Spring Boot集成MyBatis-Plus 自定义拦截器实现动态表名切换功能

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>最新版本号</version>
</dependency>

@Component
@Intercepts({@Signature(type = StatementHandler.class, method = "prepare", args = {Connection.class, Integer.class})})
public class DynamicTableInterceptor implements Interceptor {
  	/**
     * 使用ThreadLocal来存储线程特有的数据，这里用于存储动态表名
     */
    private static final ThreadLocal<String> TABLE_NAME_HOLDER = new ThreadLocal<>();
    /**
     * 设置动态表名
     *
     * @param tableName 需要设置的表名，由调用者指定
     *                  此方法允许在运行时动态地设置数据库表名，以便在多数据源或动态表名的场景下灵活地切换表
     */
    public static void setDynamicTableName(String tableName) {
        TABLE_NAME_HOLDER.set(tableName);
    }
    /**
     * 清除当前线程中的动态表名
     * 此方法用于清除ThreadLocal中存储的表名信息，以避免内存泄漏
     * 它应在每次使用动态表名后调用，确保不会对后续的请求产生影响
     */
    public static void clearDynamicTableName() {
        TABLE_NAME_HOLDER.remove();
    }
    /**
     * 拦截器
     */
    @Override
    public Object intercept(Invocation invocation) throws Throwable {
        StatementHandler handler = (StatementHandler) invocation.getTarget();
        BoundSql boundSql = handler.getBoundSql();
        String tableName = TABLE_NAME_HOLDER.get();
        if (tableName != null) {
            /**
             * 从实体类的@tableName中获取表名，必须在实体类上面添加@tableName注解
             * 实体类中的@tableName注解中的值，必须是数据库中的表名，否则会报错
             * 例如 ：@TableName("t_user_")，数据库是根据月份来的，在这里替换则需要根据当前月份进行拼接表名
             */
            Class<?> entityType = boundSql.getParameterObject().getClass();
            String oldTableName = entityType.getAnnotation(TableName.class).value();
            String newSql = boundSql.getSql().replace(oldTableName, tableName);
            Field sqlField = boundSql.getClass().getDeclaredField("sql");
            sqlField.setAccessible(true);
            sqlField.set(boundSql, newSql);
        }
        return invocation.proceed();
    }
}

DynamicTableInterceptor.setDynamicTableName("your_dynamic_table_name");
try {
    myService.saveOrUpdateBatch(entities); // MyBatis-Plus 操作
} finally {
    DynamicTableInterceptor.clearDynamicTableName();
}

@Override
public Object intercept(Invocation invocation) throws Throwable {
    StatementHandler handler = (StatementHandler) invocation.getTarget();
    BoundSql boundSql = handler.getBoundSql();
    long startTime = System.currentTimeMillis();
    Object result = invocation.proceed();
    long endTime = System.currentTimeMillis();
    System.out.println("SQL: " + boundSql.getSql() + " Execution Time: " + (endTime - startTime) + "ms");
    return result;
}

@Override
public Object intercept(Invocation invocation) throws Throwable {
    StatementHandler handler = (StatementHandler) invocation.getTarget();
    BoundSql boundSql = handler.getBoundSql();
    String originalSql = boundSql.getSql();
    String tenantId = TenantContext.getCurrentTenantId();
    String modifiedSql = originalSql + " WHERE tenant_id = " + tenantId;
    Field sqlField = boundSql.getClass().getDeclaredField("sql");
    sqlField.setAccessible(true);
    sqlField.set(boundSql, modifiedSql);
    return invocation.proceed();
}

@Override
public Object intercept(Invocation invocation) throws Throwable {
    StatementHandler handler = (StatementHandler) invocation.getTarget();
    BoundSql boundSql = handler.getBoundSql();
    String sql = boundSql.getSql();
    // 自定义加密逻辑
    // 加密处理参数
    return invocation.proceed();
}

@Override
public Object intercept(Invocation invocation) throws Throwable {
    StatementHandler handler = (StatementHandler) invocation.getTarget();
    BoundSql boundSql = handler.getBoundSql();
    String originalSql = boundSql.getSql();
    String paginatedSql = originalSql + " LIMIT " + offset + ", " + limit;
    Field sqlField = boundSql.getClass().getDeclaredField("sql");
    sqlField.setAccessible(true);
    sqlField.set(boundSql, paginatedSql);
    return invocation.proceed();
}

@Override
public Object intercept(Invocation invocation) throws Throwable {
    StatementHandler handler = (StatementHandler) invocation.getTarget();
    BoundSql boundSql = handler.getBoundSql();
    String originalSql = boundSql.getSql();
    String userRole = SecurityContext.getCurrentUserRole();
    String restrictedSql = originalSql + " AND role = '" + userRole + "'";
    // 动态修改 SQL
    return invocation.proceed();
}

@Override
public Object intercept(Invocation invocation) throws Throwable {
    // 检查缓存
    Object cachedResult = CacheManager.get(boundSql.getSql());
    if (cachedResult != null) {
        return cachedResult;
    }
    // 如果没有命中，执行查询
    Object result = invocation.proceed();
    // 存入缓存
    return result;
}

@Override
public Object intercept(Invocation invocation) throws Throwable {
    String dataSourceKey = DataSourceContextHolder.getDataSourceKey();
    DynamicDataSource.setDataSourceKey(dataSourceKey);
    return invocation.proceed();
}