共享文件也是进程间通信的方式,两个进程通过读写同一个文件来交换数据。其局限性在于如果是并发读写时,内容有可能不是最新的,应该尽量避免这种情况或者使用线程同步在限制多个线程的写操作。
使用方法:
/**
* 写
**/
private void persistToFile(){
new Thread(new Runnable() {
@Override
public void run() {
User user = new User(1,"hello world",false);//User实现了Serializable接口
String printTxtPath = getApplicationContext().getFilesDir().getAbsolutePath();
File dir = new File(printTxtPath + "/user");
if(!dir.exists()){
dir.mkdirs();
}
File cachedFile = new File(dir.getAbsolutePath()+"/user.txt");
ObjectOutputStream objectOutputStream = null;
try {
objectOutputStream = new ObjectOutputStream(new FileOutputStream(cachedFile));
objectOutputStream.writeObject(user);
Log.d(TAG,"存储的user:" + user.toString());
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (objectOutputStream != null) {
objectOutputStream.flush();
objectOutputStream.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
}).start();
}
/**
* 读
**/
private void recoverFromFile(){
new Thread(new Runnable() {
@Override
public void run() {
User user = null;
String printTxtPath = getApplicationContext().getFilesDir().getAbsolutePath()+"/user";
File cachedFile = new File(printTxtPath + "/user.txt");
if(cachedFile.exists()){
ObjectInputStream objectInputStream = null;
try {
objectInputStream = new ObjectInputStream(new FileInputStream(cachedFile));
user = (User) objectInputStream.readObject();
Log.d(TAG,"读取到的user:" + user.toString());
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (StreamCorruptedException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
}finally {
try {
if(objectInputStream!=null){
objectInputStream.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}).start();
}