Maven dependency -
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.9.6</version>
</dependency>
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convert java Map to JSON string - using Jackson Api
package com.ankit.json;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import com.fasterxml.jackson.core.JsonGenerationException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;
public class ConvertJavaMapToJson {
public static void main(String[] args) {
try {
ObjectMapper objectMapper = new ObjectMapper();
String jsonInString = "";
List<String> addesss = new ArrayList<>();
addesss.add("Paris");
addesss.add("London");
// Create Map
Map<String, Object> map = new HashMap<String, Object>();
map.put("empId", 11);
map.put("name", "Ankit");
map.put("address", addesss);
System.out.println("map = "+map);
// convert java Map to JSON string
jsonInString = objectMapper.writeValueAsString(map);
System.out.println("\njsonInString = "+jsonInString);
String jsonInStringPretty = objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString(map);
// pretty print the JSON
System.out.println("\njsonInStringPretty = "+jsonInStringPretty);
} catch (JsonGenerationException e) {
e.printStackTrace();
} catch (JsonMappingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
//output
/*
map = {empId=11, address=[Paris, London], name=Ankit}
jsonInString = {"empId":11,"address":["Paris","London"],"name":"Ankit"}
jsonInStringPretty = {
"empId" : 11,
"address" : [ "Paris", "London" ],
"name" : "Ankit"
}
*/
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Employee class
import java.util.List;
public class Employee {
//Fields
private int empId;
private String name;
private List<String> address;
public Employee() {
super();
}
public Employee(int empId, String name, List<String> address) {
super();
this.empId = empId;
this.name = name;
this.address = address;
}
@Override
public String toString() {
return "Employee [empId=" + empId + ", name=" + name + ", address=" + address + "]";
}
//Setter and getters
public int getEmpId() {
return empId;
}
public void setEmpId(int empId) {
this.empId = empId;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public List<String> getAddress() {
return address;
}
public void setAddress(List<String> address) {
this.address = address;
}
}
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Related links >
1. Jackson JSON -
We can use Jackson api for for processing JSON in java.
Jackson JSON examples
2. Java provides API (JSR 353) for Processing JSON (JSR 353).
It provides -
- Object Model API
- Streaming API
Java API for JSON processing examples >