确定.class文件是否已使用调试信息进行编译？ [英] Determine whether .class file was compiled with debug info?

问题描述

如何确定任何Java .class文件是否是用调试信息编译的？

How can I determine for any Java .class file if that was compiled with debug info or not?

如何确切地知道-g {source | lines | vars}选项被使用？

How can I tell exactly what -g{source|lines|vars} option was used?

推荐答案

如果你在命令行，那么javap -l将显示LineNumberTable和LocalVariableTable如果存在：

If you're on the command line, then javap -l will display LineNumberTable and LocalVariableTable if present:

peregrino:$ javac -d bin -g:none src/Relation.java 
peregrino:$ javap -classpath bin -l Relation 
public class Relation extends java.lang.Object{
public Relation();

peregrino:$ javac -d bin -g:lines src/Relation.java 
peregrino:$ javap -classpath bin -l Relation 
public class Relation extends java.lang.Object{
public Relation();
  LineNumberTable: 
   line 1: 0
   line 33: 4

peregrino:$ javac -d bin -g:vars src/Relation.java 
peregrino:$ javap -classpath bin -l Relation 
public class Relation extends java.lang.Object{
public Relation();

  LocalVariableTable: 
   Start  Length  Slot  Name   Signature
   0      5      0    this       LRelation;

javap -c 将显示源文件如果在反编译开始时存在：

javap -c will display the source file if present at the start of the decompilation:

peregrino:$ javac -d bin -g:none src/Relation.java 
peregrino:$ javap -classpath bin -l -c Relation | head
public class Relation extends java.lang.Object{
  ...

peregrino:$ javac -d bin -g:source src/Relation.java 
peregrino:$ javap -classpath bin -l -c Relation | head
Compiled from "Relation.java"
public class Relation extends java.lang.Object{
  ...

以程式设计，我会参考 ASM ，而不是写作还有另一个字节码阅读器。

Programmatically, I'd look at ASM rather than writing yet another bytecode reader.

这篇关于确定.class文件是否已使用调试信息进行编译？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！