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);
}
}