关于java字符串String以及Hashcode的一些整理
hashcode即是对象地址的十进制形式，而equals方法即是在比较两个对象的hashcode是否相等
package com.test.wx.testequals;public class TestEquals { public static void testEquals() { String a = "a"; String b = "a"; boolean result = a.equals(b); System.out.PRintln(result); // true System.out.println(a.hashCode() == b.hashCode()); // true } public static void testEqual() { String a = "a"; String b = "a"; if(a == b) { // true System.out.println("true"); System.out.println(a.hashCode() == b.hashCode()); }else { System.out.println("false"); } } public static void testEquals2() { String a = "a"; String b = a; // equals方法比较两个对象的hashcode,hashcode即对象的地址 System.out.println(a.equals(b)); // == 比较两个变量或者对象的值是否相等，equals比较两个对象的引用是否相等（是否指向同一个对象） System.out.println(a==b); } public static void normalTest() { int a = 12; String b = String.valueOf(a); } public static void testObjectHashcode() { User user1 = new User(1, "test"); User user2 = new User(2, "test"); System.out.println("user1 toString: "+user1); System.out.println("user1 hashcode: "+user1.hashCode()); // hashcode即是对象地址的十进制形式 System.out.println(Integer.valueOf("659e0bfd", 16)); System.out.println(user2); } public static void hexToDeciaml() { long a = 1021653256; System.out.println(Long.toHexString(a)); //3ce53108 System.out.println(Integer.valueOf("659e0bfd", 16)); } public static void main(String[] args) {// testEquals();// testEqual();// testEquals2();// hexToDeciaml(); testObjectHashcode(); }}枚举enum整理
枚举enum是一种类型，不是类，所以不能被实例化，一般用来定义集合常量
package com.test.wx.testenum;public class EnumTest { PrinterType printType; enum PrinterType { INKJET, DOTMATRIX, LASER }; public EnumTest(PrinterType pType) { printType = pType; } public static void main(String[] args) {// PrinterType pType = new PrinterType(); EnumTest enumTest = new EnumTest(PrinterType.LASER); System.out.println(enumTest.printType); }}新闻热点
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