Java多行打印JSONObject

Question

当我从this link运行“将JSON写入文件”代码时，整个JSON对象将打印到文件中的一行。如何打印JSONObject以便多行显示？

这是我得到的输出：

{“ firstName”：“ John”，“ lastName”：“ Smith”，“ address”：{“ streetAddress”：“ 21 2nd Street”，“ city”：“ New York”，“ state”：“ NY “，” postalCode“：10021}，” age“：25，” phoneNumbers“：[{” type“：” home“，” number“：” 212 555-1234“}，{” type“：” fax“， “ number”：“ 212 555-1234”}]}

代码如下所示：

// Java program for write JSON to a file 

import java.io.FileNotFoundException; 
import java.io.PrintWriter; 
import java.util.LinkedHashMap; 
import java.util.Map; 
import org.json.simple.JSONArray; 
import org.json.simple.JSONObject; 

public class JSONWriteExample 
{ 
    public static void main(String[] args) throws FileNotFoundException 
    { 
        // creating JSONObject 
        JSONObject jo = new JSONObject(); 

        // putting data to JSONObject 
        jo.put("firstName", "John"); 
        jo.put("lastName", "Smith"); 
        jo.put("age", 25); 

        // for address data, first create LinkedHashMap 
        Map m = new LinkedHashMap(4); 
        m.put("streetAddress", "21 2nd Street"); 
        m.put("city", "New York"); 
        m.put("state", "NY"); 
        m.put("postalCode", 10021); 

        // putting address to JSONObject 
        jo.put("address", m); 

        // for phone numbers, first create JSONArray 
        JSONArray ja = new JSONArray(); 

        m = new LinkedHashMap(2); 
        m.put("type", "home"); 
        m.put("number", "212 555-1234"); 

        // adding map to list 
        ja.add(m); 

        m = new LinkedHashMap(2); 
        m.put("type", "fax"); 
        m.put("number", "212 555-1234"); 

        // adding map to list 
        ja.add(m); 

        // putting phoneNumbers to JSONObject 
        jo.put("phoneNumbers", ja); 

        // writing JSON to file:"JSONExample.json" in cwd 
        PrintWriter pw = new PrintWriter("JSONExample.json"); 
        pw.write(jo.toJSONString()); 

        pw.flush(); 
        pw.close(); 
    } 
}