使用Java构建json

注：这里要使用到json.jar包

具体的代码如下：

package testJson;

import java.util.HashMap;
import java.util.Map;

import org.json.JSONObject;

import bean.DiaoSi;

public class CreateJson {

	public static void main(String[] args) {
		createJsonByPut();
		createJsonByMap();
		createJsonByBean();
	}

	// 使用put方法构建
	private static void createJsonByPut() {
		JSONObject wangxiaoer = new JSONObject();
		String nullObj = null;
		try {
			wangxiaoer.put("name", "王小二");
			wangxiaoer.put("age", 25.2);
			wangxiaoer.put("birthday", "1990-01-01");
			wangxiaoer.put("school", "蓝翔");
			wangxiaoer.put("major", new String[] {"理发", "挖掘机"});
			wangxiaoer.put("house", nullObj); // 这里不能直接写null
			
			System.out.println(wangxiaoer.toString());
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	
	// 使用map方式构建
	private static void createJsonByMap() {
		Map wangxiaoer = new HashMap();
		Object nullObj = null;
		
		wangxiaoer.put("name", "王小二");
		wangxiaoer.put("age", 25.2);
		wangxiaoer.put("birthday", "1990-01-01");
		wangxiaoer.put("school", "蓝翔");
		wangxiaoer.put("major", new String[] {"理发", "挖掘机"});
		wangxiaoer.put("house", nullObj);
		
		System.out.println(new JSONObject(wangxiaoer).toString());
	}
	
	// 使用Java Bean
	private static void createJsonByBean() {
		DiaoSi wangxiaoer = new DiaoSi();
		
		wangxiaoer.setName("王小二");
		wangxiaoer.setAge(25.2);
		wangxiaoer.setBirthday("1990-01-01");
		wangxiaoer.setSchool("蓝翔");
		wangxiaoer.setMajor(new String[] {"理发", "挖掘机"});
		wangxiaoer.setHouse(null);
		
		System.out.println(new JSONObject(wangxiaoer).toString());
	}
}

第三种方式中使用到的java bean代码如下：

package bean;

public class DiaoSi {
	
	private String name;
	private String school;
	private double age;
	private Object house;
	private String[] major;
	private String birthday;
	
	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 double getAge() {
		return age;
	}
	public void setAge(double age) {
		this.age = age;
	}
	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 getBirthday() {
		return birthday;
	}
	public void setBirthday(String birthday) {
		this.birthday = birthday;
	}
	
}

最后我们看这三种方式所输出的结果：

{"birthday":"1990-01-01","school":"蓝翔","age":25.2,"name":"王小二","major":["理发","挖掘机"]}
{"birthday":"1990-01-01","school":"蓝翔","age":25.2,"name":"王小二","house":null,"major":["理发","挖掘机"]}
{"birthday":"1990-01-01","school":"蓝翔","age":25.2,"name":"王小二","house":null,"major":["理发","挖掘机"]}

可以看到，第一种put方法构建的json直接过滤掉了为null的house项