Java Language
Desmontaje y Descompilación.
Buscar..
Sintaxis
- javap [opciones] <clases>
Parámetros
| Nombre | Descripción |
|---|---|
<classes> | Lista de clases para desmontar. Puede estar en el formato package1.package2.Classname , o package1/package2/Classname . No incluya el .class extensión. |
-help , --help , -? | Imprimir este mensaje de uso |
-version | Información de versión |
-v , -verbose | Imprimir información adicional |
-l | Imprimir número de línea y tablas de variables locales |
-public | Mostrar solo clases públicas y miembros |
-protected | Mostrar clases protegidas / públicas y miembros |
-package | Mostrar paquete / clases protegidas / públicas y miembros (predeterminado) |
-p , -private | Mostrar todas las clases y miembros |
-c | Desmontar el codigo |
-s | Imprimir firmas de tipo interno |
-sysinfo | Mostrar información del sistema (ruta, tamaño, fecha, hash MD5) de la clase en proceso |
-constants | Mostrar constantes finales |
-classpath <path> | Especifique dónde encontrar los archivos de clase de usuario |
-cp <path> | Especifique dónde encontrar los archivos de clase de usuario |
-bootclasspath <path> | Anular la ubicación de los archivos de clase de arranque |
Viendo bytecode con javap
Si desea ver el código de bytes generado para un programa Java, puede usar el comando javap proporcionado para verlo.
Suponiendo que tenemos el siguiente archivo fuente de Java:
package com.stackoverflow.documentation;
import org.springframework.stereotype.Service;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
@Service
public class HelloWorldService {
public void sayHello() {
System.out.println("Hello, World!");
}
private Object[] pvtMethod(List<String> strings) {
return new Object[]{strings};
}
protected String tryCatchResources(String filename) throws IOException {
try (InputStream inputStream = getClass().getResourceAsStream(filename)) {
byte[] bytes = new byte[8192];
int read = inputStream.read(bytes);
return new String(bytes, 0, read);
} catch (IOException | RuntimeException e) {
e.printStackTrace();
throw e;
}
}
void stuff() {
System.out.println("stuff");
}
}
Después de compilar el archivo fuente, el uso más simple es:
cd <directory containing classes> (e.g. target/classes)
javap com/stackoverflow/documentation/SpringExample
Lo que produce la salida.
Compiled from "HelloWorldService.java"
public class com.stackoverflow.documentation.HelloWorldService {
public com.stackoverflow.documentation.HelloWorldService();
public void sayHello();
protected java.lang.String tryCatchResources(java.lang.String) throws java.io.IOException;
void stuff();
}
Esto enumera todos los métodos no privados en la clase, pero eso no es particularmente útil para la mayoría de los propósitos. El siguiente comando es mucho más útil:
javap -p -c -s -constants -l -v com/stackoverflow/documentation/HelloWorldService
Lo que produce la salida:
Classfile /Users/pivotal/IdeaProjects/stackoverflow-spring-docs/target/classes/com/stackoverflow/documentation/HelloWorldService.class
Last modified Jul 22, 2016; size 2167 bytes
MD5 checksum 6e33b5c292ead21701906353b7f06330
Compiled from "HelloWorldService.java"
public class com.stackoverflow.documentation.HelloWorldService
minor version: 0
major version: 51
flags: ACC_PUBLIC, ACC_SUPER
Constant pool:
#1 = Methodref #5.#60 // java/lang/Object."<init>":()V
#2 = Fieldref #61.#62 // java/lang/System.out:Ljava/io/PrintStream;
#3 = String #63 // Hello, World!
