从我的搜索来看，我认为这是对我的问题的一个很好的总结。也许，我错误地序列化或反序列化对象？或者如果序列化是正确的，我的问题是否有修复/解决方法？
我一直用这个作为Win32MediaSize类的参考。Win32MediaSize关于引用的类，我还有另一个稍微相关的问题。请参阅从 1640 开始的代码，它是静态初始化程序。我试图重现它，以便我可以看到执行顺序：
public clsss Why {
static {
String a = "Hello";
}
public class Not {
static { // gives me a Cannot define static initializer in inner type error
String b = "World";
}
}
}
这不是主要问题，但如果有人能在这里阐明一下，那就太好了。我个人认为这是问题所在，Win32MediaSize但我不知道为什么。我还尝试了他们在第 85 行和双括号上所做的事情，但都不起作用。删除关键字static确实可以解决错误，但我认为根据我的理解会产生不同的行为。
基本问题是我需要getSupportedAttributeValues为每个 PrintService 执行才能读取序列化数据，这违背了序列化数据的目的。序列化数据的原因是getSupportedAttributeValues完成时间太长（40 多秒）。
这是一个例外（value和range取决于PrintService已加载的距离 - 在实际程序中，它正在另一个线程中加载；请参阅this以供参考）：
java.io.InvalidObjectException: Integer value = 124 not in valid range 0..3for class class sun.print.Win32MediaSize
at javax.print.attribute.EnumSyntax.readResolve(EnumSyntax.java:184)
at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at java.io.ObjectStreamClass.invokeReadResolve(ObjectStreamClass.java:1056)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1761)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328)
at java.io.ObjectInputStream.readArray(ObjectInputStream.java:1666)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1322)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:350)
at java.util.HashMap.readObject(HashMap.java:1030)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:969)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1848)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1752)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:350)
at com.iii.print.PrintServiceLoader.readCachedData(PrintServiceLoader.java:355)
at com.iii.print.PrintServiceLoader.main(PrintServiceLoader.java:420)
这是相关的代码位：
方法works()，fails()这就是我遇到的问题。
void works() {
HashMap<String, Object> m = null;
HashMap<String, Object> mpa = null;
doLookup(); // this is what causes the following call to not fail
m = readCachedData( "a" );
mpa = readCachedData( "b" );
}
void fails() {
/* Assuming the files have already been created */
HashMap<String, Object> m = null;
HashMap<String, Object> mpa = null;
m = readCachedData( "a" ); // this fails (see exception)
mpa = readCachedData( "b" ); // this will work just fine
}
void doLookup() {
PrintService[] psList = PrintServiceLookup.lookupPrintServices( DocFlavor.SERVICE_FORMATTED.PRINTABLE, null );
HashMap<String, Object> cachedMedia = new HashMap<String, Object>();
HashMap<String, Object> cachedMediaPrintableArea = new HashMap<String, Object>();
for ( PrintService ps : psList ) {
Object media = ps.getSupportedAttributeValues( Media.class, null, null );
Object mediaPrintableArea = ps.getSupportedAttributeValues( MediaPrintableArea.class, null, null );
cachedMedia.put( ps.getName(), media );
cachedMediaPrintableArea.put( ps.getName(), mediaPrintableArea );
}
writeCachedData( "a", cachedMedia );
writeCachedData( "b", cachedMediaPrintableArea );
}
boolean writeCachedData( String filename, Map<String, Object> data ) {
boolean successful = true;
if ( filename != null && !filename.isEmpty() && data != null && !data.isEmpty() ) {
FileOutputStream fileOutStream = null;
ObjectOutputStream objOutStream = null;
try {
fileOutStream = new FileOutputStream( filename );
objOutStream = new ObjectOutputStream( fileOutStream );
objOutStream.writeObject( data );
} catch ( FileNotFoundException e ) {
e.printStackTrace();
successful = false;
} catch ( IOException e ) {
e.printStackTrace();
successful = false;
} finally {
try {
if ( objOutStream != null ) {
objOutStream.close();
}
} catch ( IOException e ) {
e.printStackTrace();
successful = false;
}
try {
if ( fileOutStream != null ) {
fileOutStream.close();
}
} catch ( IOException e ) {
e.printStackTrace();
successful = false;
}
}
} else {
successful = false;
}
return successful;
}
Map<String, Object> readCachedData( String filename ) {
Map<String, Object> cachedData = null;
if ( filename != null && !filename.isEmpty() ) {
File f = new File( ".", filename );
if ( f.exists() ) {
FileInputStream fileInStream = null;
ObjectInputStream objInStream = null;
try {
fileInStream = new FileInputStream( f );
objInStream = new ObjectInputStream( fileInStream );
cachedData = (Map<String, Object>) objInStream.readObject();
} catch ( FileNotFoundException e ) {
e.printStackTrace();
} catch ( IOException e ) {
e.printStackTrace();
} catch ( ClassNotFoundException e ) {
e.printStackTrace();
} finally {
try {
if ( fileInStream != null ) {
fileInStream.close();
}
} catch ( IOException e ) {
e.printStackTrace();
}
try {
if ( objInStream != null ) {
objInStream.close();
}
} catch ( IOException e ) {
e.printStackTrace();
}
}
}
}
return cachedData;
}
如您所知，我在 Windows 7 x64 上并使用 jdk 1.6.0_31。如果我遗漏了相关信息，请告诉我。