无法处理大于65535个字符的字符串文字大小。编译器抛出IllegalArgumentException

Question

我想解码Scala中的Base64编码图像。字符串文字长度超过65535个字符。每当我尝试编译下面的代码时，编译器都会给出一个IllegalArgumentException。

Scala代码：

val data = "/9j/4AAQSkZJRgABAgAAAQABAAD/2wBDAA ... " 
val imageByte = Base64.getDecoder.decode(data)   
val byteArray = new ByteArrayInputStream(imageByte)  
val image = ImageIO.read(byteArray)      
ImageIO.write(image, "jpeg", new File("image.jpeg")) 

编译例外：

Error:scalac: Error:   org.jetbrains.jps.incremental.scala.remote.ServerException 
java.lang.IllegalArgumentException 
at scala.tools.asm.ByteVector.putUTF8(ByteVector.java:213) 
at scala.tools.asm.ClassWriter.newUTF8(ClassWriter.java:1092) 
at scala.tools.asm.ClassWriter.newString(ClassWriter.java:1525) 
at scala.tools.asm.ClassWriter.newConstItem(ClassWriter.java:1042) 
at scala.tools.asm.MethodWriter.visitLdcInsn(MethodWriter.java:1134) 
at scala.tools.nsc.backend.jvm.GenASM$JPlainBuilder.genConstant(GenASM.scala:1582) 
at scala.tools.nsc.backend.jvm.GenASM$JPlainBuilder.scala$tools$nsc$backend$jvm$GenASM$JPlainBuilder$$genInstr$1(GenASM.scala:2296) 
at scala.tools.nsc.backend.jvm.GenASM$JPlainBuilder$$anonfun$genBlock$1$2.apply(GenASM.scala:2227) 
at scala.tools.nsc.backend.jvm.GenASM$JPlainBuilder$$anonfun$genBlock$1$2.apply(GenASM.scala:2213) 
at scala.collection.IndexedSeqOptimized$class.foreach(IndexedSeqOptimized.scala:33) 
at scala.collection.mutable.ArrayOps$ofRef.foreach(ArrayOps.scala:186) 
at scala.tools.nsc.backend.icode.BasicBlocks$BasicBlock.foreach(BasicBlocks.scala:195) 
at scala.tools.nsc.backend.jvm.GenASM$JPlainBuilder.genBlock$1(GenASM.scala:2213) 
at scala.tools.nsc.backend.jvm.GenASM$JPlainBuilder.genBlocks$1(GenASM.scala:2151) 
at scala.tools.nsc.backend.jvm.GenASM$JPlainBuilder.genCode(GenASM.scala:2746) 
at scala.tools.nsc.backend.jvm.GenASM$JPlainBuilder.genMethod(GenASM.scala:1471) 
at scala.tools.nsc.backend.jvm.GenASM$JPlainBuilder.genClass(GenASM.scala:1341) 
at scala.tools.nsc.backend.jvm.GenASM$AsmPhase.emitFor$1(GenASM.scala:198) 
at scala.tools.nsc.backend.jvm.GenASM$AsmPhase.run(GenASM.scala:204) 
at scala.tools.nsc.Global$Run.compileUnitsInternal(Global.scala:1501) 
at scala.tools.nsc.Global$Run.compileUnits(Global.scala:1486) 
at scala.tools.nsc.Global$Run.compileSources(Global.scala:1481) 
at scala.tools.nsc.Global$Run.compile(Global.scala:1582) 
at xsbt.CachedCompiler0.run(CompilerInterface.scala:115) 
at xsbt.CachedCompiler0.run(CompilerInterface.scala:94) 
at xsbt.CompilerInterface.run(CompilerInterface.scala:22) 
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) 
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
at java.lang.reflect.Method.invoke(Method.java:497) 
at sbt.compiler.AnalyzingCompiler.call(AnalyzingCompiler.scala:101) 
at sbt.compiler.AnalyzingCompiler.compile(AnalyzingCompiler.scala:47) 
at sbt.compiler.AnalyzingCompiler.compile(AnalyzingCompiler.scala:41) 
at org.jetbrains.jps.incremental.scala.local.IdeaIncrementalCompiler.compile(IdeaIncrementalCompiler.scala:29) 
at org.jetbrains.jps.incremental.scala.local.LocalServer.compile(LocalServer.scala:26) 
at org.jetbrains.jps.incremental.scala.remote.Main$.make(Main.scala:67) 
at org.jetbrains.jps.incremental.scala.remote.Main$.nailMain(Main.scala:24) 
at org.jetbrains.jps.incremental.scala.remote.Main.nailMain(Main.scala) 
at sun.reflect.GeneratedMethodAccessor3.invoke(Unknown Source) 
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
at java.lang.reflect.Method.invoke(Method.java:497) 
at com.martiansoftware.nailgun.NGSession.run(NGSession.java:319) 

按本bug，我明白的是，根据JVM规范，字节长度大于2个字节的字段更大将不适合。彻底搜索后，我仍然无法找到解决此问题的解决方法，该问题仍然处于活动状态。在Java/Scala中处理长字符串文字可能是一个很好的解决方法。

Answer 1

什么时候文字是这么长，它应该不会被嵌入代码了，因为可读性问题。我会从一个文件/资源​​加载它。

的Java

随着Commons IO这是很容易做到：

String str = IOUtils.toString(this.getClass().getResource("myResource", StandardCharsets.UTF_8); 

在我看来，略少于可读，但如果你真的不想使用任何库，你也可以做到这一点出发从Java 7：

String str = new String(Files.readAllBytes(Paths.get("myResource")), StandardCharsets.UTF_8); 

斯卡拉

斯卡拉你可以使用内置的scala.io.Source类：

val testTxtSource = Source.fromFile("myResource") 
val str = testTxtSource.mkString() 
testTxtSource.close() 

Answer 2

如果您一次可以读取四个字节，那么一旦解码完成，这将对应三个字节。将它们连接在一起，你会得到相同的结果。