java.lang.String.hashCode() 方法返回该字符串的哈希码。对于String对象的哈希码的计算方法为：

s[0]*31^(n-1) + s[1]*31^(n-2) + ... + s[n-1] 其中，s[i]为字符串的第i个字符，n是字符串的长度，^表示求幂

声明

以下是java.lang.String.hashCode()方法的声明

public int hashCode()

参数

• NA

返回值

此方法返回该对象的哈希码值。

异常

• NA

例子

下面的例子显示java.lang.String.hashCode()方法的使用。

package com.yiibai;

import java.lang.*;

public class StringDemo {

  public static void main(String[] args) {
  
    Integer i = new Integer(50);
    Long l = new Long(50);
    Float f = new Float(50);
    Integer i2 = new Integer(0);
    
    // hash codes of different objects with same value are always same
    System.out.println("Hash code of " + i + " is =  " + i.hashCode());
    System.out.println("Hash code of " + l + " is =  " + l.hashCode());
  
    // hash code for float value i.e different from Integer and Long
    System.out.println("Hash code of " + f + " is =  " + f.hashCode());    
        
    // hash code value of number zero(0) is zero(0)
    System.out.println("Hash code of " + i2 + " is = " + i2.hashCode());

    String str = "this is yiibai";
    
    // hash code of string str
    System.out.println("Hash code of string is = " + str.hashCode());
  }
}

让我们编译并运行上述程序，这将产生以下结果：

Hash code of 50 is = 50
Hash code of 50 is = 50
Hash code of 50.0 is = 1112014848
Hash code of 0 is = 0
Hash code of string is = 643938959