hive 将hive表数据查询出来转为json对象和json数组输出
一、将hive表数据查询出来转为json对象输出
1、将查询出来的数据转为一行一行,并指定分割符的数据
2、使用UDF函数,将每一行数据作为string传入UDF函数中转换为json再返回
1、准备数据
2、查询出来的数据转为一行一行,并指定分割符的数据
3、准备UDF函数
package com.laotou; import org.apache.hadoop.hive.ql.exec.UDF; import org.json.JSONException; import org.json.JSONObject; /** * @Author: * @Date: 2019/8/9 */ public class HiveJsonOut extends UDF{public static String evaluate(String jsonStr) throws JSONException { String[] split = jsonStr.split(","); JSONObject result = new JSONObject(); result.put("key", split[0]); result.put("value", split[1]); return String.valueOf(result); } }
package com.laotou; import org.apache.hadoop.hive.ql.exec.UDF; import org.json.JSONException; import org.json.JSONObject; /** * @Author: * string转json:{"notifyType":13,"notifyEntity":{"school":"小学","name":"张三","age":"13"}} * @Date: 2019/8/14 */ public class Record2Notify extends UDF { private static final String split_char = "!"; private static final String null_char = "\002"; public static String evaluate(int type, String line) throws JSONException { if (line == null) { return null; } JSONObject notify = new JSONObject(); JSONObject entity = new JSONObject(); notify.put("notifyType", type); String[] columns = line.split(split_char, -1); int size = columns.length / 2; for (int i = 0; i < size; i++) { String key = columns[i*2]; String value = columns[i*2+1]; if (isNull(key)) { throw new JSONException("Null key.1111111111"); } if (!isNull(value)) { entity.put(key, value); } } notify.put("notifyEntity", entity); return notify.toString(); } private static boolean isNull(String value) { return value == null || value.isEmpty() || value.equals(null_char); } public static void main(String[] args) throws JSONException { System.out.println(evaluate(13,"name!张三!age!13!school!小学")); } }
二、将hive表数据查询出来转为json数组输出
思路:
1、使用UDF函数(见上面内容)将查询出来的每一条数据转成json对象
select getJsonOut(concat_ws(',',key,value)) as content from test1
2、将第一步查询的结果进行列转行,并设置为逗号进行分割,得到如下字符串
select concat_ws('!!',collect_list(bb.content)) as new_value from (select getJsonOut(concat_ws(',',key,value)) as content from test1) bb;
结果如图:
3、使用UDF函数(JsonArray)将第2步中得到的字符串放入数组对象,准备UDF函数
package com.laotou;
import org.apache.hadoop.hive.ql.exec.UDF;
import org.json.JSONArray;
import org.json.JSONException;
/**
* create temporary function getJsonArray as 'com.laotou.HiveJson';
* @Author:
* @Date: 2019/8/9
*/
public class HiveJson extends UDF{
public static JSONArray evaluate(String jsonStr) throws JSONException {
String[] split = jsonStr.split("!!");
JSONArray jsonArray = new JSONArray();
jsonArray.put(split[0]);
jsonArray.put(split[1]);
jsonArray.put(split[2]);
jsonArray.put(split[3]);
return jsonArray;
}
}
4、测试
select getJsonArray(new_value) from (select cast(concat_ws('!!',collect_list(bb.content)) as string) as new_value from (select getJsonOut(concat_ws(',',key,value)) as content from test1) bb) cc;