Java零基础尝试mybatis-plus读写分离 - Powered by Discuz! Archiver

tsx81428 发表于 2023-10-16 23:10:37

零基础尝试mybatis-plus读写分离

看了好几篇博友写的文章，关于spring-boot整合mybatis-plus实现读写分离，不过都是缺这少那的，跑不起来，所以自己实操了一次，做个记录
实现方式为使用Aop切面
1、增加数据库枚举类
/**
* 数据库类型
*/
public enum DBTypeEnum {
/**
* 主节点
*/
MASTER,
/**
* 从
*/
SLAVE
}2、配置数据源
/**
* 多数据源配置
*/
@AutoConfigureBefore(DruidDataSourceAutoConfigure.class)
@Configuration
@ConfigurationProperties(prefix = "spring.datasource.druid")
@Data
public class DataSourceConfig {

private int initialSize;
private int maxActive;
private int minIdle;
private long maxWait;
private long minEvictableIdleTimeMillis;
private long timeBetweenEvictionRunsMillis;
private boolean testWhileIdle;

/**
* 配置主数据源
*
* @return 数据源
*/
@Bean(name = "masterDataSource")
@ConfigurationProperties(prefix = "spring.datasource.druid.master" )
public DataSource masterDataSource() {
   DruidDataSource druidDataSource = new DruidDataSource();
   parseDruidConfig(druidDataSource);
   return druidDataSource;
}

/**
* 配置从数据源
*
* @return 数据源
*/
@Bean(name = "slaveDataSource")
@ConfigurationProperties(prefix = "spring.datasource.druid.slave")
public DataSource slaveDataSource() {
   DruidDataSource druidDataSource = new DruidDataSource();
   parseDruidConfig(druidDataSource);
   return druidDataSource;
}

private void parseDruidConfig(DruidDataSource dataSource) {
   dataSource.setInitialSize(initialSize);
   dataSource.setMaxActive(maxActive);
   dataSource.setMinIdle(minIdle);
   dataSource.setMaxWait(maxWait);
   dataSource.setMinEvictableIdleTimeMillis(minEvictableIdleTimeMillis);
   dataSource.setTimeBetweenEvictionRunsMillis(timeBetweenEvictionRunsMillis);
   dataSource.setTestWhileIdle(testWhileIdle);
}

/**
* 配置路由数据源
*
* @param masterDataSource 主节点
* @param slaveDataSource 从节点
* @return 数据源
*/
@Bean(name = "myRoutingDataSource")
@DependsOn({"masterDataSource", "slaveDataSource"})
@Primary
public DataSource myRoutingDataSource(@Qualifier("masterDataSource") DataSource masterDataSource,
                                       @Qualifier("slaveDataSource") DataSource slaveDataSource) {
   Map<Object, Object> targetDataSources = new HashMap<>(3);
   targetDataSources.put(DBTypeEnum.MASTER, masterDataSource);
   targetDataSources.put(DBTypeEnum.SLAVE, slaveDataSource);
   MyRoutingDataSource myRoutingDataSource = new MyRoutingDataSource();
   //设置默认数据源
   myRoutingDataSource.setDefaultTargetDataSource(masterDataSource);
   myRoutingDataSource.setTargetDataSources(targetDataSources);
   return myRoutingDataSource;
}
}3、线程轮循切换主从数据库(多主多从的情况下适用)
/**
* 通过ThreadLocal将数据源设置到每个线程上下文中
*/
public class DataSourceContextHolder {
private static final ThreadLocal<DBTypeEnum> CONTEXT_HOLDER = new ThreadLocal<>();

private static final AtomicInteger COUNTER = new AtomicInteger(-1);

public static void set(DBTypeEnum dbType) {
   CONTEXT_HOLDER.set(dbType);
}

public static DBTypeEnum get() {
   return CONTEXT_HOLDER.get();
}

public static void clear(){
   CONTEXT_HOLDER.remove();
}

public static void master() {
   set(DBTypeEnum.MASTER);
   System.out.println("切换到master");
}

