<parent>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-parentartifactId>
<version>2.2.1.RELEASEversion>
parent>
<dependencies>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-webartifactId>
dependency>
<dependency>
<groupId>org.mybatis.spring.bootgroupId>
<artifactId>mybatis-spring-boot-starterartifactId>
<version>1.3.2version>
dependency>
<dependency>
<groupId>mysqlgroupId>
<artifactId>mysql-connector-javaartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-aopartifactId>
dependency>
<dependency>
<groupId>com.alibabagroupId>
<artifactId>druid-spring-boot-starterartifactId>
<version>1.1.9version>
dependency>
<dependency>
<groupId>org.projectlombokgroupId>
<artifactId>lombokartifactId>
<version>1.18.20version>
<scope>providedscope>
dependency>
dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-maven-pluginartifactId>
plugin>
plugins>
build>
2、编写启动类
@ServletComponentScan
@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class})
public class DynamicDataSourceDemoApplication {
public static void main(String[] args) {
SpringApplication.run(DynamicDataSourceDemoApplication.class, args);
}
}
3、编写配置文件
server:
port: 8888
spring:
application:
name: dynamic-data-source-mybatis-demo
datasource:
# 主数据源
master:
driverClassName: com.mysql.jdbc.Driver
jdbcUrl: jdbc:mysql://127.0.0.1:3306/test_master?useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=convertToNull&allowMultiQueries=true&serverTimezone=GMT
username: root
password: root
# 从数据源
slave:
enabled: true # 从数据源开关/默认关闭
driverClassName: com.mysql.jdbc.Driver
jdbcUrl: jdbc:mysql://127.0.0.1:3306/test_slave?useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=convertToNull&allowMultiQueries=true&serverTimezone=GMT
username: root
password: root
initialSize: 5
minIdle: 5
maxActive: 20
maxWait: 60000
timeBetweenEvictionRunsMillis: 60000
minEvictableIdleTimeMillis: 300000
validationQuery: select count(*) from dual
testWhileIdle: true
testOnBorrow: true
testOnReturn: false
poolPreparedStatements: true
maxPoolPreparedStatementPerConnectionSize: 20
filters: stat
connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000
timeBetweenLogStatsMillis: 0
mybatis:
mapper-locations: classpath:/mapper/*
configuration:
mapUnderscoreToCamelCase: true
log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
4、编写数据源枚举类
public enum DataSourceType {
MASTER,
SLAVE,
}
5、编写自定义注解
@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface DataSource {
/**
* 切换数据源名称
*/
DataSourceType value() default DataSourceType.MASTER;
}
6、编写相关配置类
DynamicDataSource
public class DynamicDataSource extends AbstractRoutingDataSource {
public DynamicDataSource(DataSource defaultTargetDataSource, Map<Object, Object> targetDataSources) {
super.setDefaultTargetDataSource(defaultTargetDataSource);
super.setTargetDataSources(targetDataSources);
// afterPropertiesSet()方法调用时用来将targetDataSources的属性写入resolvedDataSources中的
super.afterPropertiesSet();
}
/**
* 根据Key获取数据源的信息
*
* @return
*/
@Override
protected Object determineCurrentLookupKey() {
return DynamicDataSourceContextHolder.getDataSourceType();
}
}
DynamicDataSourceContextHolder
public class DynamicDataSourceContextHolder {
public static final Logger log = LoggerFactory.getLogger(DynamicDataSourceContextHolder.class);
/**
* 使用ThreadLocal维护变量,ThreadLocal为每个使用该变量的线程提供独立的变量副本,
* 所以每一个线程都可以独立地改变自己的副本,而不会影响其它线程所对应的副本。
*/
private static final ThreadLocal<String> CONTEXT_HOLDER = new ThreadLocal<>();
/**
* 设置数据源变量
* @param dataSourceType
*/
public static void setDataSourceType(String dataSourceType){
log.info("切换到{}数据源", dataSourceType);
CONTEXT_HOLDER.set(dataSourceType);
}
/**
* 获取数据源变量
* @return
*/
public static String getDataSourceType(){
return CONTEXT_HOLDER.get();
}
/**
* 清空数据源变量
*/
public static void clearDataSourceType(){
CONTEXT_HOLDER.remove();
}
}
DataSourceConfig
@Configuration
public class DataSourceConfig {
private static final Logger log = LoggerFactory.getLogger("DataSourceConfig");
//主数据源
@Value("${spring.datasource.master.jdbcUrl}")
private String masterJdbcUrl;
@Value("${spring.datasource.master.username}")
private String masterUsername;
@Value("${spring.datasource.master.password}")
private String masterPassword;
@Value("${spring.datasource.master.driverClassName}")
private String masterDriverClassName;
//从数据源
@Value("${spring.datasource.slave.jdbcUrl}")
private String slaveJdbcUrl;
@Value("${spring.datasource.slave.username}")
private String slaveUsername;
