看了下《深入虚拟机》相关章节,还是存在一些字节码的疑惑 - V2EX
xyooyx
V2EX    Java

看了下《深入虚拟机》相关章节,还是存在一些字节码的疑惑

  •  1
     
  •   xyooyx Apr 21, 2020 2457 views
    This topic created in 2212 days ago, the information mentioned may be changed or developed.
    • 前几天咨询了大家字节码相关问题

    • 看了一遍《深入理解虚拟机》,部分指令和语法是明白了,但是依然存在一些疑惑

    • 在下面字节码中标出了,麻烦懂的朋友指点下

    • 多谢了

    • 类文件

    package core.object_create; public class ObjectTest { private String name="v2"; public void hi(){ int i =777; } } 
    • 字节码
    // class version 56.0 (56) // access flags 0x21 public class core/object_create/ObjectTest { // compiled from: ObjectTest.java // access flags 0x2 private Ljava/lang/String; name // access flags 0x1 public <init>()V L0 //这里在申明什么 LINENUMBER 3 L0 //这个语法是啥意思 ALOAD 0 INVOKESPECIAL java/lang/Object.<init> ()V L1 LINENUMBER 4 L1 ALOAD 0 LDC "v2" PUTFIELD core/object_create/ObjectTest.name : Ljava/lang/String; RETURN L2 LOCALVARIABLE this Lcore/object_create/ObjectTest; L0 L2 0 MAXSTACK = 2 MAXLOCALS = 1 // access flags 0x1 public hi()V L0 LINENUMBER 7 L0 SIPUSH 777 ISTORE 1 L1 LINENUMBER 8 L1 RETURN L2 LOCALVARIABLE this Lcore/object_create/ObjectTest; L0 L2 0 //这句 LOCALVARIABLE i I L1 L2 1 //以及这句分别在申明什么 MAXSTACK = 1 MAXLOCALS = 2 } 
    2 replies    2020-04-22 15:50:00 +08:00
    penguinWWY
        1
    penguinWWY  
       Apr 22, 2020   1
    你用的字节码查看工具把 LineNumberTable 和 LocalVariableTable 这两个表的内容解析了一下
    L0 、L1 应该表示一个 label,也就是一个标签
    `LINENUMBER ` 声明这个标签对应的行号
    `LOCALVARIABLE` 表示局部变量的名字、类型
    xyooyx
        2
    xyooyx  
    OP
       Apr 22, 2020
    @penguinWWY 感谢
    About     Help     Advertise     Blog     API     FAQ     Solana     5671 Online   Highest 6679       Select Language
    创意工作者们的社区
    World is powered by solitude
    VERSION: 3.9.8.5 34ms UTC 03:34 PVG 11:34 LAX 20:34 JFK 23:34
    Do have faith in what you're doing.
    ubao msn snddm index pchome yahoo rakuten mypaper meadowduck bidyahoo youbao zxmzxm asda bnvcg cvbfg dfscv mmhjk xxddc yybgb zznbn ccubao uaitu acv GXCV ET GDG YH FG BCVB FJFH CBRE CBC GDG ET54 WRWR RWER WREW WRWER RWER SDG EW SF DSFSF fbbs ubao fhd dfg ewr dg df ewwr ewwr et ruyut utut dfg fgd gdfgt etg dfgt dfgd ert4 gd fgg wr 235 wer3 we vsdf sdf gdf ert xcv sdf rwer hfd dfg cvb rwf afb dfh jgh bmn lgh rty gfds cxv xcv xcs vdas fdf fgd cv sdf tert sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf shasha9178 shasha9178 shasha9178 shasha9178 shasha9178 liflif2 liflif2 liflif2 liflif2 liflif2 liblib3 liblib3 liblib3 liblib3 liblib3 zhazha444 zhazha444 zhazha444 zhazha444 zhazha444 dende5 dende denden denden2 denden21 fenfen9 fenf619 fen619 fenfe9 fe619 sdf sdf sdf sdf sdf zhazh90 zhazh0 zhaa50 zha90 zh590 zho zhoz zhozh zhozho zhozho2 lislis lls95 lili95 lils5 liss9 sdf0ty987 sdft876 sdft9876 sdf09876 sd0t9876 sdf0ty98 sdf0976 sdf0ty986 sdf0ty96 sdf0t76 sdf0876 df0ty98 sf0t876 sd0ty76 sdy76 sdf76 sdf0t76 sdf0ty9 sdf0ty98 sdf0ty987 sdf0ty98 sdf6676 sdf876 sd876 sd876 sdf6 sdf6 sdf9876 sdf0t sdf06 sdf0ty9776 sdf0ty9776 sdf0ty76 sdf8876 sdf0t sd6 sdf06 s688876 sd688 sdf86