JDBC写入postgresql json格式出现以下错误：

Caused by: org.postgresql.util.PSQLException: ERROR: column "stu_json" is of type json but expression is of type character varying
  建议：You will need to rewrite or cast the expression.

解决方案：

在连接参数中加入：&stringtype=unspecified

用于把JSON类型当STRING类型存储

或者使用PGobject对象来传输

PGobject pgobject = new PGobject();
pgobject.setType("json");
pgobject.setValue(jsonString);