#4 = Methodref #64.#65 // java/io/PrintStream.println:(Ljava/lang/String;)V
#5 = Class #66 // java/lang/Object
#6 = Methodref #5.#67 // java/lang/Object.getClass:()Ljava/lang/Class;
#7 = Methodref #68.#69 // java/lang/Class.getResourceAsStream:(Ljava/lang/String;)Ljava/io/InputStream;
#8 = Methodref #70.#71 // java/io/InputStream.read:([B)I
#9 = Class #72 // java/lang/String
#10 = Methodref #9.#73 // java/lang/String."<init>":([BII)V
#11 = Methodref #70.#74 // java/io/InputStream.close:()V
#12 = Class #75 // java/lang/Throwable
#13 = Methodref #12.#76 // java/lang/Throwable.addSuppressed:(Ljava/lang/Throwable;)V
#14 = Class #77 // java/io/IOException
#15 = Class #78 // java/lang/RuntimeException
#16 = Methodref #79.#80 // java/lang/Exception.printStackTrace:()V
#17 = String #55 // stuff
#18 = Class #81 // com/stackoverflow/documentation/HelloWorldService
#19 = Utf8 <init>
#20 = Utf8 ()V
#21 = Utf8 Code
#22 = Utf8 LineNumberTable
#23 = Utf8 LocalVariableTable
#24 = Utf8 this
#25 = Utf8 Lcom/stackoverflow/documentation/HelloWorldService;
#26 = Utf8 sayHello
#27 = Utf8 pvtMethod
#28 = Utf8 (Ljava/util/List;)[Ljava/lang/Object;
#29 = Utf8 strings
#30 = Utf8 Ljava/util/List;
#31 = Utf8 LocalVariableTypeTable
#32 = Utf8 Ljava/util/List<Ljava/lang/String;>;
#33 = Utf8 Signature
#34 = Utf8 (Ljava/util/List<Ljava/lang/String;>;)[Ljava/lang/Object;
#35 = Utf8 tryCatchResources
#36 = Utf8 (Ljava/lang/String;)Ljava/lang/String;
#37 = Utf8 bytes
#38 = Utf8 [B
#39 = Utf8 read
#40 = Utf8 I
#41 = Utf8 inputStream
#42 = Utf8 Ljava/io/InputStream;
#43 = Utf8 e
#44 = Utf8 Ljava/lang/Exception;
#45 = Utf8 filename
#46 = Utf8 Ljava/lang/String;
#47 = Utf8 StackMapTable
#48 = Class #81 // com/stackoverflow/documentation/HelloWorldService
#49 = Class #72 // java/lang/String
#50 = Class #82 // java/io/InputStream
#51 = Class #75 // java/lang/Throwable
#52 = Class #38 // "[B"
#53 = Class #83 // java/lang/Exception
#54 = Utf8 Exceptions
#55 = Utf8 stuff
#56 = Utf8 SourceFile
#57 = Utf8 HelloWorldService.java
#58 = Utf8 RuntimeVisibleAnnotations
#59 = Utf8 Lorg/springframework/stereotype/Service;
#60 = NameAndType #19:#20 // "<init>":()V
#61 = Class #84 // java/lang/System
#62 = NameAndType #85:#86 // out:Ljava/io/PrintStream;
#63 = Utf8 Hello, World!
