GSON生成与解析JSON数据

曾经终败给现在 2022-06-05 05:53 317阅读 0赞

代码:

\#JSON对应的实体类

package com.east.entity;
    
    import java.io.Serializable;
    import java.util.Arrays;
    
    import com.google.gson.annotations.SerializedName;
    
    public class User implements Serializable {
    	@SerializedName("Name")     //在转换为json格式后变为大写的Name
        private String name;
        private String school;
        private boolean has_girlfriend;
        private double age;
        private Object car;
        private Object house;
        private String[] major;
        private String comment;
        private String birthday;
        private transient String ignore;      //生成json时忽略该字段
        
    	public String getIgnore() {
    		return ignore;
    	}
    	public void setIgnore(String ignore) {
    		this.ignore = ignore;
    	}
    	public String getName() {
    		return name;
    	}
    	public void setName(String name) {
    		this.name = name;
    	}
    	public String getSchool() {
    		return school;
    	}
    	public void setSchool(String school) {
    		this.school = school;
    	}
    	public boolean isHas_girlfriend() {
    		return has_girlfriend;
    	}
    	public void setHas_girlfriend(boolean has_girlfriend) {
    		this.has_girlfriend = has_girlfriend;
    	}
    	public double getAge() {
    		return age;
    	}
    	public void setAge(double age) {
    		this.age = age;
    	}
    	public Object getCar() {
    		return car;
    	}
    	public void setCar(Object car) {
    		this.car = car;
    	}
    	public Object getHouse() {
    		return house;
    	}
    	public void setHouse(Object house) {
    		this.house = house;
    	}
    	public String[] getMajor() {
    		return major;
    	}
    	public void setMajor(String[] major) {
    		this.major = major;
    	}
    	public String getComment() {
    		return comment;
    	}
    	public void setComment(String comment) {
    		this.comment = comment;
    	}
    	public String getBirthday() {
    		return birthday;
    	}
    	public void setBirthday(String birthday) {
    		this.birthday = birthday;
    	}
    	@Override
    	public String toString() {
    		return "User [name=" + name + ", school=" + school + ", has_girlfriend=" + has_girlfriend + ", age=" + age
    				+ ", car=" + car + ", house=" + house + ", major=" + Arrays.toString(major) + ", comment=" + comment
    				+ ", birthday=" + birthday + "]";
    	}
        
    }

\#要读取的JSON文件(user.json)

{
      "Name": "杨旭",
      "school": "山东蓝翔",
      "has_girlfriend": false,
      "age": 22.5,
      "major": [
        "理发",
        "挖掘机"
      ],
      "comment": "这是一个注释!",
      "birthday": "1995-08-18"
    }

\#三种方式生成JSON数据

package com.east.util.jsonObject;
    
    import java.lang.reflect.Field;
    import java.util.HashMap;
    import java.util.Map;
    
    import com.east.entity.User;
    import com.google.gson.FieldNamingStrategy;
    import com.google.gson.Gson;
    import com.google.gson.GsonBuilder;
    
    import net.sf.json.JSONObject;
    
    public class JsonObjectUtil {
    	/*
    	 * 使用JsonObject生成json数据
    	 */
    	public String JsonObject() {
    		JSONObject json = new JSONObject();
    		Object nullobj = null;
    		try {
    			json.put("name", "杨旭");
    			json.put("age", 22.5);
    			json.put("birthday", "1995-08-18");
    			json.put("school", "山东蓝翔");
    			json.put("major", new String[] { "理发", "挖掘机" });
    			json.put("has_girlfriend", false);
    			json.put("car", nullobj);
    			json.put("house", nullobj);
    			json.put("comment", "这是一个注释!");
    		} catch (Exception e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    		String JSON = json.toString(); // 将json格式转为字符串
    		return JSON;
    	}
    
    	/*
    	 * 通过HashMap构建JSON数据
    	 */
    	public String CreateJsonByMap() {
    		Map<String, Object> json = new HashMap<String, Object>();
    		Object nullobj = null;
    		json.put("name", "杨旭");
    		json.put("age", 22.5);
    		json.put("birthday", "1995-08-18");
    		json.put("school", "山东蓝翔");
    		json.put("major", new String[] { "理发", "挖掘机" });
    		json.put("has_girlfriend", false);
    		json.put("car", nullobj);
    		json.put("house", nullobj);
    		json.put("comment", "这是一个注释!");
    		
    		return (new JSONObject(json).toString());
    	}
    	
    	/*
    	 * 通过JavaBean构建JSON
    	 */
    	public String CreateJsonByBean() {
    		User user = new User();
    		user.setName("杨旭");
    		user.setAge(22.5);
    		user.setBirthday("1995-08-18");
    		user.setSchool("山东蓝翔");
    		user.setMajor(new String []{"理发", "挖掘机"});
    		user.setHas_girlfriend(false);
    		user.setCar(null);
    		user.setHouse(null);
    		user.setComment("这是一个注释!");
    		user.setIgnore("不能看见我!");
    		
    //		Gson gson = new Gson();
    		//个性化生成json
    		GsonBuilder builder = new GsonBuilder();
    		builder.setPrettyPrinting();
    		//生成json过程中做处理
    		builder.setFieldNamingStrategy(new FieldNamingStrategy(){
    			@Override
    			public String translateName(Field f) {
    				// TODO Auto-generated method stub
    				if(f.getName().equals("name")){
    					return "Name";
    				}
    				return f.getName();
    			}
    			
    		});
    		//个性化创建json,格式化
    		Gson gson = builder.create();
    		String json = gson.toJson(user);
    		return (json);
    	}
    }

\#读取JSON文件(user.json),解析成实体类(User)

package com.east.read;
    
    import java.io.File;
    import java.io.IOException;
    import java.net.URLEncoder;
    
    import org.apache.commons.io.FileUtils;
    
    import com.east.entity.User;
    import com.google.gson.Gson;
    
    public class GsonRead {
    	public User getJson() throws IOException{
    	  File file = new File(GsonRead.class.getResource("/user.json").getFile());
    	  String content = FileUtils.readFileToString(file);
    //	  content = URLEncoder.encode(content, "UTF-8");         //避免文件编码错误
    	  Gson gson = new Gson();
    	  User user = gson.fromJson(content, User.class);
    	  return user;
    	}
    }

\#测试类(Test.java)

package com.east.test;
    
    import java.io.IOException;
    import java.util.HashMap;
    import java.util.Map;
    
    import com.east.entity.User;
    import com.east.read.GsonRead;
    import com.east.util.jsonObject.JsonObjectUtil;
    
    import net.sf.json.JSONObject;
    
    public class Test {
    
    	public static void main(String[] args) throws IOException {
    		JsonObjectUtil util = new JsonObjectUtil();
    		/*
    		 * 使用JsonObject解析成json数据
    		 */
    		String json = util.JsonObject();
    		System.out.println(json);
    		
    		/*
    		 * 通过HashMap构建JSON
    		 */
    		String json = util.CreateJsonByMap();
    		System.out.println(json);
    		
    		/*
    		 * 通过gson创建json
    		 */
    		String json = util.CreateJsonByBean();
    		System.out.println(json);
    		
    		/*
    		 * GSON解析文件
    		 */
    		GsonRead read = new GsonRead();
    		User user = read.getJson();
    		System.out.println(user);
    	}
    
    }