一个项目中怎么划分数据库,可以通过具体业务需求。

项目中数据源怎么如何划分,通过注解的方式@Datasource(ref="") 在方法上指定,会连接指定的数据源,这种方式比较繁琐。如果有1000个方法,就得写1000个这种注解。所以一般通过分包名的方式。

通过分包名来划分数据源:

SpringBoot 集成多数据源-LMLPHP

1,mysql 里面有两个库,testdb,testdb2,里面各有一张user表,数据结构是一样的

2,建立实体类:user

@Data //相当于@Setter @Getter
public class User {
private int id;
private String username;
private String sex;
private Date birthday;
private String address;
}

2,datasource 包下有DataSource1Config,DataSource2Config,如下:

package com.baiyue.datasource;

import javax.sql.DataSource;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager; // DataSource01
@Configuration // 注册到springboot容器中
@MapperScan(basePackages = "com.baiyue.db1", sqlSessionFactoryRef = "db1SqlSessionFactory")
public class DataSource1Config {
@Bean(name = "db1DataSource") //@Bean是注入到Spring 容器中
@ConfigurationProperties(prefix = "spring.datasource.db1")//读取配置文件中以spring.datasource.db1 开头的
public DataSource testDataSource() {
return DataSourceBuilder.create().build();
}
@Primary
@Bean(name = "db1SqlSessionFactory")
public SqlSessionFactory testSqlSessionFactory(@Qualifier("db1DataSource") DataSource dataSource) throws Exception {
SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
bean.setDataSource(dataSource);
bean.setMapperLocations(
new PathMatchingResourcePatternResolver().getResources("classpath:com/baiyue/db1/mapping/*Mapper.xml"));
return bean.getObject();
} /**
* 事务
*/
@Bean(name = "db1TransactionManager")
public DataSourceTransactionManager testTransactionManager(@Qualifier("db1DataSource") DataSource dataSource) {
return new DataSourceTransactionManager(dataSource);
} @Bean(name = "db1SqlSessionTemplate")
public SqlSessionTemplate testSqlSessionTemplate(
@Qualifier("db1SqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
return new SqlSessionTemplate(sqlSessionFactory);
} }

DataSource2:

package com.baiyue.datasource;

import javax.sql.DataSource;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager; // DataSource01
@Configuration // 注册到springboot容器中
@MapperScan(basePackages = "com.baiyue.db2", sqlSessionFactoryRef = "db2SqlSessionFactory")
public class DataSource2Config { @Bean(name = "db2DataSource") //@Bean是注入到Spring 容器中
@ConfigurationProperties(prefix = "spring.datasource.db2")//读取配置文件中以spring.datasource.db2 开头的
public DataSource testDataSource() {
return DataSourceBuilder.create().build();
} @Bean(name = "db2SqlSessionFactory")
public SqlSessionFactory testSqlSessionFactory(@Qualifier("db2DataSource") DataSource dataSource) throws Exception {
SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
bean.setDataSource(dataSource);
bean.setMapperLocations(
new PathMatchingResourcePatternResolver().getResources("classpath:com/baiyue/db2/mapping/*Mapper.xml"));
return bean.getObject();
} /**
* 事务
*/
@Bean(name = "db2TransactionManager")
public DataSourceTransactionManager testTransactionManager(@Qualifier("db2DataSource") DataSource dataSource) {
return new DataSourceTransactionManager(dataSource);
} @Bean(name = "db2SqlSessionTemplate")
public SqlSessionTemplate testSqlSessionTemplate(
@Qualifier("db2SqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
return new SqlSessionTemplate(sqlSessionFactory);
} }

通过 @Configuration // 注册到springboot容器中,在启动类中会去读取所有的Bean,通过两个类以及配置文件,能够获取到不同包下的业务层对应不同的数据源..