public static void slave() {
   //轮询
   int index = COUNTER.getAndIncrement() % 2;
   if (COUNTER.get() > 9999) {
         COUNTER.set(-1);
   }
//    if (index == 0) {
//          set(DBTypeEnum.SLAVE1);
//          System.out.println("切换到slave1");
//    } else {
//          set(DBTypeEnum.SLAVE2);
//          System.out.println("切换到slave2");
//    }
   set(DBTypeEnum.SLAVE);
   System.out.println("切换到slave2");
}
}4、声明路由数据源key(多主多从的情况下适用)
/**
* 声明路由数据源key
*/
public class MyRoutingDataSource extends AbstractRoutingDataSource {
@Nullable
@Override
protected Object determineCurrentLookupKey() {
   return DataSourceContextHolder.get();
}
}5、强制使用主/从数据库注解
/**
* 强制使用主数据库注解
*/
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD})
public @interface DataSourceMaster {
}/**
* 强制使用从数据库注解
*/
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD})
public @interface DataSourceSlave {
}6、切面类(从库注解会报错，不知道什么原因)
/**
* 使用aop实现数据源切换
*/
@Aspect
@Component
public class DataSourceAop {

// /**
// * 需要读的方法,切面
// */
// @Pointcut("!@annotation(com.readWriteSeparation.annotation.DataSourceSlave)" +
//          "|| execution(* com.readWriteSeparation.service..*.select*(..)) " +
//          "|| execution(* com.readWriteSeparation.service..*.get*(..))" +
//          "|| execution(* com.readWriteSeparation.service..*.query*(..))" +
//          "|| execution(* com.readWriteSeparation.service..*.find*(..)))")
// public void readPointcut() { }

/**
* 需要读的方法,切面
*/
@Pointcut("execution(* com.readWriteSeparation.service..*.select*(..)) " +
         "|| execution(* com.readWriteSeparation.service..*.get*(..))" +
         "|| execution(* com.readWriteSeparation.service..*.query*(..))" +
         "|| execution(* com.readWriteSeparation.service..*.find*(..)))")
public void readPointcut() { }

/**
* 写切面
*/
@Pointcut("@annotation(com.readWriteSeparation.annotation.DataSourceMaster) " +
         "|| execution(* com.readWriteSeparation.service..*.insert*(..))" +
         "|| execution(* com.readWriteSeparation.service..*.save*(..))" +
         "|| execution(* com.readWriteSeparation.service..*.add*(..))" +
         "|| execution(* com.readWriteSeparation.service..*.update*(..))" +
         "|| execution(* com.readWriteSeparation.service..*.edit*(..))" +
         "|| execution(* com.readWriteSeparation.service..*.delete*(..))" +
         "|| execution(* com.readWriteSeparation.service..*.remove*(..))")
public void writePointcut() { }

@Before("readPointcut()")
public void read() {
   DataSourceContextHolder.slave();
}

@Before("writePointcut()")
public void write() {
   DataSourceContextHolder.master();
}

@After("readPointcut()")
public void readAfter() {
   DataSourceContextHolder.clear();
}

@After("writePointcut()")
public void writeAfter() {
   DataSourceContextHolder.clear();
}
}7、.yml文件配置
spring:
datasource:
druid:
   master:
   username: root
   password: 12345678
   url: jdbc:mysql://192.168.10.15/zeroStart?characterEncoding=UTF-8&useSSL=true&requireSSL=false&zeroDateTimeBehavior=convertToNull&useSSL=false&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=Asia/Shanghai&allowMultiQueries=true
   driver-class-name: com.mysql.cj.jdbc.Driver
   type: com.zaxxer.hikari.HikariDataSource
   slave:
   username: root
   password: 12345678
   url: jdbc:mysql://localhost:3306/zeroStart?characterEncoding=UTF-8&useSSL=true&requireSSL=false&zeroDateTimeBehavior=convertToNull&useSSL=false&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=Asia/Shanghai&allowMultiQueries=true
   driver-class-name: com.mysql.cj.jdbc.Driver
   type: com.zaxxer.hikari.HikariDataSource8、引入的依赖
   <dependency>
         <groupId>com.baomidou</groupId>
         <artifactId>dynamic-datasource-spring-boot-starter</artifactId>
         <version>2.4.2</version>
   </dependency>
   <dependency>
         <groupId>com.baomidou</groupId>
         <artifactId>mybatis-plus-extension</artifactId>
         <version>${mybatis-plus.version}</version>
   </dependency>

   <dependency>
         <groupId>com.alibaba</groupId>
         <artifactId>druid</artifactId>
         <version>1.2.7</version>
   </dependency>

   <dependency>
         <groupId>com.alibaba</groupId>
         <artifactId>druid-spring-boot-starter</artifactId>
         <version>1.2.16</version>
   </dependency>配置到这就好了，业务代码就不展示了

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零基础尝试mybatis-plus读写分离