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;
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