不废话，需求：缓存登录时的token，超过设置的存储时间就无效，怎么做？

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。

1,首先，我们需要一个存储的model——SpSaveModelpublic 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;

}

}

2,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'

3,工具类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_UNIT

}

public void set(String e, Object value,int saveTime) {

SpSaveModelspSaveModel=new SpSaveModel<>(saveTime,value,System.currentTimeMillis());

String json=JSON.toJSONString(spSaveModel);

editor.putString(e, json);

editor.commit();

}

}

4，使用public class MainActivity extends AppCompatActivity {

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

findViewById(R.id.btn_save).setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

save();

}

});

findViewById(R.id.btn_get).setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

get();

}

});

}

//保存

private void save() {

//保存10秒

// SpUtils.getInstance(this).set("text","我的世界",10);

SpUtils.getInstance(this).setString("text","我的世界",10);

SpUtils.getInstance(this).setInt("num",123456,10);

SpUtils.getInstance(this).setBoolean("isBu",true,10);

}

//获取

private void get() {

String text=SpUtils.getInstance(this).getString("text","超时了");

int num=SpUtils.getInstance(this).getInt("num",-100);

boolean isBu=SpUtils.getInstance(this).getBoolean("isBu",false);

Log.e("kid","text======="+text);

Log.e("kid","num======="+num);

Log.e("kid","isBu======="+isBu);

}

}

PS：存的时候，不加存储时间，默认是永久