Oracle编写解析字段为json字符串的函数

建立如下两种类型：

create or replace 
TYPE ty_row_str_split  as object (strValue VARCHAR2 (4000));

create or replace 
TYPE ty_tbl_str_split AS TABLE OF ty_row_str_split;

建立如下两种函数：

create or replace 
FUNCTION fn_split(p_str       IN VARCHAR2,
                                    p_delimiter IN VARCHAR2)
  RETURN ty_tbl_str_split IS
  j         INT := 0;
  i         INT := 1;
  len       INT := 0;
  len1      INT := 0;
  str       VARCHAR2(4000);
  str_split ty_tbl_str_split := ty_tbl_str_split();
BEGIN
  len  := LENGTH(p_str);
  len1 := LENGTH(p_delimiter);

  WHILE j < len LOOP
    j := INSTR(p_str, p_delimiter, i);

    IF j = 0 THEN
      j   := len;
      str := SUBSTR(p_str, i);
      str_split.EXTEND;
      str_split(str_split.COUNT) := ty_row_str_split(strValue => str);

      IF i >= len THEN
        EXIT;
      END IF;
    ELSE
      str := SUBSTR(p_str, i, j - i);
      i   := j + len1;
      str_split.EXTEND;
      str_split(str_split.COUNT) := ty_row_str_split(strValue => str);
    END IF;
  END LOOP;

  RETURN str_split;
END fn_split;

create or replace 
FUNCTION parsejson(p_jsonstr varchar2,p_key varchar2) RETURN VARCHAR2
AS
  rtnVal VARCHAR2(1000);
  i NUMBER(2);
  jsonkey VARCHAR2(500);
  jsonvalue VARCHAR2(1000);
  json VARCHAR2(3000);
BEGIN
  IF p_jsonstr IS NOT NULL THEN
     json := REPLACE(p_jsonstr,'{','') ;
     json := REPLACE(json,'}','') ;
     json := replace(json,'"','') ;
     FOR temprow IN(SELECT strvalue AS VALUE FROM TABLE(fn_split(json, ','))) LOOP
        IF temprow.VALUE IS NOT NULL THEN
           i := 0;
           jsonkey := '';
           jsonvalue := '';
           FOR tem2 IN(SELECT strvalue AS VALUE FROM TABLE(fn_split(temprow.value, ':'))) LOOP
               IF i = 0 THEN
                  jsonkey := tem2.VALUE;
               END IF;
               IF i = 1 THEN
                  jsonvalue := tem2.VALUE;
               END IF;

               i := i + 1;
           END LOOP;

           IF(jsonkey = p_key) THEN
               rtnVal := jsonvalue;
           END if;
        END IF;
     END LOOP;
  END IF;
  RETURN rtnVal;
END parsejson;

编写测试：

select parsejson('{"name":"huangbaokang","age":20}','name') from dual