是否可以从 dex 文件中获取特定行的 java 代码？

Question

I am trying to analyse dex files, and I want to know if I can get the java code or what a specific bytes from the dex file mean.

Any help will be appreciated!

Answer 1

Getting java code from bytecode is called decompilation, and you will need to use a decompiler. Although I'm not aware of any decompiler that will do partial decompilation of just a snippet of bytecode. There may not even be enough info in that snippet to perform a proper decompilation.

"Or what specific bytes from the dex file mean" - you could try using baksmali's annotated dump functionality. It writes out a format that has the binary bytes on the left side, and a structured text view on the right side corresponding to the bytes on the left side.

eg baksmali dump HelloWorld.dex

...
                           |-----------------------------
                           |code_item section
                           |-----------------------------
                           |
                           |[0] code_item: LHelloWorld;->main([Ljava/lang/String
                           |;)V
0001c4: 0200               |  registers_size = 2
0001c6: 0100               |  ins_size = 1
0001c8: 0200               |  outs_size = 2
0001ca: 0000               |  tries_size = 0
0001cc: 0000 0000          |  debug_info_off = 0x0
0001d0: 0800 0000          |  insns_size = 0x8
                           |  instructions:
0001d4: 6200 0000          |    sget-object v0, Ljava/lang/System;->out:Ljava/io
                           |/PrintStream;
0001d8: 1a01 0000          |    const-string v1, "Hello World!"
0001dc: 6e20 0100 1000     |    invoke-virtual {v0, v1}, Ljava/io/PrintStream;->
                           |println(Ljava/lang/String;)V
0001e2: 0e00               |    return-void
...

On the left side we have [offset]: [binary data] and then the right side has the interpreted view. eg field name and value, or disassembled instruction, etc.