class 文件java字节码Oolong反编译分析

悠悠 2022-07-14 08:48 229阅读 0赞

我们知道java程序在经过虚拟机后生成class字节码二进制文件，那么怎样分析class文件呢，我们可以把class文件结构转换为能够理解的汇编语言Oolong，可以更好的认识class文件中的信息。

**一：下载Onlong JVM项目**

地址https://github.com/jpbirdy/programming-for-the-jvm

**主要说明**

\* COM.sootNsmoke.jvm - a library for building Java (tm)  class files  
\* COM.sootNsmoke.oolong - A compiler and decompiler for Oolong, a  
  language for building JVM class files.  
\* COM.sootNsmoke.instructions - Support classes for the jvm package.  
  Abstractions of JVM instructions to make building code easier.  
\* COM.sootNsmoke.scheme - a nearly complete implementation of the R4  
  Scheme specification, which compiles Scheme code into JVM bytecodes.  
\* COM.sootNsmoke.prolog - a simple Prolog compiler demonstrating how  
  to compile Prolog into JVM code

**二：把Onlong文件下的\\programming-for-the-jvm-master\\src\\main\\java\\COM打为jar包**

**![Center][]**

**三：把jar包放到jdk的lib目录下并添加到环境变量的classpath路径下**

**![Center 1][]**

**四：测试生成Onlong**

**![Center 2][]**

**五：生成了.j结尾的文件**

**![Center 3][]**

**六：对.j结尾Onlong的文件进行分析**

.source TestClass.java
    .class public super com/lean/clazz/TestClass
    .super java/lang/Object
    
    
    .method public <init> ()V
    .limit stack 1
    .limit locals 1
    .var 0 is this Lcom/lean/clazz/TestClass; from l0 to l5
    .line 3
    l0:    aload_0
    l1:    invokespecial java/lang/Object/<init> ()V
    l4:    return
    
    .end method
    
    .method public static main ([Ljava/lang/String;)V
    .limit stack 2
    .limit locals 1
    .var 0 is args [Ljava/lang/String; from l0 to l9
    .line 5
    l0:    getstatic java/lang/System/out Ljava/io/PrintStream;
    l3:    ldc "I am Chinese!"
    l5:    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    .line 6
    l8:    return
    
    .end method

[Center]: /images/20220714/d6179df3d02f44e2a1c30f4973f72fb3.png
[Center 1]: /images/20220714/1d6a69dd016d40c3aaded55fa527c389.png
[Center 2]: /images/20220714/febb5bc6832641cbb909ac1019d37d4e.png
[Center 3]: /images/20220714/7ffb20a2fbe249bc8eadb75d5b0ea25d.png