如何反编译Java

我想要一种简单的方法来反编译Java。 我想检查一下javac编译器对我的代码所做的转换和修改。 什么是好产品，什么是好的/坏的。

Answer 1

快速而脏，使用JDK附带的javap 。

 javap -c test Compiled from "test.java" public class test extends java.lang.Object{ public test(); Code: 0: aload_0 1: invokespecial #1; //Method java/lang/Object."":()V 4: return public static void main(java.lang.String[]) throws java.lang.Exception; Code: 0: ldc #2; //String CR_ABC_DEF_GHI 2: astore_1 3: ldc #3; //String TYPE=Eligibility Only|CLIENT_ID=62|EMPLOYER_ID=0|LOCATION_ID=0|PLAN_ID=all|FREQUENCY=52|FILE=null|FILETYPE=C|PROCESSTOLAUNCH=10|PROCESSTOLAUNCHSTATUS=100|SCHEDULE_ID=29837d692f4c43e786f1097fab7c360c 5: astore_2 6: ldc #4; //String \| 8: astore_3 9: ldc #5; //String FILE_NAME_TEMPLATE 11: astore 4 13: ldc #6; //String FILE 15: astore 5 17: new #7; //class java/lang/StringBuilder 20: dup 21: invokespecial #8; //Method java/lang/StringBuilder."":()V 24: aload_3 25: invokevirtual #9; //Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder; 28: aload 4 30: invokevirtual #9; //Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder; 33: ldc #10; //String = 35: invokevirtual #9; //Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder; 38: ldc #11; //String [^ 40: invokevirtual #9; //Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder; 43: aload_3 44: invokevirtual #9; //Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder; 47: ldc #12; //String ]* 49: invokevirtual #9; //Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder; 52: aload_3 53: invokevirtual #9; //Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder; 56: invokevirtual #13; //Method java/lang/StringBuilder.toString:()Ljava/lang/String; 59: astore 6 61: new #7; //class java/lang/StringBuilder 64: dup 65: invokespecial #8; //Method java/lang/StringBuilder."":()V 68: aload_3 69: invokevirtual #9; //Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder; 72: aload 5 74: invokevirtual #9; //Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder; 77: ldc #10; //String = 79: invokevirtual #9; //Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder; 82: ldc #11; //String [^ 84: invokevirtual #9; //Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder; 87: aload_3 88: invokevirtual #9; //Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder; 91: ldc #12; //String ]* 93: invokevirtual #9; //Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder; 96: aload_3 97: invokevirtual #9; //Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder; 100: invokevirtual #13; //Method java/lang/StringBuilder.toString:()Ljava/lang/String; 103: astore 7 105: new #7; //class java/lang/StringBuilder 108: dup 109: invokespecial #8; //Method java/lang/StringBuilder."":()V 112: aload_3 113: invokevirtual #9; //Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder; 116: aload 4 118: invokevirtual #9; //Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder; 121: ldc #10; //String = 123: invokevirtual #9; //Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder; 126: aload_1 127: invokevirtual #9; //Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder; 130: aload_3 131: invokevirtual #9; //Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder; 134: invokevirtual #13; //Method java/lang/StringBuilder.toString:()Ljava/lang/String; 137: astore 8 139: aload_2 140: aload 6 142: aload 8 144: invokevirtual #14; //Method java/lang/String.replaceAll:(Ljava/lang/String;Ljava/lang/String;)Ljava/lang/String; 147: aload 7 149: aload 8 151: invokevirtual #14; //Method java/lang/String.replaceAll:(Ljava/lang/String;Ljava/lang/String;)Ljava/lang/String; 154: astore 9 156: getstatic #15; //Field java/lang/System.out:Ljava/io/PrintStream; 159: new #7; //class java/lang/StringBuilder 162: dup 163: invokespecial #8; //Method java/lang/StringBuilder."":()V 166: ldc #16; //String before = 168: invokevirtual #9; //Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder; 171: aload_2 172: invokevirtual #9; //Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder; 175: invokevirtual #13; //Method java/lang/StringBuilder.toString:()Ljava/lang/String; 178: invokevirtual #17; //Method java/io/PrintStream.println:(Ljava/lang/String;)V 181: getstatic #15; //Field java/lang/System.out:Ljava/io/PrintStream; 184: new #7; //class java/lang/StringBuilder 187: dup 188: invokespecial #8; //Method java/lang/StringBuilder."":()V 191: ldc #18; //String pattern1 = 193: invokevirtual #9; //Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder; 196: aload 6 198: invokevirtual #9; //Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder; 201: invokevirtual #13; //Method java/lang/StringBuilder.toString:()Ljava/lang/String; 204: invokevirtual #17; //Method java/io/PrintStream.println:(Ljava/lang/String;)V 207: getstatic #15; //Field java/lang/System.out:Ljava/io/PrintStream; 210: new #7; //class java/lang/StringBuilder 213: dup 214: invokespecial #8; //Method java/lang/StringBuilder."":()V 217: ldc #19; //String pattern2 = 219: invokevirtual #9; //Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder; 222: aload 7 224: invokevirtual #9; //Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder; 227: invokevirtual #13; //Method java/lang/StringBuilder.toString:()Ljava/lang/String; 230: invokevirtual #17; //Method java/io/PrintStream.println:(Ljava/lang/String;)V 233: getstatic #15; //Field java/lang/System.out:Ljava/io/PrintStream; 236: new #7; //class java/lang/StringBuilder 239: dup 240: invokespecial #8; //Method java/lang/StringBuilder."":()V 243: ldc #20; //String replace = 245: invokevirtual #9; //Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder; 248: aload 8 250: invokevirtual #9; //Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder; 253: invokevirtual #13; //Method java/lang/StringBuilder.toString:()Ljava/lang/String; 256: invokevirtual #17; //Method java/io/PrintStream.println:(Ljava/lang/String;)V 259: getstatic #15; //Field java/lang/System.out:Ljava/io/PrintStream; 262: new #7; //class java/lang/StringBuilder 265: dup 266: invokespecial #8; //Method java/lang/StringBuilder."":()V 269: ldc #21; //String after = 271: invokevirtual #9; //Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder; 274: aload 9 276: invokevirtual #9; //Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder; 279: invokevirtual #13; //Method java/lang/StringBuilder.toString:()Ljava/lang/String; 282: invokevirtual #17; //Method java/io/PrintStream.println:(Ljava/lang/String;)V 285: return } 

Answer 2

最好的一个可能是jad：

http://www.varaneckas.com/jad

如果您使用Eclipse，则可以使用JadClipse插件，以获得更符合人体工程学的界面：

http://jadclipse.sourceforge.net/wiki/index.php/Main_Page

Answer 3

我发现这个工具非常好。

Answer 4

另一个java反编译器–AndroChef Java Decompiler可用： http ： //www.neshkov.com/ac_decompiler.html

Answer 5

我使用过JAD，可以测试它的实用性。

虽然任何解编译的代码最有可能没有任何注释，但如果代码被混淆，那么反编译将不会真正让你在任何地方。 它仍然看起来像胡言乱语。