How to Set Json Request Body using ObjectMapper, JsonNode and ObjectNode一文中有介绍ObjectMapper的使用，它可以解析（读）json文件，也可以创建（写）json格式的结构，还可以用来修改json文件，这对API测试非常有用。本文中介绍另外一种处理json的类JSONObject，本人也是经常会混淆ObjectMapper，JSONObject和JSONPath，因为这几个类都处理JSON，在API Testing经常应用到。
Java提供很多JSON 包，来帮助我们处理JSON格式数据。经常用到的两个包是org.json and org.json.simple。
什么是JSONObject
在Java中，JSONObject是name-value键值对的集合，是无序的，不可更改的。
JsonObject class represents an
immutableJSON object value (anunorderedcollection of zero or more name/value pairs). It also providesunmodifiablemap view to the JSON object name/value mappings.
例如在下述例子中，：first name, city, age是names， kelly，Shanghai，18分别是values
{
"first name": "Kelly",
"city": "Shanghai",
"age": "18"
},
Java JSONObject class
Java中的JSONObject类定义在org.json包，JSONObject值可以是Boolean, String, Number, JSONObject, JSONArray, JSONNumber, JSONString, 这些SONObject values 可以通过相应的方法获取，具体方法可以参考官网。
Note: 在使用get()方法时，如果value找不到将会抛出异常，而opt()方法不会抛异常而是返回默认值，value可以为null。
从Json中获取Values
org.json例子
POM添加包依赖：
<dependency>
<groupId>org.json</groupId>
<artifactId>json</artifactId>
<version>20180813</version>
</dependency>
import org.json.*;
public class GetValueFromJsonExample
{
public static void main(String[] args) throws JSONException
{
//constructor of the JSONObject class
JSONObject obj = new JSONObject(
"{" +
"Employee ID: 092789," +
"Employee Name: Helen Mirren," +
"Age: 27, " +
"Designation: Assistant Manager," +
"City: Florida," +
"Salary: 67000.00, " +
"Experience: 26 " +
"}"
);
//getting values form the JSONObject
System.out.println("Employee ID: "+obj.getInt("Employee ID"));
System.out.println("Employee Name: "+obj.getString("Employee Name"));
System.out.println("Age: "+obj.getInt("Age"));
System.out.println("Designation: "+obj.getString("Designation"));
System.out.println("City: "+obj.getString("City"));
System.out.println("Salary: "+obj.getDouble("Salary"));
System.out.println("Experience: "+obj.getInt("Experience") +" Months");
}
}
json-simple例子
JSONExample.json内容如下 :
{
"lastName":"Smith",
"address":{
"streetAddress":"21 2nd Street",
"city":"New York",
"state":"NY",
"postalCode":10021
},
"age":25,
"phoneNumbers":[
{
"type":"home", "number":"212 555-1234"
},
{
"type":"fax", "number":"212 555-1234"
}
],
"firstName":"John"
}
// Java program to read JSON from a file
import java.io.FileReader;
import java.util.Iterator;
import java.util.Map;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.*;
public class JSONReadExample
{
public static void main(String[] args) throws Exception
{
// parsing file "JSONExample.json"
Object obj = new JSONParser().parse(new FileReader("JSONExample.json"));
// typecasting obj to JSONObject
JSONObject jo = (JSONObject) obj;
// getting firstName and lastName
String firstName = (String) jo.get("firstName");
String lastName = (String) jo.get("lastName");
System.out.println(firstName);
System.out.println(lastName);
// getting age
long age = (long) jo.get("age");
System.out.println(age);
// getting address
Map address = ((Map)jo.get("address"));
// iterating address Map
Iterator<Map.Entry> itr1 = address.entrySet().iterator();
while (itr1.hasNext()) {
Map.Entry pair = itr1.next();
System.out.println(pair.getKey() + " : " + pair.getValue());
}
// getting phoneNumbers
JSONArray ja = (JSONArray) jo.get("phoneNumbers");
// iterating phoneNumbers
Iterator itr2 = ja.iterator();
while (itr2.hasNext())
{
itr1 = ((Map) itr2.next()).entrySet().iterator();
while (itr1.hasNext()) {
Map.Entry pair = itr1.next();
System.out.println(pair.getKey() + " : " + pair.getValue());
}
}
}
}
创建Json
org.json 例子
例如创建一个ES json 查询：查询sentiment为NEUTRAL且expert_id为5fdb9d048ccd9819e3b3d70b记录。
{
"query": {
"bool": {
"must": [
{
"match": {
"sentiment": "NEUTRAL"
}
},
{
"match": {
"expert_id": "5fdb9d048ccd9819e3b3d70b"
}
}
]
}
}
}
import org.json.*;
public class Test {
public static void main(String[] args)
{
JSONObject sentimentJsonNodes = new JSONObject();
JSONObject sentimentNode = new JSONObject();
sentimentNode.put("sentiment", sentiment);
JSONObject matchNodeOne = new JSONObject();
matchNodeOne.put("match", sentimentNode);
JSONObject expertIDNode = new JSONObject();
expertIDNode.put("expert_id", expertID);
JSONObject matchNodeTwo = new JSONObject();
matchNodeTwo.put("match", expertIDNode);
JSONArray matchList = new JSONArray();
matchList.put(matchNodeOne);
matchList.put(matchNodeTwo);
JSONObject mustNode = new JSONObject();
mustNode.put("must", matchList);
JSONObject boolNode = new JSONObject();
boolNode.put("bool", mustNode);
sentimentJsonNodes.put("query", boolNode);
System.out.print(sentimentJsonNodes.toString());
}
}
json.simple 例子
build下面这个json
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{
"firstName": "John",
"lastName": "Smith",
"age": 25,
"address": {
"streetAddress": "21 2nd Street",
"city": "New York",
"state": "NY",
"postalCode": 10021
},
"phoneNumbers": [
{
"type": "home",
"number": "212 555-1234"
},
{
"type": "fax",
"number": "646 555-4567"
}
]
}
// Java program for write JSON to a file
import java.io.FileNotFoundException;
import java.io.PrintWriter;
import java.util.LinkedHashMap;
import java.util.Map;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
public class JSONWriteExample
{
public static void main(String[] args) throws FileNotFoundException
{
// creating JSONObject
JSONObject jo = new JSONObject();
// putting data to JSONObject
jo.put("firstName", "John");
jo.put("lastName", "Smith");
jo.put("age", 25);
// for address data, first create LinkedHashMap
Map m = new LinkedHashMap(4);
m.put("streetAddress", "21 2nd Street");
m.put("city", "New York");
m.put("state", "NY");
m.put("postalCode", 10021);
// putting address to JSONObject
jo.put("address", m);
// for phone numbers, first create JSONArray
JSONArray ja = new JSONArray();
m = new LinkedHashMap(2);
m.put("type", "home");
m.put("number", "212 555-1234");
// adding map to list
ja.add(m);
m = new LinkedHashMap(2);
m.put("type", "fax");
m.put("number", "212 555-1234");
// adding map to list
ja.add(m);
// putting phoneNumbers to JSONObject
jo.put("phoneNumbers", ja);
// writing JSON to file:"JSONExample.json" in cwd
PrintWriter pw = new PrintWriter("JSONExample.json");
pw.write(jo.toJSONString());
pw.flush();
pw.close();
}
}
总结：
JSONObject可以读Json获取信息，也可以写入一个Json文件，但是不能Edit一个已经存在的Json，因为JSONObject是immutable不可能更改的。
参考：
How to parse JSON in Java
Interface JsonObject
How to Get Value from JSON Object in Java Example