#64 = Class #87 // java/io/PrintStream
#65 = NameAndType #88:#89 // println:(Ljava/lang/String;)V
#66 = Utf8 java/lang/Object
#67 = NameAndType #90:#91 // getClass:()Ljava/lang/Class;
#68 = Class #92 // java/lang/Class
#69 = NameAndType #93:#94 // getResourceAsStream:(Ljava/lang/String;)Ljava/io/InputStream;
#70 = Class #82 // java/io/InputStream
#71 = NameAndType #39:#95 // read:([B)I
#72 = Utf8 java/lang/String
#73 = NameAndType #19:#96 // "<init>":([BII)V
#74 = NameAndType #97:#20 // close:()V
#75 = Utf8 java/lang/Throwable
#76 = NameAndType #98:#99 // addSuppressed:(Ljava/lang/Throwable;)V
#77 = Utf8 java/io/IOException
#78 = Utf8 java/lang/RuntimeException
#79 = Class #83 // java/lang/Exception
#80 = NameAndType #100:#20 // printStackTrace:()V
#81 = Utf8 com/stackoverflow/documentation/HelloWorldService
#82 = Utf8 java/io/InputStream
#83 = Utf8 java/lang/Exception
#84 = Utf8 java/lang/System
#85 = Utf8 out
#86 = Utf8 Ljava/io/PrintStream;
#87 = Utf8 java/io/PrintStream
#88 = Utf8 println
#89 = Utf8 (Ljava/lang/String;)V
#90 = Utf8 getClass
#91 = Utf8 ()Ljava/lang/Class;
#92 = Utf8 java/lang/Class
#93 = Utf8 getResourceAsStream
#94 = Utf8 (Ljava/lang/String;)Ljava/io/InputStream;
#95 = Utf8 ([B)I
#96 = Utf8 ([BII)V
#97 = Utf8 close
#98 = Utf8 addSuppressed
#99 = Utf8 (Ljava/lang/Throwable;)V
#100 = Utf8 printStackTrace
{
public com.stackoverflow.documentation.HelloWorldService();
descriptor: ()V
flags: ACC_PUBLIC
Code:
stack=1, locals=1, args_size=1
0: aload_0
1: invokespecial #1 // Method java/lang/Object."<init>":()V
4: return
LineNumberTable:
line 10: 0
LocalVariableTable:
Start Length Slot Name Signature
0 5 0 this Lcom/stackoverflow/documentation/HelloWorldService;
public void sayHello();
descriptor: ()V
flags: ACC_PUBLIC
Code:
stack=2, locals=1, args_size=1
0: getstatic #2 // Field java/lang/System.out:Ljava/io/PrintStream;
3: ldc #3 // String Hello, World!
5: invokevirtual #4 // Method java/io/PrintStream.println:(Ljava/lang/String;)V
8: return
LineNumberTable:
line 13: 0
line 14: 8
LocalVariableTable:
Start Length Slot Name Signature
0 9 0 this Lcom/stackoverflow/documentation/HelloWorldService;
private java.lang.Object[] pvtMethod(java.util.List<java.lang.String>);
descriptor: (Ljava/util/List;)[Ljava/lang/Object;
flags: ACC_PRIVATE
Code:
stack=4, locals=2, args_size=2
0: iconst_1
1: anewarray #5 // class java/lang/Object
4: dup
5: iconst_0
6: aload_1
7: aastore
8: areturn
LineNumberTable:
line 17: 0
LocalVariableTable:
Start Length Slot Name Signature
0 9 0 this Lcom/stackoverflow/documentation/HelloWorldService;
0 9 1 strings Ljava/util/List;
LocalVariableTypeTable:
Start Length Slot Name Signature
0 9 1 strings Ljava/util/List<Ljava/lang/String;>;
Signature: #34 // (Ljava/util/List<Ljava/lang/String;>;)[Ljava/lang/Object;
protected java.lang.String tryCatchResources(java.lang.String) throws java.io.IOException;
descriptor: (Ljava/lang/String;)Ljava/lang/String;
flags: ACC_PROTECTED
Code:
stack=5, locals=10, args_size=2
0: aload_0
1: invokevirtual #6 // Method java/lang/Object.getClass:()Ljava/lang/Class;
4: aload_1
5: invokevirtual #7 // Method java/lang/Class.getResourceAsStream:(Ljava/lang/String;)Ljava/io/InputStream;
8: astore_2
9: aconst_null
10: astore_3
11: sipush 8192
14: newarray byte
16: astore 4
18: aload_2
19: aload 4
21: invokevirtual #8 // Method java/io/InputStream.read:([B)I
24: istore 5
26: new #9 // class java/lang/String
29: dup
30: aload 4
32: iconst_0
33: iload 5
35: invokespecial #10 // Method java/lang/String."<init>":([BII)V
38: astore 6
