一、建数据库和表
1.数据库demo1放一张user表
SET FOREIGN_KEY_CHECKS=0;
-- ----------------------------
-- Table structure for user
-- ----------------------------
DROP TABLE IF EXISTS `user`;
CREATE TABLE `user` (
`id` int(11) NOT NULL,
`name` varchar(255) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
-- ----------------------------
-- Records of user
-- ----------------------------
INSERT INTO `user` VALUES ('1', 'aa');
INSERT INTO `user` VALUES ('2', 'bb');2.数据库demo2放一张role表
SET FOREIGN_KEY_CHECKS=0;
-- ----------------------------
-- Table structure for role
-- ----------------------------
DROP TABLE IF EXISTS `role`;
CREATE TABLE `role` (
`id` int(11) NOT NULL,
`name` varchar(255) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
-- ----------------------------
-- Records of role
-- ----------------------------
INSERT INTO `role` VALUES ('1', 'CC');
INSERT INTO `role` VALUES ('2', 'DD');二、pom.xml引入包
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-thymeleaf</artifactId> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <scope>runtime</scope> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-jdbc</artifactId> </dependency> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>2.0.1</version> </dependency> <!-- aop --> <dependency> <groupId>org.aspectj</groupId> <artifactId>aspectjweaver</artifactId> </dependency> <!-- alibaba druid--> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid-spring-boot-starter</artifactId> <version>1.1.10</version> </dependency> <!-- dynamic--> <dependency> <groupId>com.typesafe.dynamicdatasource</groupId> <artifactId>dynamic-data-source_2.11</artifactId> </dependency>
三、用generator插件生成user、role两张表的实体类、mapper.java、mapper.xml
User.java Role.java UserMapper.java RoleMapper.java UserMapper.xml RoleMapper.xml
四、配置application.yml
server: port: 8088 mybatis: mapper-locations: classpath:mapper/*.xml spring: datasource: db1: url: jdbc:mysql://localhost:3306/demo1?useUnicode=true&characterEncoding=utf8&serverTimezone=GMT username: root password: root type: com.alibaba.druid.pool.DruidDataSource #驱动包 driver-class-name: com.mysql.cj.jdbc.Driver #初始连接数 initial-size: 5 #最小空闲数 min-idle: 5 #最大活动数 max-active: 20 #等待超时时间 max-wait: 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 time-between-eviction-runs-millis: 60000 # 配置一个连接在池中最小生存的时间，单位是毫秒 min-evictable-idle-time-millis: 300000 #验证数据库连接的查询语句,MYSQL是select 1 validation-query: SELECT 1 FROM DUAL #空闲时测试，testOnBorrow和testOnReturn在生产环境一般是不开启的，主要是性能考虑。失效连接主要通过testWhileIdle保证 test-while-idle: true test-on-borrow: false test-on-return: false #打开PSCache，并指定每个链接上的PSCache大小 pool-prepared-statements: true max-pool-prepared-statement-per-connection-size: 20 #配置监控统计拦截的filters,去掉后监控界面sql无法统计，‘wall'用于防火墙，此处是filter修改的地方 filters: stat,wall #通过connectproperties属性来打开mergesql功能：慢sql记录 connection-properties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000 #合并多个DruidDataSource useGlobalDataSourceStat: true db2: url: jdbc:mysql://localhost:3306/demo2?useUnicode=true&characterEncoding=utf8&serverTimezone=GMT username: root password: root type: com.alibaba.druid.pool.DruidDataSource #驱动包 driver-class-name: com.mysql.cj.jdbc.Driver #初始连接数 initial-size: 5 #最小空闲数 min-idle: 5 #最大活动数 max-active: 20 #等待超时时间 max-wait: 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 time-between-eviction-runs-millis: 60000 # 配置一个连接在池中最小生存的时间，单位是毫秒 min-evictable-idle-time-millis: 300000 #验证数据库连接的查询语句,MYSQL是select 1 validation-query: SELECT 1 FROM DUAL #空闲时测试，testOnBorrow和testOnReturn在生产环境一般是不开启的，主要是性能考虑。失效连接主要通过testWhileIdle保证 test-while-idle: true test-on-borrow: false test-on-return: false #打开PSCache，并指定每个链接上的PSCache大小 pool-prepared-statements: true max-pool-prepared-statement-per-connection-size: 20 #配置监控统计拦截的filters,去掉后监控界面sql无法统计，‘wall'用于防火墙，此处是filter修改的地方 filters: stat,wall #通过connectproperties属性来打开mergesql功能：慢sql记录 connection-properties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000 #合并多个DruidDataSource useGlobalDataSourceStat: true
