初学Java,做一个学习笔记,方便以后查找和温习。
package myjava;
public class Mystring {
public static void main(String args[]) {
String strOrig = "ken,Hello dog!Good job!Hello world!";
// 字符串查找[lastIndexOf:最后一次出现的位置,indexOf:第一次出现的位置]
// int lastIndex = strOrig.lastIndexOf("Hello");
int Index2 = strOrig.indexOf("Hello");
if (Index2 == -1) {
System.out.println("没有找到");
} else {
System.out.println("第一次出现的位置在" + Index2);
}
// 字符串截取
String newStr = strOrig.substring(4);
System.out.println(newStr);
// 字符串替换
System.out.println(newStr.replace("dog", "King"));
System.out.println(newStr.replaceAll("Hello", "Great"));
System.out.println(newStr.replaceFirst("Hello", "lalalal"));
// 字符串反转
String oldChar = "abcdef";
String newChar = new StringBuffer(oldChar).reverse().toString();
System.out.println("反转后的字符串为:" + newChar);
// 字符串分割
String deChar = "hava-a-good-time";
String[] deArr;
deArr = deChar.split("-");
for (String item : deArr) {
System.out.println("分割后的数组为:" + item);
}
// 字符串大小写转换
String bigStr = "JUST DO IT";
String smStr = bigStr.toLowerCase();
System.out.println("转换为小写:" + smStr);
String newBigStr = smStr.toUpperCase();
System.out.println("重新转换为大写:" + newBigStr);
// 判断两个字符串是否相等
String firstStr = "kens";
String secondStr = "kena";
boolean comResult = firstStr.regionMatches(0, secondStr, 0, 4);
System.out.println("比较结果为:" + comResult);
}
}