@PostMapping(value = "/show/databases")
    public AjaxResult showDatabases(@RequestBody DataSourceTo to) {
        SqlSession session = connDataBase(to);
        String key = dataSourceMemoryHandler.createKey(to);
        if (session == null) {
            return error("连接数据库失败");
        }
        //logger.info(key);
        List<String> resultList = dbsService.showDatabases(session);
        return success(key).put("databases", resultList);
    }

    @PostMapping(value = "/show/tables")
    public AjaxResult showTables(@RequestBody String key) {
        SqlSession session = connDataBase(key);
        if (session == null) {
            return error("连接数据库失败");
        }
        List<TableInfoVo> resultList = dbsService.showTables(session);
        return success(resultList);
    }

    @PostMapping(value = "/show/columns/{tableName}")
    public AjaxResult showColumns(@RequestBody String key, @PathVariable("tableName") String tableName) {
        SqlSession session = connDataBase(key);
        if (session == null) {
            return error("连接数据库失败");
        }
        List<ColumnInfo> resultList = dbsService.showColumns(session, tableName);
        return success(resultList);
    }

    @PostMapping(value = "/save/querycode")
    public AjaxResult saveQueryCode(@RequestBody QueryCodeTo to) {
        to.setCreateTime(new Date());

        QueryCodeEntity queryCode = YisooBeanUtils.copyProperties(to, QueryCodeEntity.class);

        queryCodeService.insert(queryCode);

        return success("ok");
    }

   Make sure to only use capital letters in your entire response.
user