Android SharedPreferences工具类，可设置缓存时间

使用ACache也可以设置缓存时间，但ACache在清缓存的时候会被清空。
SharedPreferences存储默认都是无时间限制的。
大概思路是，存储的时候记录当前时间，要存多久。取数据的时候判断这个数据已经存储了多久，如果超过设置的存储时间，就获取默认值。
首先，我们需要一个存储的model——SpSaveModel

public class SpSaveModel implements Serializable{
    private int saveTime;
    private T value;
    private long currentTime;

    public SpSaveModel() {
    }

    public SpSaveModel(int saveTime, T value,long currentTime) {
        this.saveTime = saveTime;
        this.value = value;
        this.currentTime=currentTime;
    }

    public long getCurrentTime() {
        return currentTime;
    }

    public void setCurrentTime(long currentTime) {
        this.currentTime = currentTime;
    }

    public int getSaveTime() {
        return saveTime;
    }

    public void setSaveTime(int saveTime) {
        this.saveTime = saveTime;
    }

    public T getValue() {
        return value;
    }

    public void setValue(T value) {
        this.value = value;
    }
}

需要一个object和json字符串转换的工具，这里用fastJson，添加依赖

    compile 'com.alibaba:fastjson:1.1.26'

import android.content.Context;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.text.TextUtils;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.TypeReference;

/**
 * Created by KID on 2018/5/3.
 */
public class SpUtils {
    //保存时间单位
    public static final int TIME_SECOND=1;
    public static final int TIME_MINUTES=60*TIME_SECOND;
    public static final int TIME_HOUR = 60 *TIME_MINUTES;
    public static final int TIME_DAY = TIME_HOUR * 24;
    public static final int TIME_MAX = Integer.MAX_VALUE; // 不限制存放数据的数量
    public static final int DURATION_UNIT=1000;

    private static final String fileName = "config";
    private SharedPreferences sp;
    private Editor editor;

    private static SpUtils INSTANCE = null;

    public static SpUtils getInstance(Context context) {
        if (null == INSTANCE) {
            INSTANCE = new SpUtils(context);
        }
        return INSTANCE;
    }
    private SpUtils(Context context) {
        sp = context.getSharedPreferences(fileName, Context.MODE_PRIVATE);
        editor = sp.edit();
    }


    public void setString(String e, String value) {
        SpSaveModelspSaveModel=new SpSaveModel<>(TIME_MAX,value,System.currentTimeMillis());
        String json=JSON.toJSONString(spSaveModel);
        editor.putString(e, json);
        editor.commit();
    }

    /**
     *
     * @param e  存放的key
     * @param value 存放的value
     * @param saveTime 缓存时间
     */
    public void setString(String e, String value,int saveTime) {
        SpSaveModelspSaveModel=new SpSaveModel<>(saveTime,value,System.currentTimeMillis());
        String json=JSON.toJSONString(spSaveModel);
        editor.putString(e, json);
        editor.commit();
    }

    /**
     *
     * @param e 存放的key
     * @param defValue 该key不存在或者过期时，返回的默认值
     * @return
     */
    public String getString(String e, String defValue){
        String json=sp.getString(e,"");
        if(!TextUtils.isEmpty(json)){
            SpSaveModelspSaveModel= JSON.parseObject(json, new TypeReference>(){});
            if(isTimeOut(spSaveModel.getCurrentTime(),spSaveModel.getSaveTime())){
                return spSaveModel.getValue();
            }
        }
        return defValue;
    }

    public void setInt(String e, int value) {
        SpSaveModelspSaveModel=new SpSaveModel<>(TIME_MAX,value,System.currentTimeMillis());
        String json=JSON.toJSONString(spSaveModel);
        editor.putString(e, json);
        editor.commit();
    }

    public void setInt(String e, int value,int saveTime) {
        SpSaveModelspSaveModel=new SpSaveModel<>(saveTime,value,System.currentTimeMillis());
        String json=JSON.toJSONString(spSaveModel);
        editor.putString(e, json);
        editor.commit();
    }

    public Integer getInt(String e, int defValue){
        String json=sp.getString(e,"");
        if(!TextUtils.isEmpty(json)){
            SpSaveModelspSaveModel= JSON.parseObject(json, new TypeReference>(){});
            if(isTimeOut(spSaveModel.getCurrentTime(),spSaveModel.getSaveTime())){
                return spSaveModel.getValue();
            }
        }
        return defValue;
    }

    public void setBoolean(String e, boolean value) {
        SpSaveModelspSaveModel=new SpSaveModel<>(TIME_MAX,value,System.currentTimeMillis());
        String json=JSON.toJSONString(spSaveModel);
        editor.putString(e, json);
        editor.commit();
    }

    public void setBoolean(String e, boolean value,int saveTime) {
        SpSaveModelspSaveModel=new SpSaveModel<>(saveTime,value,System.currentTimeMillis());
        String json=JSON.toJSONString(spSaveModel);
        editor.putString(e, json);
        editor.commit();
    }

    public boolean getBoolean(String e, boolean defValue){
        String json=sp.getString(e,"");
        if(!TextUtils.isEmpty(json)){
            SpSaveModelspSaveModel= JSON.parseObject(json, new TypeReference>(){});
            if(isTimeOut(spSaveModel.getCurrentTime(),spSaveModel.getSaveTime())){
                return spSaveModel.getValue();
            }
        }
        return defValue;
    }

    public void setLong(String e, long value) {
        SpSaveModelspSaveModel=new SpSaveModel<>(TIME_MAX,value,System.currentTimeMillis());
        String json=JSON.toJSONString(spSaveModel);
        editor.putString(e, json);
        editor.commit();
    }

    public void setLong(String e, long value,int saveTime) {
        SpSaveModelspSaveModel=new SpSaveModel<>(saveTime,value,System.currentTimeMillis());
        String json=JSON.toJSONString(spSaveModel);
        editor.putString(e, json);
        editor.commit();
    }

    public long getLong(String e, long defValue){
        String json=sp.getString(e,"");
        if(!TextUtils.isEmpty(json)){
            SpSaveModelspSaveModel= JSON.parseObject(json, new TypeReference>(){});
            if(isTimeOut(spSaveModel.getCurrentTime(),spSaveModel.getSaveTime())){
                return spSaveModel.getValue();
            }
        }
        return defValue;
    }

    public boolean isTimeOut(long saveCurrentTime,int saveTime){
        return  (System.currentTimeMillis()-saveCurrentTime)/DURATION_UNITpublic void set(String e, Object value,int saveTime) {
        SpSaveModel