Json数据解析

 1.将Json存储到Sdcard上面

 

package com.demo.lc;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.PrintStream;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.content.Context;
import android.os.Environment;
import android.widget.Toast;

public class WriteSdcard {
    /**存储数据的文件*/
    private File file = null;
    /**文件输出流对象*/
    private FileOutputStream fos = null;
    /**上下文对象*/
    private Context context = null;
    /**文件的路径*/
    private static final String PATH = "JSON";
    /**打印流对象*/
    private PrintStream print = null;
    /**字符串用于存储员工信息*/
    private String content = null;
    /**存储一条员工信息的JSONObject对象*/
    private JSONObject data1 = null;
    /**存储一条员工信息的JSONObject对象*/
    private JSONObject data2 = null;
    /**将所有员工信息存储起来的JSONArray对象*/
    private JSONArray array = null;
    /**两条员工信息*/
    private String[][] member1 = new String[][] { { "id", "B09060236" },
            { "name", "李超" }, { "age", "21" }, { "company", "Tecent" } };
    private String[][] member2 = new String[][] { { "id", "B09060237" },
            { "name", "郭俊峰" }, { "age", "20" }, { "company", "HuaWei" } };
    //构造方法
    public WriteSdcard(Context context) {
        super();
        this.context = context;
    }

    //将员工信息以Json数据的形式写入到Sdcard中
    public void writerInfo() {
        //判读Sdcard是否存在
        if (!(Environment.getExternalStorageState()
                .equals(Environment.MEDIA_MOUNTED))) {
            Toast.makeText(context, "SDcard不存在", Toast.LENGTH_SHORT);
        } else {
            this.file = new File(Environment.getExternalStorageDirectory()
                    + File.separator + WriteSdcard.PATH + File.separator
                    + "json.txt");
            //判读是否存在JSON目录
            if (!file.getParentFile().exists()) {
                this.file.getParentFile().mkdirs();
            }
            //将员工信息写入到sdcard规定 的目录中:mnt/sdcard/JSON/json.txt
            try {
                this.fos = new FileOutputStream(file);
                this.print = new PrintStream(fos);
                this.print.print(prepareContent());
            } catch (FileNotFoundException e) {
                System.out.println("文件不存在");
            }

        }
    }


    private String prepareContent() {
        //实例化JSONObject对象data1
        this.data1 = new JSONObject();
        //实例化JSONObject对象data2
        this.data2 = new JSONObject();
        //实例化JSONArray对象array
        this.array = new JSONArray();
        //将员工1的信息写入到data1中
        put(member1, data1);
        //将员工2的信息写入到data2中
        put(member2, data2);
        //将data1，data2写入到array中
        this.array.put(data1);
        this.array.put(data2);
        //将JSONArray对象转化为String对象
        this.content = this.array.toString();
        return content;
    }

    private void put(String[][] member, JSONObject object) {
        //将员工信息的各个属性放入的JSONObect中
        for (int x = 0; x < member.length; x++) {
            try {
                object.put(member[x][0], member[x][1]);
            } catch (JSONException e) {
                e.printStackTrace();
            }
        }
    }
}

   效果如下：

    

2. 将sdcard上的数据显示以ListView的形式显示到手机上

 

package com.demo.lc;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Scanner;

import org.json.JSONArray;
import org.json.JSONException;

import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ListView;
import android.widget.SimpleAdapter;

public class JSONProjectActivity extends Activity implements OnClickListener {
    /**存储数据的适配器*/
    private SimpleAdapter adapter = null;
    /**存储数据的list*/
    private List> list = null;
    /**显示数据的ListView*/
    private ListView lv = null;
    /**按钮*/
    private Button btn_read = null;
    /**读取文件对象*/
    private FileInputStream fis = null;
    /**文件扫描对象*/
    private Scanner sc = null;
    /**将信息写入到Sdcard上面*/
    private WriteSdcard ws = null;
    /**字符串缓冲对象*/
    private StringBuffer sb = new StringBuffer();

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        super.setContentView(R.layout.main);
        //实例化组件Button，ListView
        this.btn_read = (Button) super.findViewById(R.id.btn_read);
        this.lv = (ListView) super.findViewById(R.id.lv_list);
        //实例化ws对象
        this.ws = new WriteSdcard(this);
        //为按钮注册事件监听对象
        this.btn_read.setOnClickListener(this);

    }

    public void onClick(View v) {
        //将数据写入到Sdcard上面
        this.ws.writerInfo();
        //将数据从Sdcard上面读出并以ListView的形式显示
        read();
    }

    private void read() {
        //实例化list对象
        this.list = new ArrayList>();
        try {
            //实例化文件输入流对象
            fis = new FileInputStream(new File(
                    Environment.getExternalStorageDirectory() + File.separator
                            + "JSON" + File.separator + "json.txt"));
            //实例化sc对象，用于文件的读取
            sc = new Scanner(fis);
            //将文件信息读取到sb中
            while (sc.hasNext()) {
                sb.append(sc.next());
            }
            //关闭文件输入流和扫描流
            fis.close();
            sc.close();
        } catch (FileNotFoundException e) {

            e.printStackTrace();

        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        try {
            //将sb转化为JSONArray对象
            JSONArray jsa = new JSONArray(sb.toString());
            //对获得的JSON数据进行解析
            for (int x = 0; x < jsa.length(); x++) {
                Map map = new HashMap();
                map.put("id", jsa.getJSONObject(x).getString("id"));
                map.put("age", jsa.getJSONObject(x).getString("age"));
                map.put("name", jsa.getJSONObject(x).getString("name"));
                map.put("company", jsa.getJSONObject(x).getString("company"));
                this.list.add(map);
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
        //实例化SimpleAdapter适配器
        this.adapter = new SimpleAdapter(this, this.list, R.layout.listinfo,
                new String[] { "id", "name", "age", "company" },
                new int[] { R.id.tv_id, R.id.tv_name, R.id.tv_age,
                        R.id.tv_company });
        this.adapter
                .setDropDownViewResource(android.R.layout.simple_list_item_checked);
        //为ListView设置设配器
        this.lv.setAdapter(adapter);

    }
}

 效果如下：