json存数据库时处理器，jsonHandler/jsonArrayHandler

class ObjectJsonHandler<T> extends BaseTypeHandler<T> { private Class<T> clazz; 　　

　　 /**构造函数*/ public ObjectJsonHandler(Class<T> clazz) { if (clazz == null ) { throw new IllegalArgumentException("Type argument cannot be null" ); } this .clazz = clazz; } private NameFilter nameFilter = (object, name, value) -> name; /** * 设置非空参数 */ @Override public void setNonNullParameter(PreparedStatement ps, int i, T parameter, JdbcType jdbcType) throws SQLException { ps.setString(i, JSON.toJSONString(parameter, nameFilter)); } /** * 根据列名，获取可以为空的结果 */ @Override public T getNullableResult(ResultSet rs, String columnName) throws SQLException { String sqlJson = rs.getString(columnName); if ( null != sqlJson) { return JSONObject.parseObject(sqlJson, clazz); } return null ; } /** * 根据列索引，获取可以为空的结果 */ @Override public T getNullableResult(ResultSet rs, int columnIndex) throws SQLException { String sqlJson = rs.getString(columnIndex); if ( null != sqlJson) { return JSONObject.parseObject(sqlJson, clazz); } return null ; } @Override public T getNullableResult(CallableStatement cs, int columnIndex) throws SQLException { String sqlJson = cs.getString(columnIndex); if ( null != sqlJson) { return JSONObject.parseObject(sqlJson, clazz); } return null ; } }

2、继承ObjectJsonHandler

 /**  
 * @Author jijiecong
 * @Date 2021/4/20 11:49
 * @Version 1.0
 * @Description 评价扩展字段json处理器
   */ 
 public   class  EvaluationAttributesJsonHandler  extends  ObjectJsonHandler<EvaluationAttributesEntity>  {

      public   EvaluationAttributesJsonHandler() {
          super (EvaluationAttributesEntity. class  );
    }

} 

 

二、List对象转JsonArray

1、继承BaseTypeHandler

覆盖setNonNullParameter()，getNullableResult()，getNullableResult()，getNullableResult()方法

**
 *  ObjectJsonArrayHandler
  *  JSONArray处理类
  *
 * @version v1.0.0
 * @date 2020/7/23
 */
 public   class  ObjectJsonArrayHandler<T>   extends  BaseTypeHandler<List<T>>  {

      private   final  Class<T>  clazz;

      public  ObjectJsonArrayHandler(Class<T>  clazz) {
          if  (clazz ==  null  ) {
              throw   new  IllegalArgumentException("Type argument cannot be null" );
        }   else   {
              this .clazz =  clazz;
        }
    }

    @Override
      public   void  setNonNullParameter(PreparedStatement ps,  int  i, List<T> ts, JdbcType jdbcType)  throws   SQLException {
        ps.setString(i, JSONArray.toJSONString(ts));
    }

    @Override
      public  List<T> getNullableResult(ResultSet rs, String s)  throws   SQLException {
        String jsonArrayStr  =  rs.getString(s);
          if  ( null  !=  jsonArrayStr) {
              return   JSONArray.parseArray(jsonArrayStr).toJavaList(clazz);
        }
          return   null  ;
    }

    @Override
      public  List<T> getNullableResult(ResultSet rs,  int  i)  throws   SQLException {
        String jsonArrayStr  =  rs.getString(i);
          if  ( null  !=  jsonArrayStr) {
              return   JSONArray.parseArray(jsonArrayStr).toJavaList(clazz);
        }
          return   null  ;
    }

    @Override
      public  List<T> getNullableResult(CallableStatement cs,  int  i)  throws   SQLException {
        String jsonArrayStr  =  cs.getString(i);
          if  ( null  !=  jsonArrayStr) {
              return   JSONArray.parseArray(jsonArrayStr).toJavaList(clazz);
        }
          return   null  ;
    }
} 

2、继承ObjectJsonArrayHandler

 /**  
 * StringJsonArrayHandler
 *
 *   @version   v1.0.0
 * @date 2020/8/11
   */ 
 public   class  StringJsonArrayHandler  extends  ObjectJsonArrayHandler<String>  {

      public  StringJsonArrayHandler(Class<String>  clazz) {
          super (String. class  );
    }
} 

 

json存数据库时处理器，jsonHandler/jsonArrayHandler

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