FastJson簡介
FastJson三個核心類
Maven
Java API
反序列化一個簡單Json字符串
反序列化一個簡單JSON字符串成Java對象組
反序列化一個復(fù)雜的JSON字符串
反序列化
序列化
序列化和反序列化日期
JsonObject的一些操作
jsonArray的一些操作
Scala API
demo日志內(nèi)容
反序列化簡單json字符串
反序列化簡單json字符串組
String處理
List處理
反序列化
JSON協(xié)議在日常開發(fā)中很常用，包括前后端的數(shù)據(jù)接口，日志字段的保存等，通常都采用JSON協(xié)議。FastJson是阿里的開源框架，很好用，估計(jì)開發(fā)的同學(xué)都有使用過。這里做一個簡單的用法總結(jié)，配一些demo。除了Java版本外，由于在Spark也經(jīng)常清洗日志，所以配上了Scala版本，方便日后查詢使用。完整代碼可以參考Github:https://github.com/tygxy/BigData
JSON：fastjson的解析器，用于json字符串和javaBean、Json對象的轉(zhuǎn)換
JSONObject：fastJson提供的json對象
JSONArray：fastJson提供json數(shù)組對象
com.alibaba fastjson 1.2.47
反序列化一個簡單Json字符串
重慶分公司
重慶分公司
public class User {
private String name; private int age; public String getName() { return name;
} public void setName(String name) { this.name = name;
} public int getAge() { return age;
} public void setAge(int age) { this.age = age;
}
}String jsonString = "{\"name\":\"張三\",\"age\":50}";
User user= JSON.parseObject(jsonString,User.class);
System.out.println("name:"+user.getName()+" age:"+user.getAge());// 輸出結(jié)果 name:張三 age:50反序列化操作
創(chuàng)建JavaBean的User類
反序列化一個簡單JSON字符串成Java對象組
String jsonArrayString = "[{\"name\":\"張三\",\"age\":50},{\"name\":\"李四\",\"age\":51}]";
List userList = JSON.parseArray(jsonArrayString,User.class);
Iterator it = userList.iterator();while (it.hasNext()) {
User u = (User)it.next();
System.out.println("name:"+u.getName()+" age:"+u.getAge());
}// 輸出結(jié)果 name:張三 age:50
name:李四 age:51 反序列化一個復(fù)雜的JSON字符串
public class Course { private String courseName; private String code; public Course (String courseName, String code){ this.setCourseName(courseName); this.setCode(code);
} public String getCourseName() { return courseName;
} public void setCourseName(String courseName) { this.courseName = courseName;
} public String getCode() { return code;
} public void setCode(String code) { this.code = code;
}
}public class Student { private int id; private String studentName; private int age; public Student(int id, String studentName, int age) { this.setId(id); this.setStudentName(studentName); this.setAge(age);
} public int getId() { return id;
} public void setId(int id) { this.id = id;
} public String getStudentName() { return studentName;
} public void setStudentName(String studentName) { this.studentName = studentName;
} public int getAge() { return age;
} public void setAge(int age) { this.age = age;
}
}public class Teacher { private String teacherName; private int age; private Course course; private List students; public Teacher(String teacherName, int age, Course course, List students) { this.setTeacherName(teacherName); this.setAge(age); this.setCourse(course); this.setStudents(students);
} public String getTeacherName() { return teacherName;
} public void setTeacherName(String teacherName) { this.teacherName = teacherName;
} public int getAge() { return age;
} public void setAge(int age) { this.age = age;
} public Course getCourse() { return course;
} public void setCourse(Course course) { this.course = course;
} public List getStudents() { return students;
} public void setStudents(List students) { this.students = students;
}
} String complexJsonString = "{\"teacherName\":\"crystall\",\"age\":27,\"course\":{\"courseName\":\"english\",\"code\":1270},\"students\":[{\"id\":1,\"studentName\":\"lily\",\"age\":12},{\"id\":2,\"studentName\":\"lucy\",\"age\":15}]}";
Teacher teacher = JSON.parseObject(complexJsonString,Teacher.class);反序列化操作
分別創(chuàng)建JavaBean的Course類、Student類、Teacher類
序列化一個Java Bean對象
User u = new User();
u.setName("王五");
u.setAge(30);
System.out.println(JSON.toJSONString(u));// 輸出結(jié)果 {"age":30,"name":"王五"}
User u1 = new User();
u1.setAge(30);
System.out.println(JSON.toJSONString(u1,SerializerFeature.WriteMapNullValue)); // 輸出null，輸出結(jié)果 {"age":30,"name":null}
System.out.println(JSON.toJSONString(u1,SerializerFeature.WriteNullStringAsEmpty)); // 輸出""，輸出結(jié)果 {"age":30,"name":""}Date date = new Date();String dateString = JSON.toJSONStringWithDateFormat(date, "yyyy-MM-dd HH:mm:ss");
System.out.println(dateString);// 輸出結(jié)果 "2018-08-03 09:44:21"String dateString1 = "{\"time\":\"2018-08-01 22:22:22\"}";
