我有以下 JSON 文本。如何解析它以获得pageName
, pagePic
, post_id
等的值?
{
"pageInfo": {
"pageName": "abc",
"pagePic": "http://example.com/content.jpg"
},
"posts": [
{
"post_id": "123456789012_123456789012",
"actor_id": "1234567890",
"picOfPersonWhoPosted": "http://example.com/photo.jpg",
"nameOfPersonWhoPosted": "Jane Doe",
"message": "Sounds cool. Can't wait to see it!",
"likesCount": "2",
"comments": [],
"timeOfPost": "1234567890"
}
]
}
import org.json.*;
JSONObject obj = new JSONObject(" .... ");
String pageName = obj.getJSONObject("pageInfo").getString("pageName");
JSONArray arr = obj.getJSONArray("posts");
for (int i = 0; i < arr.length(); i++)
{
String post_id = arr.getJSONObject(i).getString("post_id");
......
}
private class Person {
public String name;
public Person(String name) {
this.name = name;
}
}
Gson g = new Gson();
Person person = g.fromJson("{\"name\": \"John\"}", Person.class);
System.out.println(person.name); //John
System.out.println(g.toJson(person)); // {"name":"John"}
JsonObject jsonObject = new JsonParser().parse("{\"name\": \"John\"}").getAsJsonObject();
System.out.println(jsonObject.get("name").getAsString()); //John
JSONObject obj = new JSONObject("{\"name\": \"John\"}");
System.out.println(obj.getString("name")); //John
ObjectMapper mapper = new ObjectMapper();
Person user = mapper.readValue("{\"name\": \"John\"}", Person.class);
System.out.println(user.name); //John
如果要从 JSON 创建 Java 对象,反之亦然,请使用 GSON 或 JACKSON 第三方 jar 等。
//from object to JSON
Gson gson = new Gson();
gson.toJson(yourObject);
// from JSON to object
yourObject o = gson.fromJson(JSONString,yourObject.class);
但是,如果只是想解析 JSON 字符串并获取一些值,(或从头开始创建 JSON 字符串以通过电线发送),只需使用包含 JsonReader,JsonArray,JsonObject 等的 JaveEE jar。您可能要下载该实现规格,例如 javax.json。使用这两个 jar,我可以解析 json 并使用这些值。
这些 API 实际上遵循 XML 的 DOM / SAX 解析模型。
Response response = request.get(); // REST call
JsonReader jsonReader = Json.createReader(new StringReader(response.readEntity(String.class)));
JsonArray jsonArray = jsonReader.readArray();
ListIterator l = jsonArray.listIterator();
while ( l.hasNext() ) {
JsonObject j = (JsonObject)l.next();
JsonObject ciAttr = j.getJsonObject("ciAttributes");
JsonParserFactory factory=JsonParserFactory.getInstance();
JSONParser parser=factory.newJsonParser();
Map jsonMap=parser.parseJson(jsonString);
com.fasterxml.jackson.databind.ObjectMapper
package com.levo.jsonex.model;
public class Page {
private PageInfo pageInfo;
private Post[] posts;
public PageInfo getPageInfo() {
return pageInfo;
}
public void setPageInfo(PageInfo pageInfo) {
this.pageInfo = pageInfo;
}
public Post[] getPosts() {
return posts;
}
public void setPosts(Post[] posts) {
this.posts = posts;
}
}
package com.levo.jsonex.model;
public class PageInfo {
private String pageName;
private String pagePic;
public String getPageName() {
return pageName;
}
public void setPageName(String pageName) {
this.pageName = pageName;
}
public String getPagePic() {
return pagePic;
}
public void setPagePic(String pagePic) {
this.pagePic = pagePic;
}
}
package com.levo.jsonex.model;
public class Post {
private String post_id;
private String actor_id;
private String picOfPersonWhoPosted;
private String nameOfPersonWhoPosted;
private String message;
private int likesCount;
private String[] comments;
private int timeOfPost;
public String getPost_id() {
return post_id;
}
public void setPost_id(String post_id) {
this.post_id = post_id;
}
public String getActor_id() {
return actor_id;
}
public void setActor_id(String actor_id) {
this.actor_id = actor_id;
}
public String getPicOfPersonWhoPosted() {
return picOfPersonWhoPosted;
}
public void setPicOfPersonWhoPosted(String picOfPersonWhoPosted) {
this.picOfPersonWhoPosted = picOfPersonWhoPosted;
}
public String getNameOfPersonWhoPosted() {
return nameOfPersonWhoPosted;
}
public void setNameOfPersonWhoPosted(String nameOfPersonWhoPosted) {
this.nameOfPersonWhoPosted = nameOfPersonWhoPosted;
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
public int getLikesCount() {
return likesCount;
}
public void setLikesCount(int likesCount) {
this.likesCount = likesCount;
}
public String[] getComments() {
return comments;
}
public void setComments(String[] comments) {
this.comments = comments;
}
public int getTimeOfPost() {
return timeOfPost;
}
public void setTimeOfPost(int timeOfPost) {
this.timeOfPost = timeOfPost;
}
}
{
"pageInfo": {
"pageName": "abc",
"pagePic": "http://example.com/content.jpg"
},
"posts": [
{
"post_id": "123456789012_123456789012",
"actor_id": "1234567890",
