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- package j2se;
-
- public class StringDemo {
- private String demoString="ceshixiaoyouning";
-
- public void testString(){
- String dsg=demoString.concat("very beautiful");//字符串相加,也可以用+来表示
- System.out.println(dsg);
-
- int len=demoString.length();//字符串的长度
- System.out.println(len);
-
- boolean eq="ceshixiaoyouning".equals(demoString);//比较两个字符串是否相等
- System.out.println(eq);
-
- String sub=demoString.substring(5, 8);//取子字符串,从第5个字符开始,到底8个字符,但是不包含第8个字符
- System.out.println(sub);
-
- String subString=demoString.substring(5);//取子字符串,从第5个字符开始一直到字符串尾
- System.out.println(subString);
-
- boolean sw =demoString.startsWith("ceshi");//判断是否以某个字符串开头
- System.out.println(sw);
-
- boolean ew=demoString.endsWith("youning");//判断石头以某个字符串结尾
- System.out.println(ew);
-
- int subIndex=demoString.indexOf("ce");//找出子字符串在字符串中第一次出现的index,如果找不到则返回-1
- System.out.println(subIndex);
-
- int lastIndex=demoString.lastIndexOf("i");//找出子字符串在字符串最后一次出现的index,如果找不到则返回-1
- System.out.println(lastIndex);
-
- System.out.println(demoString.toUpperCase());//字符串中的字全变成大写
- System.out.println(demoString.toLowerCase());//字符串中的字全变成小写
- System.out.println(" youning ".trim());//将字符串首尾的空格去掉
-
- String subReplace=demoString.replace("ceshi", "hello");//将字符串中的某段字符串替换成新的字符串
- System.out.println(subReplace);
-
- String subReplaceF=demoString.replaceFirst("i", "hhh");//将字符串中第一次出现的子字符串替换成新的字符串,支持正则
- System.out.println(subReplaceF);
-
- String subReplaceA=demoString.replaceAll("i", "hhh");//将字符串中出现的所有子字符串替换成新的子字符串,支持正则
- System.out.println(subReplaceA);
- }
-
- public static void main(String[] args) {
- StringDemo s=new StringDemo();
- s.testString();
- }
- }
复制代码 运行结果:
ceshixiaoyouningvery beautiful
16
true
xia
xiaoyouning
true
true
0
13
CESHIXIAOYOUNING
ceshixiaoyouning
youning
helloxiaoyouning
ceshhhhxiaoyouning
ceshhhhxhhhaoyounhhhng
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