Java 无法从文件中读回protobuff
我正在将一个Java 无法从文件中读回protobuff,java,android,protocol-buffers,Java,Android,Protocol Buffers,我正在将一个protobuf写入文件,然后再次读取如下内容 原抛光块 Person personOne = Person.newBuilder() .setId(1234) .setName("John Doe") .setEmail("jdoe@example.com") .addPhone(
protobuf
写入文件,然后再次读取如下内容
原抛光块
Person personOne =
Person.newBuilder()
.setId(1234)
.setName("John Doe")
.setEmail("jdoe@example.com")
.addPhone(
Person.PhoneNumber.newBuilder()
.setNumber("555-4321")
.setType(Person.PhoneType.HOME))
.build();
写入文件时,这里的数据
是字节[]
,参数是personOne.toByteArray()
从文件中读取,但在读取时,我遇到错误
try {
FileInputStream input = new FileInputStream(file);
byte [] buffer = new byte[input.read()];
input.read(buffer);
input.close();
return buffer;
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
错误
03-20 21:04:39.060: W/System.err(18074): com.google.protobuf.InvalidProtocolBufferException: Protocol message tag had invalid wire type.
03-20 21:04:39.090: W/System.err(18074): at com.google.protobuf.UnknownFieldSet$Builder.mergeFieldFrom(UnknownFieldSet.java:498)
03-20 21:04:39.110: W/System.err(18074): at com.google.protobuf.GeneratedMessage.parseUnknownField(GeneratedMessage.java:193)
03-20 21:04:39.110: W/System.err(18074): at com.example.protodemo.AddressBookProtos$Person.<init>(AddressBookProtos.java:124)
03-20 21:04:39.110: W/System.err(18074): at com.example.protodemo.AddressBookProtos$Person.<init>(AddressBookProtos.java:107)
03-20 21:04:39.110: W/System.err(18074): at com.example.protodemo.AddressBookProtos$Person$1.parsePartialFrom(AddressBookProtos.java:186)
03-20 21:04:39.110: W/System.err(18074): at com.example.protodemo.AddressBookProtos$Person$1.parsePartialFrom(AddressBookProtos.java:1)
03-20 21:04:39.110: W/System.err(18074): at com.google.protobuf.AbstractParser.parsePartialFrom(AbstractParser.java:141)
03-20 21:04:39.110: W/System.err(18074): at com.google.protobuf.AbstractParser.parseFrom(AbstractParser.java:176)
03-20 21:04:39.110: W/System.err(18074): at com.google.protobuf.AbstractParser.parseFrom(AbstractParser.java:188)
03-20 21:04:39.110: W/System.err(18074): at com.google.protobuf.AbstractParser.parseFrom(AbstractParser.java:193)
03-20 21:04:39.110: W/System.err(18074): at com.google.protobuf.AbstractParser.parseFrom(AbstractParser.java:49)
03-20 21:04:39.120: W/System.err(18074): at com.example.protodemo.AddressBookProtos$Person.parseFrom(AddressBookProtos.java:1088)
03-20 21:04:39.120: W/System.err(18074): at com.example.protodemo.MainActivity.onCreate(MainActivity.java:63)
03-20 21:04:39.120: W/System.err(18074): at android.app.Activity.performCreate(Activity.java:4470)
03-20 21:04:39.120: W/System.err(18074): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1053)
03-20 21:04:39.120: W/System.err(18074): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1934)
03-20 21:04:39.120: W/System.err(18074): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1995)
03-20 21:04:39.120: W/System.err(18074): at android.app.ActivityThread.access$600(ActivityThread.java:128)
03-20 21:04:39.120: W/System.err(18074): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1161)
03-20 21:04:39.120: W/System.err(18074): at android.os.Handler.dispatchMessage(Handler.java:99)
03-20 21:04:39.120: W/System.err(18074): at android.os.Looper.loop(Looper.java:137)
03-20 21:04:39.120: W/System.err(18074): at android.app.ActivityThread.main(ActivityThread.java:4517)
03-20 21:04:39.120: W/System.err(18074): at java.lang.reflect.Method.invokeNative(Native Method)
03-20 21:04:39.120: W/System.err(18074): at java.lang.reflect.Method.invoke(Method.java:511)
03-20 21:04:39.130: W/System.err(18074): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:993)
03-20 21:04:39.130: W/System.err(18074): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:760)
03-20 21:04:39.130: W/System.err(18074): at dalvik.system.NativeStart.main(Native Method)
从您的代码:
byte [] buffer = new byte[input.read()];
这里,您似乎正在读取输入的第一个字节,并将其用作缓冲区的大小。但是,当您编写文件时,实际上并没有在第一个字节中写入大小;您只编写了以下数据:
FileOutputStream output = new FileOutputStream(file);
output.write(data);
output.close();
不要将文件内容读取到字节[]
,只需将输入流本身传递到parseFrom
,如:
FileInputStream input = new FileInputStream(file);
Person person = Person.parseFrom(input);
如果必须读入字节数组,则根据文件的实际大小分配数组,例如使用
file#length()
。或者,在写消息之前先写消息大小。(不过,不要只写一个字节,因为如果你的消息大于255字节,你会遇到问题。)我使用的是android,它使用的是java.io.File
,而Dalvik仍然没有使用java 7?听起来很奇怪,我只使用JRE7,我刚刚在eclipsei中看到我的项目文件->android.provider.MediaStore
@fge:Files不在android中。你的评论与问题无关。
FileOutputStream output = new FileOutputStream(file);
output.write(data);
output.close();
FileInputStream input = new FileInputStream(file);
Person person = Person.parseFrom(input);