Name和CanonicalName有什么区别？

Question

Java的Class.getName()和Class.getCanonicalName()之间的区别是什么？

Answer 1

考虑下面的程序：

package org.test.stackoverflow; 

public class CanonicalName { 

    public static void main(String[] args) { 
    CanonicalName cn = new CanonicalName(); 
    cn.printClassNames(); 
    } 

    private Anonymous anony; 
    private MyAnony myAnony; 

    public CanonicalName() { 
    anony = new Anonymous() { 
     public void printInterface() { 
     System.out.println("Anony Name: " + getClass().getName()); 
     System.out.println("Anony CanonicalName: " + getClass().getCanonicalName()); 
     } 
    }; 
    myAnony = new MyAnony(); 
    } 

    public void printClassNames() { 
    System.out.println("CanonicalName, Name: " + getClass().getName()); 
    System.out.println("CanonicalName, CanonicalName: " + getClass().getCanonicalName()); 
    anony.printInterface(); 
    myAnony.printInterface(); 
    } 

    private static interface Anonymous { 
    public void printInterface(); 
    } 

    private static class MyAnony implements Anonymous { 
    public void printInterface() { 
     System.out.println("MyAnony Name: " + getClass().getName()); 
     System.out.println("MyAnony CanonicalName: " + getClass().getCanonicalName()); 
    } 
    } 
} 

输出：

CanonicalName, Name: org.test.stackoverflow.CanonicalName 
CanonicalName, CanonicalName: org.test.stackoverflow.CanonicalName 
Anony Name: org.test.stackoverflow.CanonicalName$1 
Anony CanonicalName: null 
MyAnony Name: org.test.stackoverflow.CanonicalName$MyAnony 
MyAnony CanonicalName: org.test.stackoverflow.CanonicalName.MyAnony 

如此看来，对于基础类，它们将返回同样的事情。对于内部类，getName()使用$命名约定（即什么是用于.class文件），并getCanonicalName()的回报，如果你试图将类实例，你会用什么。你不能用（匿名）匿名类来做到这一点，所以这就是为什么getCanonicalName()返回null。