Question

Is there a way to compute a Java class s method s signature? A signature
like ([Ljava/lang/String;)V represents a function that takes a String[] as argument
and returns void.

What s the rule to compute the signature?

Answer 1

它总是带有一套括号的括号,其中一类是没有mas子或任何东西的,其次是封闭区之后的回报值的表示器。它非常直截了当。

Here’s a table of type signatures:

Signature    Java Type
Z    boolean
B    byte
C    char
S    short
I    int
J    long
F    float
D    double
V    void
L fully-qualified-class ;    fully-qualified-class
[ type   type[]

Those last two mean that to name a class, you say, for example, Ljava/lang/Object;, and to name an array of (for example) int, you say [I, and an array of array of int is [[I.

如果您想字面上compute signature的签名依据反省,其范围足够简单;只是使用上表,并附有处理物体和阵列的规则。

Answer 2

Justpr javap -s <class-name> in the rafter contained the .class file. 它将以100%的准确性告诉你。无需对这些事情进行猜测。

Answer 3

快速搜索发现这一网页:

http://www.rgagnon.com/javadetails/java-0286.html。

There are two parts to the signature. The first part is enclosed within the parentheses and represents the method s arguments. The second portion follows the closing parenthesis and represents the return type. The mapping between the Java type and C type is
Type     Chararacter 
boolean      Z 
byte         B 
char         C 
double       D 
float        F 
int          I 
long         J 
object       L 
short        S 
void         V 
array        [ 

Answer 4

See here for some details.

从根本上说,它会给人带来一些好处,然后是回报。

Answer 5

http://java.sun.com/docs/books/jls/second_edition/html/classes.doc.html#38649”rel=“nofollow” §8.4.2:

8.4.2 Method Signature

The signature of a method consists of the name of the method and the number and types of formal parameters to the method. A class may not declare two methods with the same signature, or a compile-time error occurs.

The example:
class Point implements Move {
  int x, y;
  abstract void move(int dx, int dy);
  void move(int dx, int dy) { x += dx; y += dy; }
}
causes a compile-time error because it declares two move methods with the same signature. This is an error even though one of the declarations is abstract.

因此,“规则”是

http://www.ohchr.org。

Answer 6

http://java.sun.com/docs/books/jvms/second_edition/html/ClassFile.doc.html#7035“rel=“nofollow” Java 虚拟机器规格

Answer 7

是否有办法计算 Java类的签名方法?

您可以通过使用 apache Commons-bcel ,从方案上做到这一点。

package com.mageddo.coc.classes;

import java.io.IOException;

import com.sun.org.apache.bcel.internal.classfile.ClassParser;

public class JavaClass {

  public static String structureAsText(Class<?> clazz) throws IOException {

    final String classPath =
        String.format(
            "/%s.class",
            clazz.getName()
                .replace( . ,  / )
        );

    final ClassParser classParser = new ClassParser(
        JavaClass.class.getResourceAsStream(classPath),
        clazz.getSimpleName() + ".java"
    );

    
    return classParser.parse()
        .toString();
  }

  public static void main(String[] args) throws IOException {
    System.out.println(JavaClass.structureAsText(JavaClass.class));
  }

}

产出

public class com.mageddo.coc.classes.JavaClass extends java.lang.Object
filename        JavaClass.java
compiled from       JavaClass.java
compiler version    52.0
access flags        33
constant pool       98 entries
ACC_SUPER flag      true

Attribute(s):
    SourceFile: JavaClass.java

3 methods:
    public void <init>()
    public static String structureAsText(Class clazz) [Signature: (Ljava/lang/Class<*>;)Ljava/lang/String;]
        throws Exceptions: java.io.IOException
    public static void main(String[] args)
        throws Exceptions: java.io.IOException

8.4.2 Method Signature

友情链接