how to parse below Json file in java , which has no key

Question

{
 "type": "telemetry",
 "timestamp": 1234,
 "device": 5678,
 "value": { 
   [
     {"battery_level": 87},
     {"var2": 2},
     {"var3": 3} 
   ] 
  }
}

I want to pasre this json file in java code using jsonobject and jsonarray Here, I'm stuck up at values keyword inside has no key to array.

This is not valid JSON. Contact its provider and explain the issue. — Pshemo, Sep 24 '19 at 12:10

score 1 · Answer 1 · answered Sep 24 '19 at 12:46

Your valid JSON would be -

{
 "type": "telemetry",
 "timestamp": 1234,
 "device": 5678,
 "value": 
   [
     {"battery_level": 87},
     {"var2": 2},
     {"var3": 3} 
   ] 

}

You can then use following JAVA POJO objects to parse your json into the java object -

import java.util.List;
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonPropertyOrder;

@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonPropertyOrder({
"type",
"timestamp",
"device",
"value"
})
public class Example {

@JsonProperty("type")
private String type;
@JsonProperty("timestamp")
private Integer timestamp;
@JsonProperty("device")
private Integer device;
@JsonProperty("value")
private List<Value> value = null;

@JsonProperty("type")
public String getType() {
return type;
}

@JsonProperty("type")
public void setType(String type) {
this.type = type;
}

@JsonProperty("timestamp")
public Integer getTimestamp() {
return timestamp;
}

@JsonProperty("timestamp")
public void setTimestamp(Integer timestamp) {
this.timestamp = timestamp;
}

@JsonProperty("device")
public Integer getDevice() {
return device;
}

@JsonProperty("device")
public void setDevice(Integer device) {
this.device = device;
}

@JsonProperty("value")
public List<Value> getValue() {
return value;
}

@JsonProperty("value")
public void setValue(List<Value> value) {
this.value = value;
}

}
-----------------------------------com.example.Value.java-----------------------------------

package com.example;

import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonPropertyOrder;

@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonPropertyOrder({
"battery_level",
"var2",
"var3"
})
public class Value {

@JsonProperty("battery_level")
private Integer batteryLevel;
@JsonProperty("var2")
private Integer var2;
@JsonProperty("var3")
private Integer var3;

@JsonProperty("battery_level")
public Integer getBatteryLevel() {
return batteryLevel;
}

@JsonProperty("battery_level")
public void setBatteryLevel(Integer batteryLevel) {
this.batteryLevel = batteryLevel;
}

@JsonProperty("var2")
public Integer getVar2() {
return var2;
}

@JsonProperty("var2")
public void setVar2(Integer var2) {
this.var2 = var2;
}

@JsonProperty("var3")
public Integer getVar3() {
return var3;
}

@JsonProperty("var3")
public void setVar3(Integer var3) {
this.var3 = var3;
}

}

After your Java objects and JSON is in place use jackson to do the mapping -

ObjectMapper mapper = new ObjectMapper();
String jsonInString = "{'name' : 'mkyong'}";

//JSON from file to Object
User user = mapper.readValue(new File("c:\\user.json"), Example.class);

how to parse below Json file in java , which has no key

1 Answers1