@Value("${spring.datasource.slave.password}")
private String slavePassword;
@Value("${spring.datasource.slave.driverClassName}")
private String slaveDriverClassName;
//其他相关配置
@Value("${spring.datasource.initialSize}")
private int initialSize;
@Value("${spring.datasource.minIdle}")
private int minIdle;
@Value("${spring.datasource.maxActive}")
private int maxActive;
@Value("${spring.datasource.maxWait}")
private int maxWait;
@Value("${spring.datasource.timeBetweenEvictionRunsMillis}")
private int timeBetweenEvictionRunsMillis;
@Value("${spring.datasource.minEvictableIdleTimeMillis}")
private int minEvictableIdleTimeMillis;
@Value("${spring.datasource.validationQuery}")
private String validationQuery;
@Value("${spring.datasource.testWhileIdle}")
private boolean testWhileIdle;
@Value("${spring.datasource.testOnBorrow}")
private boolean testOnBorrow;
@Value("${spring.datasource.testOnReturn}")
private boolean testOnReturn;
@Value("${spring.datasource.poolPreparedStatements}")
private boolean poolPreparedStatements;
@Value("${spring.datasource.maxPoolPreparedStatementPerConnectionSize}")
private int maxPoolPreparedStatementPerConnectionSize;
@Value("${spring.datasource.filters}")
private String filters;
@Value("${spring.datasource.connectionProperties}")
private String connectionProperties;
@Value("${spring.datasource.timeBetweenLogStatsMillis}")
private int timeBetweenLogStatsMillis;
@Bean
public DataSource masterDataSource() {
return generateDataSource(masterJdbcUrl,masterUsername,masterPassword,masterDriverClassName);
}
@Bean
@ConditionalOnProperty(prefix = "spring.datasource.slave", name = "enabled", havingValue = "true")
public DataSource slaveDataSource() {
return generateDataSource(slaveJdbcUrl, slaveUsername, slavePassword, slaveDriverClassName);
}
private DruidDataSource generateDataSource(String url, String username, String password, String driverClassName){
DruidDataSource datasource = new DruidDataSource();
datasource.setUrl(url);
datasource.setUsername(username);
datasource.setPassword(password);
datasource.setDriverClassName(driverClassName);
//configuration
datasource.setInitialSize(initialSize);
datasource.setMinIdle(minIdle);
datasource.setMaxActive(maxActive);
datasource.setMaxWait(maxWait);
datasource.setTimeBetweenEvictionRunsMillis(timeBetweenEvictionRunsMillis);
datasource.setMinEvictableIdleTimeMillis(minEvictableIdleTimeMillis);
datasource.setValidationQuery(validationQuery);
datasource.setTestWhileIdle(testWhileIdle);
datasource.setTestOnBorrow(testOnBorrow);
datasource.setTestOnReturn(testOnReturn);
datasource.setPoolPreparedStatements(poolPreparedStatements);
datasource.setMaxPoolPreparedStatementPerConnectionSize(maxPoolPreparedStatementPerConnectionSize);
try {
datasource.setFilters(filters);
} catch (SQLException e) {
System.err.println("druid configuration initialization filter: " + e);
}
datasource.setConnectionProperties(connectionProperties);
datasource.setTimeBetweenLogStatsMillis(timeBetweenLogStatsMillis);
return datasource;
}
@Bean(name = "dynamicDataSource")
@Primary
public DynamicDataSource dataSource(DataSource masterDataSource, DataSource slaveDataSource) {
Map<Object, Object> targetDataSources = new HashMap<>();
targetDataSources.put(DataSourceType.MASTER.name(), masterDataSource);
targetDataSources.put(DataSourceType.SLAVE.name(), slaveDataSource);
return new DynamicDataSource(masterDataSource, targetDataSources);
}
@Bean(name = "sqlSessionFactory")
public SqlSessionFactory sqlSessionFactory(@Qualifier("dynamicDataSource") DataSource dataSource)
throws Exception {
final SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();
sessionFactory.setDataSource(dataSource);
sessionFactory.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath*:/mapper/**/?*Mapper.xml"));
sessionFactory.setConfiguration(globalMyBatisConfig());
return sessionFactory.getObject();
}
@Bean
@ConfigurationProperties(prefix = "mybatis.configuration")
public org.apache.ibatis.session.Configuration globalMyBatisConfig() {
return new org.apache.ibatis.session.Configuration();
}
/**
* 配置事务管理器
*/
@Bean
public DataSourceTransactionManager transactionManager(@Qualifier("dynamicDataSource") DataSource dataSource) {
return new DataSourceTransactionManager(dataSource);
}
}
DataSourceAspect
@Aspect
@Order(1)
@Component
public class DataSourceAspect {
//@within在类上设置
//@annotation在方法上进行设置
@Pointcut("execution(public * com.qzh.*.dao..*.*(..))")