40: aload_2
41: ifnull 70
44: aload_3
45: ifnull 66
48: aload_2
49: invokevirtual #11 // Method java/io/InputStream.close:()V
52: goto 70
55: astore 7
57: aload_3
58: aload 7
60: invokevirtual #13 // Method java/lang/Throwable.addSuppressed:(Ljava/lang/Throwable;)V
63: goto 70
66: aload_2
67: invokevirtual #11 // Method java/io/InputStream.close:()V
70: aload 6
72: areturn
73: astore 4
75: aload 4
77: astore_3
78: aload 4
80: athrow
81: astore 8
83: aload_2
84: ifnull 113
87: aload_3
88: ifnull 109
91: aload_2
92: invokevirtual #11 // Method java/io/InputStream.close:()V
95: goto 113
98: astore 9
100: aload_3
101: aload 9
103: invokevirtual #13 // Method java/lang/Throwable.addSuppressed:(Ljava/lang/Throwable;)V
106: goto 113
109: aload_2
110: invokevirtual #11 // Method java/io/InputStream.close:()V
113: aload 8
115: athrow
116: astore_2
117: aload_2
118: invokevirtual #16 // Method java/lang/Exception.printStackTrace:()V
121: aload_2
122: athrow
Exception table:
from to target type
48 52 55 Class java/lang/Throwable
11 40 73 Class java/lang/Throwable
11 40 81 any
91 95 98 Class java/lang/Throwable
73 83 81 any
0 70 116 Class java/io/IOException
0 70 116 Class java/lang/RuntimeException
73 116 116 Class java/io/IOException
73 116 116 Class java/lang/RuntimeException
LineNumberTable:
line 21: 0
line 22: 11
line 23: 18
line 24: 26
line 25: 40
line 21: 73
line 25: 81
line 26: 117
line 27: 121
LocalVariableTable:
Start Length Slot Name Signature
18 55 4 bytes [B
26 47 5 read I
9 107 2 inputStream Ljava/io/InputStream;
117 6 2 e Ljava/lang/Exception;
0 123 0 this Lcom/stackoverflow/documentation/HelloWorldService;
0 123 1 filename Ljava/lang/String;
StackMapTable: number_of_entries = 9
frame_type = 255 /* full_frame */
offset_delta = 55
locals = [ class com/stackoverflow/documentation/HelloWorldService, class java/lang/String, class java/io/InputStream, class java/lang/Throwable, class "[B", int, class java/lang/String ]
stack = [ class java/lang/Throwable ]
frame_type = 10 /* same */
frame_type = 3 /* same */
frame_type = 255 /* full_frame */
offset_delta = 2
locals = [ class com/stackoverflow/documentation/HelloWorldService, class java/lang/String, class java/io/InputStream, class java/lang/Throwable ]
stack = [ class java/lang/Throwable ]
frame_type = 71 /* same_locals_1_stack_item */
stack = [ class java/lang/Throwable ]
frame_type = 255 /* full_frame */
offset_delta = 16
locals = [ class com/stackoverflow/documentation/HelloWorldService, class java/lang/String, class java/io/InputStream, class java/lang/Throwable, top, top, top, top, class java/lang/Throwable ]
stack = [ class java/lang/Throwable ]
frame_type = 10 /* same */
frame_type = 3 /* same */
frame_type = 255 /* full_frame */
offset_delta = 2
locals = [ class com/stackoverflow/documentation/HelloWorldService, class java/lang/String ]
stack = [ class java/lang/Exception ]
Exceptions:
throws java.io.IOException
void stuff();
descriptor: ()V
flags:
Code:
stack=2, locals=1, args_size=1
0: getstatic #2 // Field java/lang/System.out:Ljava/io/PrintStream;
3: ldc #17 // String stuff
5: invokevirtual #4 // Method java/io/PrintStream.println:(Ljava/lang/String;)V
8: return
LineNumberTable:
line 32: 0
line 33: 8
LocalVariableTable:
Start Length Slot Name Signature
0 9 0 this Lcom/stackoverflow/documentation/HelloWorldService;
}
SourceFile: "HelloWorldService.java"
RuntimeVisibleAnnotations:
0: #59()
Modified text is an extract of the original Stack Overflow Documentation
Licenciado bajo CC BY-SA 3.0
No afiliado a Stack Overflow