Java：JSON與Map相互轉換

需要jar包：jackson-core-2.6.0.jar，jackson-databind-2.6.0.jar，jackson-annotations-2.6.0.jar

1. JSON String to Map

package com.inspur.trc.util;

import java.util.HashMap;

import java.util.Map;

import com.fasterxml.jackson.core.type.TypeReference;

import com.fasterxml.jackson.databind.ObjectMapper;

public class Json2Map {

public static void main(String[] args) {

String json = "{\"name\":\"zitong\", \"age\":\"26\"}";

Map map = new HashMap();

ObjectMapper mapper = new ObjectMapper();

try{

map = mapper.readValue(json, new TypeReference>(){});

System.out.println(map);

}catch(Exception e){

e.printStackTrace();

}

}

}

運行結果：

{age=26, name=zitong}

2. Map to JSON String

package com.inspur.trc.util;

import java.util.HashMap;

import java.util.Map;

import com.fasterxml.jackson.databind.ObjectMapper;

public class Map2Json {

public static void main(String[] args){

try{

ObjectMapper mapper = new ObjectMapper();

String json = "";

Map map = new HashMap();

map.put("name", "zitong");

map.put("age", "26");

json = mapper.writeValueAsString(map);

System.out.println(json);

}catch(Exception e){

e.printStackTrace();

}

}

}

運行結果：

{"age":"26","name":"zitong"}

3. Map to JSON File

package com.inspur.trc.util;

import java.io.File;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import com.fasterxml.jackson.databind.ObjectMapper;

public class Map2JsonFile {

public static void main(String[] args) {

ObjectMapper mapper = new ObjectMapper();

Map map = new HashMap();

map.put("name", "zitong");

map.put("age", 29);

List list = new ArrayList();

list.add("music");

list.add("football");

map.put("hobby", list);

try {

mapper.writeValue(new File("F:/user.json"), map);

} catch (Exception e) {

e.printStackTrace();

}

}

}

運行結果：F:/user.json

{"age":29,"name":"zitong","hobby":["music","football"]}

4. JSON File To Map

package com.inspur.trc.util;

import java.io.File;

import java.util.List;

import java.util.Map;

import com.fasterxml.jackson.core.type.TypeReference;

import com.fasterxml.jackson.databind.ObjectMapper;

public class JsonFile2Map {

public static void main(String[] args) {

try{

ObjectMapper mapper = new ObjectMapper();

Map map = mapper.readValue(new File("F:/user.json"),new TypeReference>(){});

System.out.println("name: " + map.get("name"));

System.out.println("age: " + map.get("age"));

@SuppressWarnings("unchecked")

List list = (List)map.get("hobby");

System.out.print("hobby: ");

for(String str : list){

System.out.print(str+ " ");

}

}catch(Exception e){

e.printStackTrace();

}

}

}

運行結果：

name: zitong

age: 29

hobby: music football

總結

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