public void pointcut() {}
@Before("pointcut()")
public void doBefore(JoinPoint joinPoint)
{
Method method = ((MethodSignature)joinPoint.getSignature()).getMethod();
DataSource dataSource = method.getAnnotation(DataSource.class);//获取方法上的注解
if(dataSource == null){
Class<?> clazz= joinPoint.getTarget().getClass().getInterfaces()[0];
dataSource =clazz.getAnnotation(DataSource.class);//获取类上面的注解
if(dataSource == null) {
return;
}
}
if (dataSource != null) {
DynamicDataSourceContextHolder.setDataSourceType(dataSource.value().name());
}
}
@After("pointcut()")
public void after(JoinPoint point) {
//清理掉当前设置的数据源,让默认的数据源不受影响
DynamicDataSourceContextHolder.clearDataSourceType();
}
}
7、实体类
@Data
@ToString
public class User {
private String name;
private Integer age;
public User(){}
}
8、编写Dao层
接口
//没有DataSource注解,则默认在主数据源中进行sql *** 作
@Repository
@Mapper
public interface UserMapper {
int insert(User user);
@Select("SELECT * FROM user")
List<User> selectList();
}
@Repository
@Mapper
//从数据源中进行sql *** 作
@DataSource(DataSourceType.SLAVE)
public interface SlaveUserMapper {
int insert(User user);
@Select("SELECT * FROM user")
List<User> selectList();
}
xml文件
-
SlaveUserMapper.xml
DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="com.qzh.dynamicDataSourceDemo.dao.SlaveUserMapper"> <insert id="insert" useGeneratedKeys="true" keyColumn="id" keyProperty="id" parameterType="com.qzh.dynamicDataSourceDemo.entity.User"> INSERT INTO `user` (`name`,age) VALUES (#{name},#{age}) insert> mapper>
-
UserMapper.xml
DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="com.qzh.dynamicDataSourceDemo.dao.UserMapper"> <insert id="insert" useGeneratedKeys="true" keyColumn="id" keyProperty="id" parameterType="com.qzh.dynamicDataSourceDemo.entity.User"> INSERT INTO `user` (`name`,age) VALUES (#{name},#{age}) insert> mapper>
public interface UserService {
String addUser();
String getUserFromMaster();
String getUserFromSlave();
}
实现类
@Service
public class UserServiceImpl implements UserService {
@Autowired
private UserMapper masterUserMapper;
@Autowired
private SlaveUserMapper slaveUserMapper;
@Override
public String addUser() {
User master = new User();
master.setName("test_master");
master.setAge(10);
masterUserMapper.insert(master);
User slave = new User();
slave.setName("test_slave");
slave.setAge(100);
slaveUserMapper.insert(slave);
return "success";
}
@Override
public String getUserFromMaster() {
return masterUserMapper.selectList().toString();
}
@Override
public String getUserFromSlave() {
return slaveUserMapper.selectList().toString();
}
}
10、编写controller层
@RestController
@RequestMapping("/test")
public class TestController {
@Autowired
private UserService userService;
@PostMapping("/testAddUser")
public String testAddUser() {
return userService.addUser();
}
@GetMapping("/testGetUserFromMaster")
public String testGetUserFromMaster() {
return userService.getUserFromMaster();
}
@GetMapping("/testGetUserFromSlave")
public String testGetUserFromSlave() {
return userService.getUserFromSlave();
}
}
启动服务,调用接口测试即可。
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