public static void main(String[] args) {String str = "Hello";char[] chars = str.toCharArray();System.out.println("字符串转字符数组：");for (int i=0; i<chars.length; i++){System.out.print(chars[i]+" ");}System.out.println();System.out.println("字符数组转字符串：");String str1 = String.copyValueOf(chars);System.out.println(str1);System.out.println("字符串指定位置字符：");System.out.println(str.charAt(1));System.out.println("字符串转字节数组");byte[] bytes = str.getBytes();for (int i=0; i<bytes.length; i++){System.out.print(bytes[i]+" ");}System.out.println();System.out.println("字节数组转字符串：");System.out.println(new String(bytes));System.out.println("大小写转换：");System.out.println(str.toUpperCase());System.out.println(str.toLowerCase());System.out.println("字符串的比较：compareTo()");/** compareTo()的返回值是整型,* 它是先比较对应字符的大小(ASCII码顺序),* 如果第一个字符和参数的第一个字符不等,* 结束比较返回他们之间的差值,* 如果第一个字符和参数的第一个字符相等,* 则以第二个字符和参数的第二个字符做比较,* 以此类推,直至比较的字符或被比较的字符有一方全比较完,这时就比较字符的长度. * */String s1 = "abc"; String s2 = "abcd"; String s3 = "abcdfg"; String s4 = "1bcdfg"; String s5 = "cdfg"; String s6 = "Abc";System.out.println(s1.compareTo(s2)); // -1 (前面相等,s1长度小1) System.out.println(s1.compareTo(s3)); // -3 (前面相等,s1长度小3) System.out.println(s1.compareTo(s4)); // 48 ("a"的ASCII码是97,"1"的的ASCII码是49,所以返回48) System.out.println(s1.compareTo(s5)); // -2 ("a"的ASCII码是97,"c"的ASCII码是99,所以返回-2)System.out.println(s1.compareToIgnoreCase(s6)); // 0 忽略大小写/** str1.equals(str2)比较内容* str1==str2比较内存地址* */String s11 = new String("abc");System.out.println(s1.equals(s11)); //trueSystem.out.println(s1==s11); //falseString s12 = "abc";System.out.println(s1.equals(s12)); //trueSystem.out.println(s1==s12); //trueSystem.out.println("判断字符串前缀和后缀：");System.out.println(str.startsWith("He")); //trueSystem.out.println(str.endsWith("ol")); //falseSystem.out.println("查找字符串：");System.out.println(str.indexOf("e"));System.out.println(str.indexOf('l'));System.out.println(str.lastIndexOf('e'));System.out.println("字符串截取：");System.out.println(str.substring(1, 3));System.out.println("字符串拆分：");String s = "this is a string";String strs[] = s.split(" "); //以空格拆分for (int i=0; i<strs.length; i++){System.out.println(strs[i]);}
}