记录心得-FastJson分层解析demo示例

记录一下，平时用到，可速查！
关键：

//        startArray(); 开始解析数组
//        endArray(); 结束解析数组
//        startObject(); 开始解析键值对
//        endObject(); 结束解析键值对
需要用到的jar包:http://repo1.maven.org/maven2/com/alibaba/fastjson/1.2.6/fastjson-1.2.6.jar

demoJson:{
  "array": [
    1,
    2,
    3
  ],
  "arraylist": [
    {
      "a": "b",
      "c": "d",
      "e": "f"
    },
    {
      "a": "b",
      "c": "d",
      "e": "f"
    },
    {
      "a": "b",
      "c": "d",
      "e": "f"
    }
  ],
  "object": {
    "a": "b",
    "c": "d",
    "e": "f"
  },
  "string": "Hello World"
}

/**
 * Copyright (C), 2015-2019, XXX有限公司
 * FileName: FastJsonTest
 * Author:   zhang.tong2
 * Date:     2019/2/26 9:03
 * Description:
 * History:
 * <author>          <time>          <version>          <desc>
 * 作者姓名           修改时间           版本号              描述
 */
package com.tong.appoint.web;

import com.alibaba.fastjson.JSONReader;

import java.io.StringReader;

/**
 * 〈一句话功能简述〉<br> 
 * 〈〉
 *
 * @author zhang.tong2
 * @create 2019/2/26
 * @since 1.0.0
 */
public class FastJsonTest {
    /**
     * FastJson逐行解析json
     * @author drlyee
     * @date 2015-02-10
     */

    public static void main(String[] args){
        ReadWithFastJson();
    }

    public static void ReadWithFastJson()
    {


        String jsonString = "{"array":[1,2,3],"arraylist":[{"a":"b","c":"d","e":"f"},{"a":"b","c":"d","e":"f"},{"a":"b","c":"d","e":"f"}],"object":{"a":"b","c":"d","e":"f"},"string":"HelloWorld"}";

        // 如果json数据以形式保存在文件中，用FileReader进行流读取！！
        // path为json数据文件路径！！
        // JSONReader reader = new JSONReader(new FileReader(path));

        // 为了直观，方便运行，就用StringReader做示例！
//        startArray(); 开始解析数组
//        endArray(); 结束解析数组
//        startObject(); 开始解析键值对
//        endObject(); 结束解析键值对
        JSONReader reader = new JSONReader(new StringReader(jsonString));
        reader.startObject();
        System.out.print("start fastjson");
        while (reader.hasNext())
        {
            String key = reader.readString();
            System.out.print("key " + key);
            if (key.equals("array"))
            {
                reader.startArray();
                System.out.print("start " + key);
                while (reader.hasNext())
                {
                    String item = reader.readString();
                    System.out.print(item);
                }
                reader.endArray();
                System.out.print("end " + key);
            }
            else if (key.equals("arraylist"))
            {
                reader.startArray();
                System.out.print("start " + key);
                while (reader.hasNext())
                {
                    reader.startObject();
                    System.out.print("start arraylist item");
                    while (reader.hasNext())
                    {
                        String arrayListItemKey = reader.readString();
                        String arrayListItemValue = reader.readObject().toString();
                        System.out.print("key " + arrayListItemKey);
                        System.out.print("value " + arrayListItemValue);
                    }
                    reader.endObject();
                    System.out.print("end arraylist item");
                }
                reader.endArray();
                System.out.print("end " + key);
            }
            else if (key.equals("object"))
            {
                reader.startObject();
                System.out.print("start object item");
                while (reader.hasNext())
                {
                    String objectKey = reader.readString();
                    String objectValue = reader.readObject().toString();
                    System.out.print("key " + objectKey);
                    System.out.print("value " + objectValue);
                }
                reader.endObject();
                System.out.print("end object item");
            }
            else if (key.equals("string"))
            {
                System.out.print("start string");
                String value = reader.readObject().toString();
                System.out.print("value " + value);
                System.out.print("end string");
            }
        }
        reader.endObject();
        System.out.print("start fastjson");
    }
}