java_API_常用字符串方法

String s="  abc  abc  abc     ";
System.out.println("1位置字符:"+s.charAt(1));
System.out.println("2位置字符:"+s.charAt(2));
System.out.println("变大写:"+s.toLowerCase());
System.out.println("长度:"+s.length());
System.out.println("比大小:"+s.compareTo("  xyz"));
System.out.println("前缀:"+s.startsWith(" abc"));
System.out.println("后缀:"+s.endsWith("abc"));
System.out.println("找bc起始位置:"+s.indexOf("bc"));
System.out.println("从4向后找bc:"+s.indexOf("bc",4));
System.out.println("最后一个bc:"+s.lastIndexOf("bc"));
System.out.println("找不存在的字符串:"+s.indexOf("xxxx"));
System.out.println("a替换成*:"+s.replace('a', '*'));
System.out.println("截取6到末尾:"+s.substring(6));
System.out.println("截取【6，10）:"+s.substring(6, 10));
System.out.println("去除两端空格:"+s.trim());