归纳：Java中常用方法

归纳：Java中常用方法

public class Test {
 
 public static void main(String[] args) {
  //String；类创建类型有两种
//  String name1 = "Tim";
//  
//  String name2 = "Tim";
//  
//  String name3 = new String("Tim");
//  
//  String name4 = new String("Tim");
//  
//  System.out.println(name1==name2);
//  System.out.println(name3==name4);
  
//  String name1 = "Tom";
//  
//  String name2 = "tom";
//  System.out.println(name1.length()); //得到字符串长度方法
//  
//  System.out.println(name1.startsWith("To")); //字符串以什么开头
//  System.out.println(name1.endsWith("om")); //字符串以什么结尾
//  System.out.println(name1.equals("Tom")); //字符串是否相等
//  System.out.println(name1.equals("Tim")); 
//  
//  System.out.println(name1.equalsIgnoreCase(name2)); //字符串忽略大小
  
  
  
  
//  String letters = "abcdefghijka";
//  
//  System.out.println(letters.indexOf("e")); //获取某个字符在原来字符串的位置，从0开始，从前往后
//  System.out.println(letters.indexOf("g"));
//  
//  System.out.println(letters.indexOf("fgh"));
//  
//  System.out.println(letters.lastIndexOf("a")); //获取某个字符在原来字符串的位置，从0开始，从后往前
//  
//  String sub = letters.substring(0);
//  System.out.println(sub);
//  
//  String sub1 = letters.substring(1);
//  System.out.println(sub1);
//  
//  String sub3 = letters.substring(0,3);
//  System.out.println(sub3);
//  
  
  
  int a = 12;
  int b = 12;
  System.out.println(12==12);
  System.out.println(a==b);
  
  Test t1 = new Test();
  Test t2 = new Test();
  System.out.println(t1==t2);
  
  String name1 = "Tom";
  String name2 = "Tom";
  Object obj = "Tom";
  System.out.println(name1.equals(obj));
  
  Test test  = new Test();
  obj = test;
  System.out.println(name1.equals(obj));
  
  String name3 = new String("Tom");
  obj = name3;
  System.out.println(name1.equals(obj));
  
  String name4 = new String("To");
  obj = name4;
  System.out.println(name1.equals(obj));
 
//   public boolean equals(Object anObject) {
//          if (this == anObject) {  //原来那个所处地址（nmae1）
//              return true;
//          }
//          if (anObject instanceof String) {
//              String anotherString = (String)anObject;
//              int n = value.length;
//              if (n == anotherString.value.length) {
//                  char v1[] = value;
//                  char v2[] = anotherString.value;
//                  int i = 0;
//                  while (n-- != 0) {
//                      if (v1[i] != v2[i])
//                          return false;
//                      i++;
//                  }
//                  return true;
//              }
//          }
//          return false;
//      }
  
  String name = " t o m ";
  System.out.println(name.length());
  System.out.println(name.trim().length());
  
  String names = "hetao#wangjianming,guohangyu";
  
  names = names.replaceAll("#",",");
  System.out.println(names);
  
  String [] ns = names.split(",");
  
  for(String n: ns) {
   System.out.println(n);
  }
  
  //课堂题目第一题
  String namess = "卡巴斯基#杀毒软件#俄罗斯#";
  namess = namess.replaceAll("#", ",");
  System.out.println(namess);
  
  String [] ad = namess.split(",");
  
  for(String as : ad) {
   System.out.println(as);
  }
  
  
  //2、现有如下学生参加学校运动会xt_0712 xt_0704 xt_0715 xt_0504 xt_0602 xt_0711 xt_0607，统计蓝桥7期（以xt_07开头的是兴唐7期）有多少人参加比赛。
  
//  String namesss = "xt_0712xt_0704xt_0715xt_0504xt_0602xt_0711xt_0607统计蓝桥7期";
//  for(int i =0; i<namesss.length();i+=7) {
//   if(String sub3 = letters.substring(0,3););
//   int number1=0;
//   number
//  }
  
  //根据身份证号判断生日和性别
  String ID = "511023199805038214";
  String birth = ID.substring(6, 14);
  System.out.println(birth);
  
  int sex = Integer.parseInt(ID.substring(16, 17));
  if(sex%2==0) {
   System.out.println("女");
   return;
  }
  System.out.println("男");
  
  
  
  String q ="tom";
  String w = new String("jim");
  
  String letter = "abf" + "red";
  
  String mingzi = "lucy";
  mingzi = mingzi + ",jim";
  mingzi = mingzi + ",kucy";
  System.out.println(mingzi); //浪费内存
  
  StringBuffer sb = new StringBuffer("lucy");
  sb.append(",jim");
  sb.append(",kucy");
  System.out.println(sb);
  
//  for(int j = 0;j<sb.length();j++) {
//   System.out.println(sb);
//  }
  
  String str = sb.toString();
  System.out.println(str);
 }
 
}