Python工程师Java之路（r）把字符串转成JSON

Posted 2022-04-19 小基基o_O

文章目录

• 概述
• 使用fastjson，把字符串转成JSON
• • Java版
  • Scala版
  • Spark版

概述

• JSON(javascript Object Notation, JS 对象简谱)
  是一种轻量级的数据交换格式
  采用完全独立于编程语言的文本格式来存储和表示数据

使用fastjson，把字符串转成JSON

MAVEN依赖

<properties>
    <fastjson.version>1.2.47</fastjson.version>
</properties>

<dependencies>
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>fastjson</artifactId>
        <version>$fastjson.version</version>
    </dependency>
</dependencies>

Java版

import com.alibaba.fastjson.JSONObject;

public class JsonDemo 
    public static void main(String[] args) 
        // 字符串->JSON
        String s = "\\"b\\": \\"BB\\",\\"c\\":\\"cc\\":43 ";
        JSONObject j = JSONObject.parseObject(s);
        // 打印
        System.out.println(s);
        // "b": "BB","c":"cc":43 
        System.out.println(j);
        // "b":"BB","c":"cc":43
        System.out.println(j.getClass());
        // class com.alibaba.fastjson.JSONObject
        System.out.println(j.getString("b"));
        // BB
        System.out.println(j.getJSONObject("c").getInteger("cc"));
        // 43
    

Scala版

import com.alibaba.fastjson.JSON, JSONObject

object JsDemo 
  def main(args: Array[String]): Unit = 
    // 字符串->JSON
    val s: String = "\\"b\\": \\"BB\\",\\"c\\":\\"cc\\":43 "
    val b: JSONObject = JSON.parseObject(s)
    // 打印
    println(s)
    // "b": "BB","c":"cc":43 
    println(b.getClass)
    // class com.alibaba.fastjson.JSONObject
    println(b)
    // "b":"BB","c":"cc":43
    println(b.getString("b"))
    // BB
    println(b.getJSONObject("c").getInteger("cc"))
    // 43
  

Spark版

pom.xml

<dependencies>
    <dependency>
        <groupId>org.apache.spark</groupId>
        <artifactId>spark-core_2.12</artifactId>
        <version>3.0.0</version>
    </dependency>
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>fastjson</artifactId>
        <version>1.2.47</version>
    </dependency>
</dependencies>

SparkDemo.scala

import com.alibaba.fastjson.JSON, JSONObject
import org.apache.spark.SparkConf, SparkContext
import org.apache.spark.rdd.RDD

case class UP(user_id: String, page_id: String, timestamp: BigInt, hms: String)

object SparkDemo 
  def main(args: Array[String]): Unit = 
    // 创建SparkContext
    val c0: SparkConf = new SparkConf().setAppName("a0").setMaster("local[2]")
    val sc: SparkContext = new SparkContext(c0)
    // 读数据
    val r: RDD[String] = sc.textFile("src/main/resources/a.txt")
    // JSON解析
    val js: RDD[UP] = r.map 
      line =>
        val j: JSONObject = JSON.parseObject(line)
        UP(
          j.getString("user_id"),
          j.getString("page_id"),
          j.getBigInteger("timestamp"),
          j.getString("hms"),
        )
    
    js.foreach(println)
  

a.txt

"user_id": "u102", "page_id": "p7", "timestamp": 1649997187106, "hms": "2022-04-15 12:33:07"
"user_id": "u0", "page_id": "p7", "timestamp": 1649997307206, "hms": "2022-04-15 12:35:07"
"user_id": "u216", "page_id": "p6", "timestamp": 1649997427304, "hms": "2022-04-15 12:37:07"
"user_id": "u51", "page_id": "p7", "timestamp": 1649997547403, "hms": "2022-04-15 12:39:07"
"user_id": "u75", "page_id": "p6", "timestamp": 1649997667504, "hms": "2022-04-15 12:41:07"
"user_id": "u53", "page_id": "p3", "timestamp": 1649997787603, "hms": "2022-04-15 12:43:07"
"user_id": "u93", "page_id": "p8", "timestamp": 1649997907704, "hms": "2022-04-15 12:45:07"
"user_id": "u119", "page_id": "p5", "timestamp": 1649998027803, "hms": "2022-04-15 12:47:07"
"user_id": "u177", "page_id": "p7", "timestamp": 1649998147902, "hms": "2022-04-15 12:49:07"