json篇_json 字符集-优快云博客

本文介绍使用Java创建和操作JSON对象的三种方法：直接new、通过Map集合转换、利用JavaBean对象转换。同时展示了如何使用Gson进行定制化输出及忽略特定字段。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

雷区：1、json的要求字符集必须是Unicode，如果为其他编码格式会产生空、乱码等问题。

josn.org工程包：创建json对象三种方式

//三种创建json对象的方式
public static void main(String[] args) {
	jSONObjectSample();
	createJSONObjectByMap();
	createJSONObjectByBean();
}
//直接new
public static void jSONObjectSample() {
	JSONObject fangao = new JSONObject();
	Object nullObj = null;
	fangao.put("name", "梵高");
	fangao.put("age", 26);
	fangao.put("birthday", "1853-3-30");
	fangao.put("major",new String[] {"牧师","画家"});
	fangao.put("has_girlfriend", false);
	fangao.put("car", nullObj);
	fangao.put("house", nullObj);
	fangao.put("comment", "伟大的画家，悲催的人生");
	System.out.println(fangao.toString());
}
//map集合
public static void createJSONObjectByMap() {
	Map<String, Object> fangao = new HashMap<String, Object>();
	Object nullObj = null;
	fangao.put("name", "梵高");
	fangao.put("age", 26);
	fangao.put("birthday", "1853-3-30");
	fangao.put("major",new String[] {"牧师","画家"});
	fangao.put("has_girlfriend", false);
	fangao.put("car", nullObj);
	fangao.put("house", nullObj);
	fangao.put("comment", "伟大的画家，悲催的人生");
	System.out.println(new JSONObject(fangao).toString());
}
//javabean
public static void createJSONObjectByBean() {
	Person fangao = new Person();
	fangao.setName("梵高");
	fangao.setAge(26);
	fangao.setBirthday("1853-3-30");
	fangao.setMajor(new String[] {"牧师","画家"});
	fangao.setHas_girlfriend(false);
	fangao.setCar(null);
	fangao.setHouse(null);
	fangao.setComment("伟大的画家，悲催的人生");
	System.out.println(new JSONObject(fangao).toString());
}

读取文件中的json

import java.io.File;
import java.io.IOException;
import org.apache.commons.io.FileUtils;
import org.json.JSONObject;

public class ReadJSONSample {
	public static void main(String[] args) throws IOException {
		File file = new File(ReadJSONSample.class.getResource("/fangao.json").getFile());
		String content = FileUtils.readFileToString(file);
		JSONObject jsonObject = new JSONObject(content);
		System.out.println(jsonObject.getString("name"));
	}
}

{
  "birthday": "1853-3-30",
  "major": [
    "牧师",
    "画家"
  ],
  "name": "梵高",
  "has_girlfriend": false,
  "comment": "伟大的画家，悲催的人生",
  "age": 26
}

gson工程包

public class Person {	
	private String name;
	private double age;
	private String birthday;
	private String[] major;
	private boolean has_girlfriend;
	private Object car;
	private Object house;
	private String comment;
	private transient String ignore;   //gson生成json对象时忽略这个字段
}

	
public static void createJSONObjectByGson() {
	Person fangao = new Person();
	fangao.setName("梵高");
	fangao.setAge(26);
	fangao.setBirthday("1853-3-30");
	fangao.setMajor(new String[] { "牧师", "画家" });
	fangao.setHas_girlfriend(false);
	fangao.setCar(null);
	fangao.setHouse(null);
	fangao.setComment("伟大的画家，悲催的人生");
	fangao.setIgnore("看不到我");
	//使用GsonBuilder可以在生成json对象之前做一些定制设置
	GsonBuilder gsonBuilder = new GsonBuilder();
	gsonBuilder.setPrettyPrinting();
	gsonBuilder.setFieldNamingStrategy(new FieldNamingStrategy() {
		public String translateName(Field f) {
			if (f.getName().equals("name")) {
				return "NAME";
			}
			return f.getName();
		}
	});
	Gson gson = gsonBuilder.create();
	System.out.println(gson.toJson(fangao));
}

依赖的jar包

<!-- https://mvnrepository.com/artifact/org.json/json -->
<dependency>
	<groupId>org.json</groupId>
	<artifactId>json</artifactId>
	<version>20160810</version>
</dependency>
<!-- https://mvnrepository.com/artifact/commons-io/commons-io -->
<dependency>
	<groupId>commons-io</groupId>
	<artifactId>commons-io</artifactId>
	<version>2.4</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.google.code.gson/gson -->
<dependency>
    <groupId>com.google.code.gson</groupId>
    <artifactId>gson</artifactId>
    <version>2.8.0</version>
</dependency>

附件资料：