运用Mybatis动态查询字段及表名

Mapper.java

IPage<Map<String, Object>> getDyData(@Param("page") Page page, @Param("columns")String columns, @Param("tableName")String tableName);

Mapper.xml

<select id="getDyData" resultType="java.util.Map">
select 
     ${columns}
from 
    ${tableName}  dy
</select>

使用场景：

1.我们必须知道查询的表名，可以通过表名查询字段及注释，然后把表名和字段传进mapper

2.如果知道具体查询哪些表，可以把这些表及表对应的字段配置进一张表和字段对应的表中，通过表名查询该表取出对应的字段及注释，此处的字段注释可以自己写相对比较灵活。

DROP TABLE IF EXISTS `table_colume_mapping`;
CREATE TABLE `table_colume_mapping`  (
  `table_name` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL COMMENT '表名',
  `column_name` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL COMMENT '字段名',
  `column_comment` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL COMMENT '字段汉语名',
  `table_comment` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL COMMENT '表名注释',
  `sort` int(10) NULL DEFAULT NULL COMMENT '字段排序',
  `show_column` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT '是' COMMENT '是否展示在列',
  `del_flag` char(1) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT '0' COMMENT '0存在1删除'
) ENGINE = InnoDB CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci COMMENT = '表字段注释映射' ROW_FORMAT = Dynamic;

SET FOREIGN_KEY_CHECKS = 1;

调用

LambdaQueryWrapper<TableColumeMapping> wrapper = new LambdaQueryWrapper<>();
			wrapper.eq(TableColumeMapping::getTableName, "查询的表名");
			List<TableColumeMapping> list = SpringContextHolder.getBean(TableColumeMapping.class).list(wrapper);
Map<String, TableColumeMapping> tableColumeMap = list.stream().collect(Collectors.toMap(TableColumMapperPerson::getColumnName, account -> account));
String columnNames = list.stream().map(item -> "dy."+item.getColumnName()).collect(Collectors.joining(","));
IPage<Map<String, Object>> result = this.baseMapper.getDyData(page,columnNames,"查询的表名");