
app.datasource.foo.password=admincss
app.datasource.foo.driver-class-name=com.mysql.jdbc.Driver

app.datasource.bar.url=jdbc:mysql://192.168.1.121:3306/test2
app.datasource.bar.username=root
app.datasource.bar.password=admincss
app.datasource.bar.driver-class-name=com.mysql.jdbc.Driver

　　2、创建数据源类：

package com.cn.datasource;

import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.jdbc.DataSourceProperties;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.jdbc.core.JdbcTemplate;

import javax.sql.DataSource;

/**
 * @program: spring-boot-example
 * @description: 数据源配置类
 * @author:
 * @create: 2018-05-03 14:35
 **/

@Configuration
public class JdbcDataSourceConfig {

    @Primary
    @Bean(name = "dataSourcePropertiesFoo")
    @Qualifier("dataSourcePropertiesFoo")
    @ConfigurationProperties(prefix="app.datasource.foo")
    public DataSourceProperties dataSourcePropertiesFoo() {
        return new DataSourceProperties();
    }

    @Primary
    @Bean(name = "fooDataSource")
    @Qualifier("fooDataSource")
    @ConfigurationProperties(prefix="app.datasource.foo")
    public DataSource fooDataSource(@Qualifier("dataSourcePropertiesFoo") DataSourceProperties dataSourceProperties) {
        return dataSourceProperties.initializeDataSourceBuilder().build();
    }

    @Bean(name = "dataSourcePropertiesBar")
    @Qualifier("dataSourcePropertiesBar")
    @ConfigurationProperties(prefix="app.datasource.bar")
    public DataSourceProperties dataSourcePropertiesBar() {
        return new DataSourceProperties();
    }

    @Bean(name = "barDataSource")
    @Qualifier("barDataSource")
    @ConfigurationProperties(prefix="app.datasource.bar")
    public DataSource barDataSource(@Qualifier("dataSourcePropertiesBar") DataSourceProperties dataSourceProperties) {
        return dataSourceProperties.initializeDataSourceBuilder().build();
    }

    @Bean(name = "fooJdbcTemplate")
    @Qualifier("fooJdbcTemplate")
    public JdbcTemplate fooJdbcTemplate(@Qualifier("fooDataSource") DataSource dataSource) {
        return new JdbcTemplate(dataSource);
    }

    @Bean(name = "barJdbcTemplate")
    @Qualifier("barJdbcTemplate")
    public JdbcTemplate barJdbcTemplate(@Qualifier("barDataSource") DataSource dataSource) {
        return new JdbcTemplate(dataSource);
    }
}

　　3、创建简单的测试bean、controller、service、entityRowMapper：

package com.cn.entity.u;

import java.io.Serializable;

/**
 * @program: spring-boot-example
 * @description: 用户类
 * @author:
 * @create: 2018-05-02 09:59
 **/
public class User implements Serializable{

    private int id;
    private String name;
    private int age;
    private String address;

    @Override
    public String toString() {
        return "User{" +
            "id=" + id +
            ", name='" + name + '\'' +
            ", age=" + age +
            ", address='" + address + '\'' +
            '}';
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }
}

User.java