JVM学习-javap解析Class文件
C:\Users\Administrator\IdeaProjects\jvm\target\classes\com\chapter09>javap -version JavapTest.class
1.8.0_131
Compiled from "JavapTest.java"
public class com.chapter09.JavapTest {
boolean flag;
protected char gender;
public java.lang.String info;
public static final int COUNTS;
public com.chapter09.JavapTest();
int getNum(int);
protected char showGender();
public void showInfo();
static {};
}
// -public 显示公共信息
C:\Users\Administrator\IdeaProjects\jvm\target\classes\com\chapter09>javap -public JavapTest.class
Compiled from "JavapTest.java"
public class com.chapter09.JavapTest {
public java.lang.String info;
public static final int COUNTS;
public com.chapter09.JavapTest();
public void showInfo();
}
// -protected
C:\Users\Administrator\IdeaProjects\jvm\target\classes\com\chapter09>javap -protected JavapTest.class
Compiled from "JavapTest.java"
public class com.chapter09.JavapTest {
protected char gender;
public java.lang.String info;
public static final int COUNTS;
public com.chapter09.JavapTest();
protected char showGender();
public void showInfo();
}
// -private || -p 大于或等于private权限
C:\Users\Administrator\IdeaProjects\jvm\target\classes\com\chapter09>javap -private JavapTest.class
Compiled from "JavapTest.java"
public class com.chapter09.JavapTest {
private int num;
boolean flag;
protected char gender;
public java.lang.String info;
public static final int COUNTS;
public com.chapter09.JavapTest();
private com.chapter09.JavapTest(boolean);
private void methodPrivate();
int getNum(int);
protected char showGender();
public void showInfo();
static {};
}
// -package 显示非私有的信息
C:\Users\Administrator\IdeaProjects\jvm\target\classes\com\chapter09>javap -package JavapTest.class
Compiled from "JavapTest.java"
public class com.chapter09.JavapTest {
boolean flag;
protected char gender;
public java.lang.String info;
public static final int COUNTS;
public com.chapter09.JavapTest();
int getNum(int);
protected char showGender();
public void showInfo();
static {};
}
// -sysinfo
C:\Users\Administrator\IdeaProjects\jvm\target\classes\com\chapter09>javap -sysinfo JavapTest.class
Classfile /C:/Users/Administrator/IdeaProjects/jvm/target/classes/com/chapter09/JavapTest.class //字节码文件路径
Last modified 2024-5-27; size 1348 bytes //日期
MD5 checksum 85dc41e7e2e7128d8899b5d131d7975f //MD5散列
Compiled from "JavapTest.java"
public class com.chapter09.JavapTest {
boolean flag;
protected char gender;
public java.lang.String info;
public static final int COUNTS;
public com.chapter09.JavapTest();
int getNum(int);
protected char showGender();
public void showInfo();
static {};
}
// -constants
C:\Users\Administrator\IdeaProjects\jvm\target\classes\com\chapter09>javap -constants JavapTest.class
Compiled from "JavapTest.java"
public class com.chapter09.JavapTest {
boolean flag;
protected char gender;
public java.lang.String info;
public static final int COUNTS = 1;
public com.chapter09.JavapTest();
int getNum(int);
protected char showGender();
public void showInfo();
static {};
}
// -s 输出内部类型签名
C:\Users\Administrator\IdeaProjects\jvm\target\classes\com\chapter09>javap -s JavapTest.class
Compiled from "JavapTest.java"
public class com.chapter09.JavapTest {
boolean flag;
descriptor: Z
protected char gender;
descriptor: C
public java.lang.String info;
descriptor: Ljava/lang/String;
public static final int COUNTS;
descriptor: I
public com.chapter09.JavapTest();
descriptor: ()V
int getNum(int);
descriptor: (I)I
protected char showGender();
descriptor: ()C
public void showInfo();
descriptor: ()V
static {};
descriptor: ()V
}
// -l 输出行号和本地变量表
C:\Users\Administrator\IdeaProjects\jvm\target\classes\com\chapter09>javap -l JavapTest.class
Compiled from "JavapTest.java"
public class com.chapter09.JavapTest {
boolean flag;
protected char gender;
public java.lang.String info;
public static final int COUNTS;
public com.chapter09.JavapTest();
LineNumberTable:
line 20: 0
line 18: 4
line 20: 10
LocalVariableTable:
Start Length Slot Name Signature
0 11 0 this Lcom/chapter09/JavapTest;
int getNum(int);
LineNumberTable:
line 26: 0
LocalVariableTable:
Start Length Slot Name Signature
0 7 0 this Lcom/chapter09/JavapTest;
0 7 1 i I
protected char showGender();
LineNumberTable:
line 29: 0
LocalVariableTable:
Start Length Slot Name Signature
0 5 0 this Lcom/chapter09/JavapTest;
public void showInfo();
LineNumberTable:
line 32: 0
line 33: 3
line 34: 30
LocalVariableTable:
Start Length Slot Name Signature
0 31 0 this Lcom/chapter09/JavapTest;
3 28 1 i I
static {};
LineNumberTable:
line 15: 0
line 16: 3
LocalVariableTable:
Start Length Slot Name Signature
