Select强制走主库

走主库标志位

/**
 * 读数据走主库工具类
 *
 * @author 木杉
 * @classname MybatisMasterRouteUtils
 * @date 2023/2/10 9:20
 */
public final class MybatisMasterRouteUtils {

    private MybatisMasterRouteUtils(){}

    /**
     * 本地线程
     */
    private final static ThreadLocal<Boolean> threadLocal = new ThreadLocal<>();

    /**
     * 从主库读取数据
     *
     * @methodName activityReadMasterRoute
     * @date 2023/2/10 9:23
     * @author 木杉
     */
    public static void activityReadMasterRoute(){
        threadLocal.set(true);
    }

    /**
     * 获取是否读主库状态
     *
     * @methodName getReadMasterRoute
     * @date 2023/2/10 9:25
     * @author 木杉
     */
    public static Boolean getReadMasterRoute(){
        Boolean flag = threadLocal.get();
        flag = (flag == null ? false : flag);
        return flag;
    }

    /**
     * 停止从主库读取数据
     *
     * @methodName stopReadMasterRoute
     * @date 2023/2/10 9:23
     * @author 木杉
     */
    public static void stopReadMasterRoute(){
        threadLocal.remove();
    }
}

Mybatis拦截器工具类

import org.apache.ibatis.mapping.BoundSql;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.SqlSource;
import org.apache.ibatis.plugin.Invocation;
import org.apache.ibatis.reflection.DefaultReflectorFactory;
import org.apache.ibatis.reflection.MetaObject;
import org.apache.ibatis.reflection.factory.DefaultObjectFactory;
import org.apache.ibatis.reflection.wrapper.DefaultObjectWrapperFactory;

/**
 * Mybatis拦截器工具类
 *
 * @author 木杉
 * @classname MybatisInterceptorUtils
 * @date 2023/2/10 9:11
 */
public final class MybatisInterceptorUtils {

    private static int MAPPED_STATEMENT_INDEX = 0;
    private static int PARAMETER_INDEX = 1;
    private static int ROWBOUNDS_INDEX = 2;
    private static int RESULT_HANDLER_INDEX = 3;

    private MybatisInterceptorUtils(){}

    /**
     * 获取sql语句
     * @param invocation
     * @return
     */
    public static String getSqlByInvocation(Invocation invocation) {
        final Object[] args = invocation.getArgs();
        MappedStatement ms = (MappedStatement) args[MAPPED_STATEMENT_INDEX];
        Object parameterObject = args[PARAMETER_INDEX];
        BoundSql boundSql = ms.getBoundSql(parameterObject);
        return boundSql.getSql();
    }

    /**
     * 包装sql后，重置到invocation中
     * @param invocation
     * @param sql
     */
    public static Invocation resetSql2Invocation(Invocation invocation, String sql) {
        final Object[] args = invocation.getArgs();

        MappedStatement statement = (MappedStatement) args[MAPPED_STATEMENT_INDEX];
        Object parameterObject = args[PARAMETER_INDEX];
        BoundSql boundSql = statement.getBoundSql(parameterObject);
        MappedStatement newStatement = newMappedStatement(statement, new MybatisInterceptorUtils.BoundSqlSqlSource(boundSql));
        MetaObject msObject =  MetaObject.forObject(newStatement, new DefaultObjectFactory(), new DefaultObjectWrapperFactory(),new DefaultReflectorFactory());
        msObject.setValue("sqlSource.boundSql.sql", sql);
        args[MAPPED_STATEMENT_INDEX] = newStatement;

        return invocation;
    }

    private static MappedStatement newMappedStatement(MappedStatement ms, SqlSource newSqlSource) {
        MappedStatement.Builder builder =
                new MappedStatement.Builder(ms.getConfiguration(), ms.getId(), newSqlSource, ms.getSqlCommandType());
        builder.resource(ms.getResource());
        builder.fetchSize(ms.getFetchSize());
        builder.statementType(ms.getStatementType());
        builder.keyGenerator(ms.getKeyGenerator());
        if (ms.getKeyProperties() != null && ms.getKeyProperties().length != 0) {
            StringBuilder keyProperties = new StringBuilder();
            for (String keyProperty : ms.getKeyProperties()) {
                keyProperties.append(keyProperty).append(",");
            }
            keyProperties.delete(keyProperties.length() - 1, keyProperties.length());
            builder.keyProperty(keyProperties.toString());
        }
        builder.timeout(ms.getTimeout());
        builder.parameterMap(ms.getParameterMap());
        builder.resultMaps(ms.getResultMaps());
        builder.resultSetType(ms.getResultSetType());
        builder.cache(ms.getCache());
        builder.flushCacheRequired(ms.isFlushCacheRequired());
        builder.useCache(ms.isUseCache());
        return builder.build();
    }