System.out.println(JSON.parseObject(dateString1));// 輸出結(jié)果 {"time":"2018-08-01 22:22:22"}String jsonString1 = "{\"name\":\"張三\",\"age\":50}";
JSONObject jsonObject = JSON.parseObject(jsonString1);
System.out.println(jsonObject.keySet()); // 輸出key集合，輸出結(jié)果 [name, age]if(jsonObject.containsKey("sex")) { // 判斷key是否存在，輸出結(jié)果 false
System.out.println(true);
} else {
System.out.println(false);
}
jsonObject.put("sex","man"); // 添加k/v鍵值對，輸出結(jié)果 {"sex":"man","name":"張三","age":50}
System.out.println(jsonObject);if (jsonObject.containsValue("man")) { // 判斷value是否存在，輸出結(jié)果 false
System.out.println(true);
} else {
System.out.println(false);
}String jsonArrayString1 = "[{\"id\":1,\"studentName\":\"lily\",\"age\":12},{\"id\":2,\"studentName\":\"lucy\",\"age\":15}]";
JSONArray jsonArray = JSON.parseArray(jsonArrayString1);for (int i = 0; i < jsonArray.size(); i++) { // 遍歷輸出
JSONObject jsonObj= jsonArray.getJSONObject(i);
System.out.println(jsonObj.get("id"));
}
Student s3 = new Student(3,"學(xué)生乙",15);
jsonArray.add(s3); // 添加新jsonobject對象，輸出結(jié)果 3System.out.println(jsonArray.size());if(jsonArray.contains(s3)) { // 判斷是否存在，輸出結(jié)果 true
System.out.println(true);
} else {
System.out.println(false);
}demo日志內(nèi)容
{"name":"張三","age":10}
{"name":"李四","age":11}
{"name":"李四"}
{"age":11}{"data":[{"label":"123","acc":1,"version":"4.3.1"}]}
{"data":[{"label":"789","acc":1,"version":"4.3.1"},{"label":"78","acc":100,"version":"4.3.1"}]}
{"data":[{"label":"5356","acc":1,"version":"4.3.1"}]}data1.log
data.log
反序列化簡單json字符串
val spark = SparkSession.builder().master("local[2]").appName("FastJsonTest").getOrCreate()
val input1 = "data.log"val jsonRDD1 = spark.sparkContext.textFile(input1)
val dataRDD1 = jsonRDD1.map(json => {
val jsonObject = JSON.parseObject(json)
val name = jsonObject.getOrDefault("name",null)
val age = jsonObject.getOrDefault("age",null)
(name,age)
})
dataRDD1.foreach(println)// 輸出結(jié)果 (李四,null)
(null,11)
(張三,10)
(李四,11)反序列化簡單json字符串組，實(shí)現(xiàn)一行變多行地解析json字符串。這個我也沒找到很好的方法，歡迎讀者指教一下
val input2 = "data1.log"val jsonRDD2 = spark.sparkContext.textFile(input2)
val dataRDD2 = jsonRDD2.map(json => { JSON.parseObject(json).getJSONArray("data").toString
}).map(x => x.substring(1,x.length-1).replace("},{","}---{")) // 去掉字符串中的[]，并替換},{成}---{，目的是用于區(qū)分
.flatMap(x => x.split("---")) // 字符串按----拆分
.map(x => JSON.parseObject(x))
val data2 = dataRDD2.map(jsonObject => {
val version = jsonObject.getOrDefault("version",null)
val label = jsonObject.getOrDefault("label",null)
val acc = jsonObject.getOrDefault("acc",null)
(version,label,acc)
})
data2.foreach(println)// 輸出結(jié)果(4.3.1,5356,1)
(4.3.1,123,1)
(4.3.1,789,1)
(4.3.1,78,100)val dataRDD3 = jsonRDD2.flatMap(json => {
val jsonArray = JSON.parseObject(json).getJSONArray("data") var dataList : List[String] = List() // 創(chuàng)建一個List
for (i <- 0 to jsonArray.size()-1) {
dataList = jsonArray.get(i).toString :: dataList
}
dataList
}).map(x => JSON.parseObject(x))
val data3 = dataRDD3.map(jsonObject => {
val version = jsonObject.getOrDefault("version",null)
val label = jsonObject.getOrDefault("label",null)
val acc = jsonObject.getOrDefault("acc",null)
(version,label,acc)
})
data3.foreach(println)// 輸出結(jié)果(4.3.1,5356,1)
(4.3.1,123,1)
(4.3.1,789,1)
(4.3.1,78,100)方法二：List
方法一：字符串處理
序列化一個簡單java Bean對象
val arr = Seq("tom:10", "bob:14", "hurry:9")
val dataRdd = spark.sparkContext.parallelize(arr)
val dataString = dataRdd.map(x => {
val arr = x.split(":")
val name = arr(0)
val age = arr(1).toInt
val u = new User(name,age)
u
}).map(x => { JSON.toJSONString(x,SerializerFeature.WriteMapNullValue) // 這里需要顯示SerializerFeature中的某一個，否則會報(bào)同時(shí)匹配兩個方法的錯誤})
dataString.foreach(println)// 輸出結(jié)果{"age":10,"name":"tom"}
{"age":14,"name":"bob"}
{"age":9,"name":"hurry"}https://segmentfault.com/a/1190000011212806
https://www.cnblogs.com/cdf-opensource-007/p/7106018.html
https://github.com/alibaba/fastjson
https://blog.csdn.net/universsky2015/article/details/77965563?locationNum=9&fps=1
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