}
// -c 对代码进行反编译
C:\Users\Administrator\IdeaProjects\jvm\target\classes\com\chapter09>javap -l JavapTest.class
Compiled from "JavapTest.java"
public class com.chapter09.JavapTest {
boolean flag;
protected char gender;
public java.lang.String info;
public static final int COUNTS;
public com.chapter09.JavapTest();
LineNumberTable:
line 20: 0
line 18: 4
line 20: 10
LocalVariableTable:
Start Length Slot Name Signature
0 11 0 this Lcom/chapter09/JavapTest;
int getNum(int);
LineNumberTable:
line 26: 0
LocalVariableTable:
Start Length Slot Name Signature
0 7 0 this Lcom/chapter09/JavapTest;
0 7 1 i I
protected char showGender();
LineNumberTable:
line 29: 0
LocalVariableTable:
Start Length Slot Name Signature
0 5 0 this Lcom/chapter09/JavapTest;
public void showInfo();
LineNumberTable:
line 32: 0
line 33: 3
line 34: 30
LocalVariableTable:
Start Length Slot Name Signature
0 31 0 this Lcom/chapter09/JavapTest;
3 28 1 i I
static {};
LineNumberTable:
line 15: 0
line 16: 3
LocalVariableTable:
Start Length Slot Name Signature
}
C:\Users\Administrator\IdeaProjects\jvm\target\classes\com\chapter09>javap -c JavapTest.class
Compiled from "JavapTest.java"
public class com.chapter09.JavapTest {
boolean flag;
protected char gender;
public java.lang.String info;
public static final int COUNTS;
public com.chapter09.JavapTest();
Code:
0: aload_0
1: invokespecial #1 // Method java/lang/Object."<init>":()V
4: aload_0
5: ldc #2 // String java
7: putfield #3 // Field info:Ljava/lang/String;
10: return
int getNum(int);
Code:
0: aload_0
1: getfield #5 // Field num:I
4: iload_1
5: iadd
6: ireturn
protected char showGender();
Code:
0: aload_0
1: getfield #6 // Field gender:C
4: ireturn
public void showInfo();
Code:
0: bipush 10
2: istore_1
3: getstatic #7 // Field java/lang/System.out:Ljava/io/PrintStream;
6: new #8 // class java/lang/StringBuilder
9: dup
10: invokespecial #9 // Method java/lang/StringBuilder."<init>":()V
13: aload_0
14: getfield #3 // Field info:Ljava/lang/String;
17: invokevirtual #10 // Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
20: iload_1
21: invokevirtual #11 // Method java/lang/StringBuilder.append:(I)Ljava/lang/StringBuilder;
24: invokevirtual #12 // Method java/lang/StringBuilder.toString:()Ljava/lang/String;
27: invokevirtual #13 // Method java/io/PrintStream.println:(Ljava/lang/String;)V
30: return
static {};
Code:
0: ldc #14 // String www.lotus.com
2: astore_0
3: return
}
// -v 显示最全的字节码反编译数据
C:\Users\Administrator\IdeaProjects\jvm\target\classes\com\chapter09>javap -v JavapTest.class
Classfile /C:/Users/Administrator/IdeaProjects/jvm/target/classes/com/chapter09/JavapTest.class //位置
Last modified 2024-5-27; size 1348 bytes //日期，大小
MD5 checksum 85dc41e7e2e7128d8899b5d131d7975f //MD5散列值
Compiled from "JavapTest.java"
public class com.chapter09.JavapTest
minor version: 0 //副版本号
major version: 52 //主版本号
flags: ACC_PUBLIC, ACC_SUPER //访问标识
Constant pool:
#1 = Methodref #16.#46 // java/lang/Object."<init>":()V
#2 = String #47 // java
#3 = Fieldref #15.#48 // com/chapter09/JavapTest.info:Ljava/lang/String;
#4 = Fieldref #15.#49 // com/chapter09/JavapTest.flag:Z
#5 = Fieldref #15.#50 // com/chapter09/JavapTest.num:I
#6 = Fieldref #15.#51 // com/chapter09/JavapTest.gender:C
#7 = Fieldref #52.#53 // java/lang/System.out:Ljava/io/PrintStream;
#8 = Class #54 // java/lang/StringBuilder
#9 = Methodref #8.#46 // java/lang/StringBuilder."<init>":()V
#10 = Methodref #8.#55 // java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
#11 = Methodref #8.#56 // java/lang/StringBuilder.append:(I)Ljava/lang/StringBuilder;
#12 = Methodref #8.#57 // java/lang/StringBuilder.toString:()Ljava/lang/String;
#13 = Methodref #58.#59 // java/io/PrintStream.println:(Ljava/lang/String;)V
#14 = String #60 // www.lotus.com
#15 = Class #61 // com/chapter09/JavapTest
#16 = Class #62 // java/lang/Object
#17 = Utf8 num
#18 = Utf8 I
#19 = Utf8 flag
#20 = Utf8 Z
#21 = Utf8 gender
#22 = Utf8 C
#23 = Utf8 info
#24 = Utf8 Ljava/lang/String;
#25 = Utf8 COUNTS
#26 = Utf8 ConstantValue
#27 = Integer 1
#28 = Utf8 <init>
#29 = Utf8 ()V
#30 = Utf8 Code
#31 = Utf8 LineNumberTable
#32 = Utf8 LocalVariableTable
#33 = Utf8 this
#34 = Utf8 Lcom/chapter09/JavapTest;
#35 = Utf8 (Z)V
#36 = Utf8 methodPrivate
#37 = Utf8 getNum
#38 = Utf8 (I)I
#39 = Utf8 i
#40 = Utf8 showGender
#41 = Utf8 ()C
#42 = Utf8 showInfo
#43 = Utf8 <clinit>
#44 = Utf8 SourceFile
#45 = Utf8 JavapTest.java
#46 = NameAndType #28:#29 // "<init>":()V
#47 = Utf8 java
#48 = NameAndType #23:#24 // info:Ljava/lang/String;
#49 = NameAndType #19:#20 // flag:Z
#50 = NameAndType #17:#18