#多数据源
spring:
datasource:
db1:
driver-class-name: com.mysql.jdbc.Driver
jdbcUrl: jdbc:mysql://localhost:3306/testdb?useUnicode=true&characterEncoding=utf-8
username: root
password: 123456 db2:
driver-class-name: com.mysql.jdbc.Driver
jdbcUrl: jdbc:mysql://localhost:3306/testdb2?useUnicode=true&characterEncoding=utf-8
username: root
password: 123456

3,db1 下的mapper,xml,service,sevice层需要指定业务相应的事务管理,否则会报有两个事务管理的错

package com.baiyue.db1.mapper;

import com.baiyue.entity.User;

public interface UserMapperdb1 {

    void insertUser(User user);

    User selectUserById(int id);

}
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.baiyue.db1.mapper.UserMapperdb1"> <!-- 根据 id 查询 user 表中的数据 id:唯一标识符,此文件中的id值不能重复 resultType:返回值类型,一条数据库记录也就对应实体类的一个对象
parameterType:参数类型,也就是查询条件的类型 -->
<select id="selectUserById" resultType="com.baiyue.entity.User" parameterType="int">
<!-- 这里和普通的sql 查询语句差不多,对于只有一个参数,后面的 #{id}表示占位符,里面不一定要写id,写啥都可以,但是不要空着,如果有多个参数则必须写pojo类里面的属性 -->
select * from user where id = #{id}
</select> <insert id="insertUser" parameterType="com.baiyue.entity.User">
insert into
user(id,username,sex,birthday,address)
value(#{id},#{username},#{sex},#{birthday},#{address})
</insert> </mapper>
package com.baiyue.db1.service;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional; import com.baiyue.db1.mapper.UserMapperdb1;
import com.baiyue.entity.User; import lombok.extern.slf4j.Slf4j; @Service
@Slf4j
public class UserServicedb1 { @Override
public String toString() {
// TODO Auto-generated method stub
return super.toString();
} @Autowired
private UserMapperdb1 userMapper; @Transactional("db1TransactionManager")//指定事务管理
public void insertUser(User user) {
userMapper.insertUser(user);
}; public User selectUserById(int id) {
User user = userMapper.selectUserById(id);
return user;
}; }

4,同理,db2 的mapper,xml,service

package com.baiyue.db2.mapper;

import com.baiyue.entity.User;

public interface UserMapperdb2 {

    void insertUser(User user);

    User selectUserById(int id);
}
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.baiyue.db2.mapper.UserMapperdb2"> <!-- 根据 id 查询 user 表中的数据 id:唯一标识符,此文件中的id值不能重复 resultType:返回值类型,一条数据库记录也就对应实体类的一个对象
parameterType:参数类型,也就是查询条件的类型 -->
<select id="selectUserById" resultType="com.baiyue.entity.User" parameterType="int">
<!-- 这里和普通的sql 查询语句差不多,对于只有一个参数,后面的 #{id}表示占位符,里面不一定要写id,写啥都可以,但是不要空着,如果有多个参数则必须写pojo类里面的属性 -->
select * from user where id = #{id}
</select> <insert id="insertUser" parameterType="com.baiyue.entity.User">
insert into
user(id,username,sex,birthday,address)
value(#{id},#{username},#{sex},#{birthday},#{address})
</insert>
</mapper>
package com.baiyue.db2.service;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional; import com.baiyue.db2.mapper.UserMapperdb2;
import com.baiyue.entity.User;
import lombok.extern.slf4j.Slf4j; @Service
@Slf4j
public class UserServicedb2 { @Autowired
private UserMapperdb2 userMapper; @Transactional("db2TransactionManager")//指定事务管理
public void insertUser(User user) {
log.info("正在添加");
userMapper.insertUser(user);
}; public User selectUserById(int id) {
User user = userMapper.selectUserById(id);
return user;
}; }

5,controller 层:

package com.baiyue.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController; import com.baiyue.db1.service.UserServicedb1;
import com.baiyue.db2.service.UserServicedb2;
import com.baiyue.entity.User; @RestController
public class Mybatis { @Autowired
private UserServicedb1 userService1; @Autowired
private UserServicedb2 userService2; @RequestMapping("/insertUserdb1")
public String insertUserdb1(){
User user = new User();
user.setUsername("chris");
user.setSex("male");
userService1.insertUser(user);
return "db1success";
} @RequestMapping("/insertUserdb2")
public String insertUserdb2() {
User user = new User();
user.setUsername("chris");
user.setSex("male");
userService2.insertUser(user);
return "db2success";
} }

6,启动类

@MapperScan({"com.baiyue.db1.mapper","com.baiyue.db2.mapper"})
@ComponentScan(basePackages = "com.baiyue") //因为有一些bean 不在当前包或者子包下面,所以@SpringBootApplication 会有些bean 扫不到
@SpringBootApplication
public class App {
public static void main(String[] args) {
SpringApplication.run(App.class, args);
}
}

这样,能够多数据源操作了。。。

05-21 20:35
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