每次请求回的Json数据本地用sharedpreference保存

package com.lonshin.chexiaodi.http;

import java.util.Date;
import java.util.List;
import java.util.Set;
import java.util.Timer;
import java.util.TimerTask;
import java.util.TreeSet;

import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;

import com.krislq.sliding.MyApplication;

import android.content.Context;
import android.content.ContextWrapper;
import android.content.SharedPreferences;
import android.util.Log;
/**
 * to check if the local JSONResult exist
 * 
 * and do the write and read
 * @author linsen
 *
 */


public class SPTool { 
    SharedPreferences sp;
    SharedPreferences.Editor  editor;
    
    private SPTool(){
        sp = MyApplication.getInstance().getSharedPreferences("Result", Context.MODE_WORLD_READABLE);                
        editor = sp.edit();
        
        
    }
    
    private static SPTool instance = new SPTool(){};
    
    public static SPTool getInstance(){
        return instance;
    }
    /**
     * 判断是否有本地json 而且是没过期的
     * 
     * @return
     */
    public boolean hasSDResult(List<NameValuePair> params){ 
//        Log.d("httplocal-in Sdjr",String.valueOf(sp.contains(params.toString())));
        long oldT = 0;
        long newT = 0;
        
        //取得保存的String当时的时间oldT
        if(sp.contains(params.toString())){
            String s = sp.getString(params.toString(), null);
            if(s.contains("#")){
                String[] str = s.split("#");            
                oldT = Long.parseLong(str[0]);    
                newT = new Date().getTime();
            }
        }
        
        //设置过期时间为1小时---若测试用则设为3秒
        if(((newT-oldT)<5000)&&((newT-oldT)>0)){
            return true;
        }else{
            editor.remove(params.toString());
            return false;
        }

        
    }
    
    /**
     * 访问结果访问到本地
     * @param params
     * @param result
     */
    public void saveToSD(List<NameValuePair> params , String result){
        
        //在保存的String中增加一个time及符号"#"
        String time = String.valueOf(new Date().getTime());
        String result01 = time+"#"+result;
        editor.putString(params.toString(), result01);
        editor.commit();
        Log.d("httplocal-in Sdjr","saveToSD"+params.toString());
    }
    
    /**
     * 获取本地保存的访问结果
     * @param params
     * @return
     */
    public String getSDResult(List<NameValuePair> params){        
        Log.d("httplocal" , "getSDResult");
        String s = sp.getString(params.toString(), null);
        
        //取得数据时,去掉附加的time信息
        if(s.contains("#")){
            String[] str = s.split("#");
            
            return str[1]; 
        }else{
            return s;
        }        
    }    
}