String类总结 - 黑马程序员技术交流社区

package com.xlunaer.alan;
public class StringTest {
public static void main(String[] args) {
// TODO Auto-generated method stub
String s = " abc defg hijkl mnopq rstuvw xyz &&& hello java 1234567";
//获取
char s1 = s.charAt(1);
int s2 = s.codePointAt(1);
int length = s.length();
int s3 = s.indexOf(98);
int s4 =s.indexOf("mn", 0);
int s5 = s.lastIndexOf("a");
System.out.println(s1 + "\t" + s2 + "\t" + length + "\t" + s3 + "\t" + s4 + "\t" + s5);
//判断
out(s.contains("abc"));
out(s.isEmpty());
out(s.equals("abc defg hijkl mnopq rstuvw xyz &&& hello java 1234567"));
out(s.contentEquals("abc defg hijkl mnopq rstuvw xyz &&& hello java 1234567"));
out(s.endsWith("567"));
out(s.startsWith("abc de"));
//转换
out(s.toUpperCase());
out(s.toUpperCase().toLowerCase());
out(new String(new char[] {'a', 'b', 'c'}));
char[] c = new char[] {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'};
String s6 =new String(c, 1, 5);
out(s6);
out(String.valueOf(c));
//替换
out(s.replace('a', 'c'));
out(s.replace("a", "java"));
//分割
String[] ss = s.split(" ");
for(String v: ss) {
out(v);
}
//子串
out(s.subSequence(1, 3));
//去除空格
out(s.trim());
//比较
//相等返回 0 ；在字典上比源字符串大返回一个整数；反之返回一个负数
out(s.compareToIgnoreCase(" ABC DEFG HIJKL MNOPQ RSTUVW XYZ &&& HELLO JAVA 1234567"));
out(noneSpace(s));
}
public static void out(Object obj) {
System.out.println(obj);
}
public static String noneSpace(String s) {
char[] c2 = s.toCharArray();
String s2 = "";
for(char c: c2) {
if(c != ' ') {
s2 += c;
}
}
return s2;
}
}

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