"picOfPersonWhoPosted": "http://example.com/photo.jpg",
"nameOfPersonWhoPosted": "Jane Doe",
"message": "Sounds cool. Can't wait to see it!",
"likesCount": "2",
"comments": [],
"timeOfPost": "1234567890"
}
]
}
package com.levo.jsonex;
import java.io.File;
import java.io.IOException;
import java.util.Arrays;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.levo.jsonex.model.Page;
import com.levo.jsonex.model.PageInfo;
import com.levo.jsonex.model.Post;
public class JSONDemo {
public static void main(String[] args) {
ObjectMapper objectMapper = new ObjectMapper();
try {
Page page = objectMapper.readValue(new File("sampleJSONFile.json"), Page.class);
printParsedObject(page);
} catch (IOException e) {
e.printStackTrace();
}
}
private static void printParsedObject(Page page) {
printPageInfo(page.getPageInfo());
System.out.println();
printPosts(page.getPosts());
}
private static void printPageInfo(PageInfo pageInfo) {
System.out.println("Page Info;");
System.out.println("**********");
System.out.println("\tPage Name : " + pageInfo.getPageName());
System.out.println("\tPage Pic : " + pageInfo.getPagePic());
}
private static void printPosts(Post[] posts) {
System.out.println("Page Posts;");
System.out.println("**********");
for(Post post : posts) {
printPost(post);
}
}
private static void printPost(Post post) {
System.out.println("\tPost Id : " + post.getPost_id());
System.out.println("\tActor Id : " + post.getActor_id());
System.out.println("\tPic Of Person Who Posted : " + post.getPicOfPersonWhoPosted());
System.out.println("\tName Of Person Who Posted : " + post.getNameOfPersonWhoPosted());
System.out.println("\tMessage : " + post.getMessage());
System.out.println("\tLikes Count : " + post.getLikesCount());
System.out.println("\tComments : " + Arrays.toString(post.getComments()));
System.out.println("\tTime Of Post : " + post.getTimeOfPost());
}
}
Page Info;
****(*****
Page Name : abc
Page Pic : http://example.com/content.jpg
Page Posts;
**********
Post Id : 123456789012_123456789012
Actor Id : 1234567890
Pic Of Person Who Posted : http://example.com/photo.jpg
Name Of Person Who Posted : Jane Doe
Message : Sounds cool. Can't wait to see it!
Likes Count : 2
Comments : []
Time Of Post : 1234567890
<dependency>
<groupId>com.jayway.jsonpath</groupId>
<artifactId>json-path</artifactId>
<version>${version}</version>
</dependency>
String pageName = JsonPath.read(yourJsonString, "$.pageInfo.pageName");
String pagePic = JsonPath.read(yourJsonString, "$.pageInfo.pagePic");
String post_id = JsonPath.read(yourJsonString, "$.pagePosts[0].post_id");
{
"pageInfo": {
"pageName": "abc",
"pagePic": "http://example.com/content.jpg"
}
"posts": [
{
"post_id": "123456789012_123456789012",
"actor_id": "1234567890",
"picOfPersonWhoPosted": "http://example.com/photo.jpg",
"nameOfPersonWhoPosted": "Jane Doe",
"message": "Sounds cool. Can't wait to see it!",
"likesCount": "2",
"comments": [],
"timeOfPost": "1234567890"
}
]
}
class MyModel {
private PageInfo pageInfo;
private ArrayList<Post> posts = new ArrayList<>();
}
class PageInfo {
private String pageName;
private String pagePic;
}
class Post {
private String post_id;
@SerializedName("actor_id") // <- example SerializedName
private String actorId;
private String picOfPersonWhoPosted;
private String nameOfPersonWhoPosted;
private String message;
private String likesCount;
private ArrayList<String> comments;
private String timeOfPost;
}
MyModel model = gson.fromJson(jsonString, MyModel.class);
{
"order": 4711,
"items": [
{
"name": "NE555 Timer IC",
"cat-id": "645723",
"quantity": 10,
},
{
"name": "LM358N OpAmp IC",
"cat-id": "764525",
"quantity": 2
}
]
}
JsonObject object = Json.parse(input).asObject();
int orders = object.get("order").asInt();
JsonArray items = object.get("items").asArray();
JsonObject user = Json.object().add("name", "Sakib").add("age", 23);
<dependency>
<groupId>com.eclipsesource.minimal-json</groupId>
<artifactId>minimal-json</artifactId>
<version>0.9.4</version>
</dependency>
我认为最佳做法应该是通过仍在进行中的官方Java JSON API 。
javax.json.JsonReader jr =
javax.json.Json.createReader(new StringReader(jsonText));
javax.json.JsonObject jo = jr.readObject();
//Read the page info.
javax.json.JsonObject pageInfo = jo.getJsonObject("pageInfo");
System.out.println(pageInfo.getString("pageName"));
//Read the posts.
javax.json.JsonArray posts = jo.getJsonArray("posts");
//Read the first post.
javax.json.JsonObject post = posts.getJsonObject(0);
//Read the post_id field.
String postId = post.getString("post_id");