五、启动类扫描mapper.java文件
@SpringBootApplication
@MapperScan("com.example.demo.dao")
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
}六、定义DataSourceConfig， 将application.yml中的配置导入DataSource中，并注入到bean
@Configuration
public class DataSourceConfig {
//从配置文件配置数据源
@Primary
@Bean(name="datasource1")
@ConfigurationProperties("spring.datasource.db1")
public DataSource dataSource1(){
return new DruidDataSource();
}
//从配置文件配置数据源
@Bean(name="datasource2")
@ConfigurationProperties("spring.datasource.db2")
public DataSource dataSource2(){
return new DruidDataSource();
}
//动态数据源 进行数据源切换
@Bean(name="dynamicDataSource")
public DataSource dynamicDataSource(){
DynamicDataSource dynamicDatasource=new DynamicDataSource();
//设置默认数据源
dynamicDatasource.setDefaultTargetDataSource(dataSource1());
//配置多数据源
Map<Object,Object> dsMap=new HashMap<>();
dsMap.put("datasource1",dataSource1());
dsMap.put("datasource2",dataSource2());
//将多数据源放到数据源池中
dynamicDatasource.setTargetDataSources(dsMap);
return dynamicDatasource;
}
}七、定义动态数据源切换类DynamicDataSourceContextHolder
public class DynamicDataSourceContextHolder {
private static final ThreadLocal<String> contextHolder=new ThreadLocal<>();
//设置数据源名称
public static void setDB(String dbType){
contextHolder.set(dbType);
}
//获取数据源名称
public static String getDB(){
return contextHolder.get();
}
//清除数据源名
public static void clearDB(){
contextHolder.remove();
}
}八、定义获取动态数据源类DynamicDataSource
public class DynamicDataSource extends AbstractRoutingDataSource {
@Override
protected Object determineCurrentLookupKey() {
return DynamicDataSourceContextHolder.getDB();
}
}九、定义mybatis配置类，将DynamicDataSource放入SqlSessionFactoryBean中
@EnableTransactionManagement
@Configuration
public class MyBatisConfig {
@Resource(name = "dynamicDataSource")
private DataSource dynamicDataSource;
@Bean
public SqlSessionFactory sqlSessionFactory() throws Exception {
SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
sqlSessionFactoryBean.setDataSource(dynamicDataSource);//将动态数据源bean配置到sqlsessionfactory
sqlSessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mapper/*.xml"));
return sqlSessionFactoryBean.getObject();
}
@Bean
public PlatformTransactionManager platformTransactionManager() {
return new DataSourceTransactionManager(dynamicDataSource);
}
}十、定义用于切换数据源的注解TargetDataSource
@Target({ElementType.METHOD,ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface TargetDataSource {
String value() default "datasource1";
}十一、定义切面DynamicDataSourceAspect，用于拦截注解，并执行数据源切换功能
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@Aspect
@Component
public class DynamicDataSourceAspect {
@Before("@annotation(targetDataSource)")
public void beforeSwitchDS(JoinPoint point,TargetDataSource targetDataSource){
DynamicDataSourceContextHolder.setDB(targetDataSource.value());
}
@After("@annotation(targetDataSource)")
public void afterSwitchDS(JoinPoint point,TargetDataSource targetDataSource){
DynamicDataSourceContextHolder.clearDB();
}
}十二、测试类Test
@RestController
public class Test {
@Autowired
private RoleMapper roleMapper;
@Autowired
private UserMapper userMapper;
//未使用TargetDataSource注解，则使用默认数据源，即datasource1
@RequestMapping("/ds1")
public String selectDataSource1(){
return userMapper.selectByPrimaryKey(1).toString();
}
//使用了注解，则数据源为注解中指定的datasource2
@RequestMapping("/ds2")
@TargetDataSource("datasource2")
public String selectDataSource2(){
return roleMapper.selectByPrimaryKey(1).toString();
}
}测试
1.输入
http://localhost:8088/ds1
返回
↓
2.输入
http://localhost:8088/ds2
返回
↓
