开发环境：
jdk：JDK1.8+
gradle：Gradle4.6+
Spring：2.1.3.RELEASE+
当数据库数据达到一定数量的时候，数据库的响应将会有所缓慢，一般都会采取一些措施。例如，读写分离、分表分库、主从服务、缓存技术等等。这里采用的是多库多表。
test库中user_info表：
test2库中user_info表：
#####导入依赖
// https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-web
compile group: 'org.springframework.boot', name: 'spring-boot-starter-web', version: '2.1.3.RELEASE'
// https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-jdbc
compile group: 'org.springframework.boot', name: 'spring-boot-starter-jdbc', version: '2.1.3.RELEASE'
// https://mvnrepository.com/artifact/org.projectlombok/lombok
compileOnly group: 'org.projectlombok', name: 'lombok', version: '1.18.6'
// https://mvnrepository.com/artifact/mysql/mysql-connector-java
compile group: 'mysql', name: 'mysql-connector-java', version: '8.0.15'
//mybatis插件
compile group: 'org.mybatis.generator', name: 'mybatis-generator-core', version: '1.3.5'
compile group: 'tk.mybatis', name: 'mapper', version: '4.0.2'
// https://mvnrepository.com/artifact/org.mybatis.spring.boot/mybatis-spring-boot-starter
compile group: 'org.mybatis.spring.boot', name: 'mybatis-spring-boot-starter', version: '2.0.0'
HikariCP在spring-boot-starter-jdbc中已经被引入（Spring默认数据源）
#####项目结构
#####配置文件配置（application.yaml）默认数据源信息
spring:
datasource:
url: jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=CONVERT_TO_NULL&serverTimezone=Asia/Shanghai&allowMultiQueries=true
username: root
password: admin
sql-script-encoding: UTF-8
#####读取配置信息DataSourceConfig.java，创建默认的数据源
package utry.hikaricp.config;
import com.zaxxer.hikari.HikariDataSource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import utry.hikaricp.DataSourceProvider;
import utry.hikaricp.info.DataSourceInfo;
import utry.hikaricp.source.MyHikariDataSource;
/**
* @author szs
* @date 2019/3/14 14:22
*/
@Configuration
@EnableTransactionManagement
public class DataSourceConfig {
@Value("${spring.datasource.url}")
private String url;
@Value("${spring.datasource.username}")
private String userName;
@Value("${spring.datasource.password}")
private String password;
@Bean
@ConditionalOnMissingBean(MyHikariDataSource.class)
public MyHikariDataSource dataSource() {
DataSourceInfo info = new DataSourceInfo();
info.setUrl(url);
info.setUsername(userName);
info.setPassword(password);
HikariDataSource dataSource = DataSourceProvider.create(info);
MyHikariDataSource hikariCPDataSource = new MyHikariDataSource();
hikariCPDataSource.updateDataSourceMap("1", dataSource);
return hikariCPDataSource;
}
}
#####通过DataSourceProvider创建HikariDataSource
package utry.hikaricp;
import com.zaxxer.hikari.HikariConfig;
import com.zaxxer.hikari.HikariDataSource;
import utry.hikaricp.info.DataSourceInfo;
/**
* @author szs
* @date 2019/3/14 15:07
*/
public class DataSourceProvider {
public static HikariDataSource create(DataSourceInfo sourceInfo) {
HikariConfig hikariConfig = new HikariConfig();
hikariConfig.setUsername(sourceInfo.getUsername());
hikariConfig.setPassword(sourceInfo.getPassword());
hikariConfig.setJdbcUrl(sourceInfo.getUrl());
hikariConfig.setDriverClassName("com.mysql.jdbc.Driver");
return new HikariDataSource(hikariConfig);
}
}
#####最核心的数据源的类MyHikariDataSource.java
package utry.hikaricp.source;
import com.zaxxer.hikari.HikariDataSource;
import org.springframework.jdbc.datasource.AbstractDataSource;
import javax.sql.DataSource;
import java.io.Closeable;
import java.io.IOException;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.Map;
/**
* @author szs
* @date 2019/3/14 14:30
*/
public class MyHikariDataSource extends AbstractDataSource {
private static Map<String, HikariDataSource> dataSourceMap = new HashMap<>(1);
@Override
public Connection getConnection() throws SQLException {
return dataSourceMap.get("1").getConnection();
}
@Override
public Connection getConnection(String username, String password) throws SQLException {
return dataSourceMap.get("1").getConnection(username, password);
}
private void destroy(){
DataSource dataSource = dataSourceMap.get("1");
Closeable closeable = (Closeable) dataSource;
if (closeable != null) {
try {
closeable.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
public void updateDataSourceMap(String key, HikariDataSource value) {
destroy();
dataSourceMap.put(key, value);
}
}
只要将上面这个类中的DataSourceMap集合中的HikariDataSource修改就能实现数据源的切换了，调用updateDataSourceMap()方法修改即可（修改之前，先关闭之前的数据源，这里写死的map中key=1，读者可以实现动态设置）
#####实体类UserInfo.java
package utry.hikaricp.model;
public class UserInfo {
private Integer id;
private String remarks;
public UserInfo() {
}
public UserInfo(Integer id, String remarks) {
this.id = id;
this.remarks = remarks;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getRemarks() {
return remarks;
}
public void setRemarks(String remarks) {
this.remarks = remarks;
}
}
######HikariCpController.java两个接口：
- 更新数据源
- 查询用户信息
package utry.hikaricp.controller;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import utry.hikaricp.factory.HikariCPDataSourceFactory;
import utry.hikaricp.mapper.UserInfoMapper;
import utry.hikaricp.model.UserInfo;
/**
* @author szs
* @date 2019/3/18 11:50
*/
@RestController
public class HikariCpController {
@Autowired
private UserInfoMapper mapper;
@Autowired
private HikariCPDataSourceFactory factory;
@RequestMapping("update")
public void info(String username, String password, String url) {
factory.reload(username, password, url);
}
@RequestMapping("get")
public UserInfo get() {
try {
UserInfo userInfo = mapper.selectByPrimaryKey(1);
return userInfo;
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
}
#####启动项目
- 调用get接口，返回的数据是test库中的
- 调用update请求更新数据源
调用成功之后，可以看到，之前的数据源已经被shutdown，初始化了一个新的数据源
- 再次调用get请求，可以看到获取的test2数据库中的数据