    /**
     * 内部辅助类，包装sql
     */
    static class BoundSqlSqlSource implements SqlSource {
        private BoundSql boundSql;
        public BoundSqlSqlSource(BoundSql boundSql) {
            this.boundSql = boundSql;
        }
        @Override
        public BoundSql getBoundSql(Object parameterObject) {
            return boundSql;
        }
    }
}

Mybatis拦截器

import lombok.extern.slf4j.Slf4j;
import org.apache.ibatis.cache.CacheKey;
import org.apache.ibatis.executor.Executor;
import org.apache.ibatis.mapping.BoundSql;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.plugin.Interceptor;
import org.apache.ibatis.plugin.Intercepts;
import org.apache.ibatis.plugin.Invocation;
import org.apache.ibatis.plugin.Signature;
import org.apache.ibatis.session.ResultHandler;
import org.apache.ibatis.session.RowBounds;
import org.springframework.stereotype.Component;

import java.util.Properties;

/**
 * mysql拦截器
 *
 * @author 木杉
 * @classname MybatisMasterQueryInterceptor
 * @date 2023/2/9 15:23
 */
@Intercepts({
        @Signature(type = Executor.class, method = "query", args = {MappedStatement.class, Object.class,
                RowBounds.class, ResultHandler.class, CacheKey.class, BoundSql.class})})
@Slf4j
@Component
public class MybatisInterceptor implements Interceptor {

    /**
     * 主库标识
     */
    private final static String MASTER_ROUTE_FLAG = "/*master*/";

    @Override
    public Object intercept(Invocation invocation) throws Throwable {

        if (MybatisMasterRouteUtils.getReadMasterRoute()) {
            //当前query是否读主库
            //获取sql语句
            String sql = MybatisInterceptorUtils.getSqlByInvocation(invocation);
            sql = MASTER_ROUTE_FLAG + sql;
            MybatisInterceptorUtils.resetSql2Invocation(invocation, sql);
        }
        return invocation.proceed();
    }

    @Override
    public Object plugin(Object target) {
        return Interceptor.super.plugin(target);
    }

    @Override
    public void setProperties(Properties properties) {
        Interceptor.super.setProperties(properties);
    }

}

切面

import java.lang.annotation.*;

/**
 * 读数据强制走主库
 *
 * @author 木杉
 * @classname MyBatisReadMasterRoute
 * @date 2023/2/13 17:47
 */
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD})
@Documented
public @interface MyBatisReadMasterRoute {
}

import lombok.extern.slf4j.Slf4j;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.springframework.stereotype.Component;

/**
 * 读数据强制走主库切面
 *
 * @author 木杉
 * @classname UserCheckAspect
 * @date 2022/11/21 17:05
 */
@Aspect
@Slf4j
@Component
public class MybatisReadMasterRouteAspectAspect {
    @Around("@annotation(myBatisReadMasterRoute)")
    public Object checkUser(ProceedingJoinPoint point, MyBatisReadMasterRoute myBatisReadMasterRoute) throws Throwable {
        MybatisMasterRouteUtils.activityReadMasterRoute();
        Object proceed = null;
        try {
            proceed = point.proceed();
        } finally {
            MybatisMasterRouteUtils.stopReadMasterRoute();
        }
        return proceed;
    }
}

示例

LevelUser levelUser = null;
        try {
            MybatisMasterRouteUtils.activityReadMasterRoute();
            //主从库存在同步延迟问题 所以这里走主库查询防止插入多条数据
            LambdaQueryWrapper<LevelUser> queryWrapper = Wrappers.lambdaQuery();
            queryWrapper.eq(LevelUser::getUserId, userId)
                    .eq(LevelUser::getDelFlag, LevelUserDelEnums.NORMAL.getDelFlag());
            levelUser = levelUserService.getOne(queryWrapper);
        } finally {
            MybatisMasterRouteUtils.stopReadMasterRoute();
        }

一定要finally，防止报错后标志位没有修改，该线程随后的sql操作都会走主库