Java:JSON与Map相互转换
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<String, String> map = new HashMap<String, String>();
- ObjectMapper mapper = new ObjectMapper();
-
- try{
- map = mapper.readValue(json, new TypeReference<HashMap<String,String>>(){});
- System.out.println(map);
- }catch(Exception e){
- e.printStackTrace();
- }
- }
- }
运行结果:
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<String, String> map = new HashMap<String,String>();
- map.put("name", "zitong");
- map.put("age", "26");
-
- json = mapper.writeValueAsString(map);
-
- System.out.println(json);
- }catch(Exception e){
- e.printStackTrace();
- }
- }
- }
运行结果:
- {"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<String, Object> map = new HashMap<String, Object>();
- map.put("name", "zitong");
- map.put("age", 29);
-
- List<Object> list = new ArrayList<Object>();
- list.add("music");
- list.add("football");
-
- map.put("hobby", list);
-
- try {
- mapper.writeValue(new File("F:/user.json"), map);
- } catch (Exception e) {
- e.printStackTrace();
- }
-
- }
- }
运行结果: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<String, Object> map = mapper.readValue(new File("F:/user.json"),new TypeReference<Map<String, Object>>(){});
-
- System.out.println("name: " + map.get("name"));
- System.out.println("age: " + map.get("age"));
-
- @SuppressWarnings("unchecked")
- List<String> list = (List<String>)map.get("hobby");
- System.out.print("hobby: ");
- for(String str : list){
- System.out.print(str+ " ");
- }
-
- }catch(Exception e){
- e.printStackTrace();
- }
- }
- }
运行结果:
- name: zitong
- age: 29
- hobby: music football