Java 将对象读写到android文件(ObjectOutput/InputStream)
我试图从一个文件中读取对象并将它们添加到一个向量中,但我一直得到一个错误,我不知道为什么。 以下是阅读功能:Java 将对象读写到android文件(ObjectOutput/InputStream),java,android,objectinputstream,objectoutputstream,Java,Android,Objectinputstream,Objectoutputstream,我试图从一个文件中读取对象并将它们添加到一个向量中,但我一直得到一个错误,我不知道为什么。 以下是阅读功能: public Vector<Paciente> listaPacientes (int cantidad){ Vector<Paciente> result= new Vector<Paciente>(); try{ FileInputStream f=context.openFileInput(FICHERO);
public Vector<Paciente> listaPacientes (int cantidad){
Vector<Paciente> result= new Vector<Paciente>();
try{
FileInputStream f=context.openFileInput(FICHERO);
ObjectInputStream is = new ObjectInputStream(f);
int n=0;
Paciente pac;
do{
pac=(Paciente) is.readObject();
if(pac!=null){
result.add(pac);
n++;
Log.d("Número n","n="+n);
}
}while(n<cantidad && pac!=null);
f.close();
}catch(Exception e){
Log.e("Historial Clinico", e.getMessage(),e);
}
return result;
}
public void guardarPacientes(Paciente pac){
File file=new File(FICHERO);
if(file.exists()){
try {
FileOutputStream fi = context.openFileOutput(FICHERO, Context.MODE_APPEND);
AppendingObject os=new AppendingObject(fi);
os.writeObject(os);
os.flush();
os.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
else
{
try{
FileOutputStream f=context.openFileOutput(FICHERO, Context.MODE_APPEND);
ObjectOutputStream os = new ObjectOutputStream(f);
os.writeObject(pac);
os.flush();
os.close();
}catch (Exception e){
Log.e("Historial Clinico",e.getMessage(),e);
}
}
}
如您所见,如果文件已经存在,我将从另一个类实例化,以避免使用头。
下面是另一个类:
public class AppendingObject extends ObjectOutputStream{
public AppendingObject(OutputStream out) throws IOException {
super(out);
}
@Override
protected void writeStreamHeader() throws IOException {
reset();
}
以下是错误:
08-0219:21:46.365:E/历史临床医生(32309):格式错误:ac
08-02 19:21:46.365:E/Historial Clinico(32309):java.io.StreamCorruptedException:格式错误:ac
08-02 19:21:46.365:E/历史临床医生(32309):在java.io.ObjectInputStream.corruptStream(ObjectInputStream.java:701)
08-02 19:21:46.365:E/Historial Clinico(32309):位于java.io.ObjectInputStream.readNonPrimitiveContent(ObjectInputStream.java:814)
08-02 19:21:46.365:E/Historial Clinico(32309):位于java.io.ObjectInputStream.readObject(ObjectInputStream.java:2006)
08-02 19:21:46.365:E/Historial Clinico(32309):位于java.io.ObjectInputStream.readObject(ObjectInputStream.java:1963)
08-02 19:21:46.365:E/Historial Clinico(32309):在com.example.historicalinica.PacientestoFile.listapatientes(PacientestoFile.java:60)
08-02 19:21:46.365:E/Historial Clinico(32309):在com.example.historicalinica.cListaPacientes.onCreate(cListaPacientes.java:17)
08-02 19:21:46.365:E/Historial Clinico(32309):在android.app.Activity.performCreate(Activity.java:5372)
08-02 19:21:46.365:E/Historial Clinico(32309):在android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1104)
08-02 19:21:46.365:E/Historial Clinico(32309):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2267)
08-02 19:21:46.365:E/Historial Clinico(32309):在android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2359)
08-02 19:21:46.365:E/Historial Clinico(32309):在android.app.ActivityThread.access$700(ActivityThread.java:165)
08-02 19:21:46.365:E/Historial Clinico(32309):在android.app.ActivityThread$H.handleMessage(ActivityThread.java:1326)
08-02 19:21:46.365:E/Historial Clinico(32309):在android.os.Handler.dispatchMessage(Handler.java:99)上
08-02 19:21:46.365:E/历史临床医生(32309):在android.os.Looper.loop(Looper.java:137)
08-02 19:21:46.365:E/Historial Clinico(32309):位于android.app.ActivityThread.main(ActivityThread.java:5455)
08-02 19:21:46.365:E/Historial Clinico(32309):位于java.lang.reflect.Method.Invokenactive(本机方法)
08-02 19:21:46.365:E/Historial Clinico(32309):位于java.lang.reflect.Method.invoke(Method.java:525)
08-02 19:21:46.365:E/Historial Clinico(32309):位于com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1187)
08-02 19:21:46.365:E/Historial Clinico(32309):位于com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003)
08-02 19:21:46.365:E/历史临床医生(32309):在dalvik.system.NativeStart.main(本机方法)
发生EOFEException是因为您到达了文件的末尾。这很正常。抓住它并打破它。您的代码似乎假定readObject()在文件末尾返回null。没有。如果您写入null,它将返回null。看起来您正在读取由早期版本的代码生成的文件,该代码没有附加流。我已经尝试重命名该文件并删除现有文件,但两种方式都不起作用。哦,我再次尝试重命名该文件,但现在出现了EOFEException错误不一定,你可以在外面接住它,这样可以省去“休息”的时间。你能给我举个我应该如何使用它的例子吗?请