public class StringFunc {

    public static void main(String[] args){
        //字符串拼接
        String str1;
        str1 = "hello";
        String str2 = " world";
        System.out.println(str1+str2);
        //字符串与整数拼接
        int num = 100;
        String socers = "得分:";
        System.out.println(socers + num);
        //字符串与对象拼接
        StringFunc Test = new StringFunc();
        System.out.println(socers + Test);
        //字符串方法总结
        String str3 = "abcdef";
        System.out.println("length: "+str3.length());  //查看字符串长度
        System.out.println("concat: "+"xxx".concat("a"));  //在结尾默认追加字符串
        System.out.println("replace: "+"aaa".replace("a","z"));  //替换字符串种的字符
        System.out.println("isEmpty: "+"".isEmpty());   //判断字符串是否为空
        System.out.println("substring: "+"abcdef".substring(3));   //从首位移除多少个字符
        System.out.println("substring: "+"abcdef".substring(2,5));  //从字符哪截取到哪
        System.out.println("toUpperCase: "+str3.toUpperCase());  //转换小写字母为部大写
        System.out.println("toLowerCase: "+"ABCDEF".toLowerCase());  //转换大写字母为小写
        System.out.println("startsWith: "+"abcd".startsWith("abc"));  //判断以什么开头
        System.out.println("endsWith: "+"edef".endsWith("def")); //判断以什么结尾
        String[] list = "a,b,c,d".split(",");   //字符串根据分隔符转换成列表的操作
        System.out.println("split: "+list[0]+" "+list[1]+" "+list[2]+" "+list[3]); //打印上面的列表值
        //以下仅作了解
        System.out.println("indexOf: "+str3.indexOf(97));   //输入对应ASCII码整数对应字符下标会返回
        System.out.println("indexOf: "+"abc".indexOf("b"));  //判断字符的下标
        System.out.println("hashCode: "+"123".hashCode());  //为这个字符串生成哈希值
        System.out.println("charAt: "+str3.charAt(3));  //返回字符串下表对应的单个字符
        System.out.println("codePointAt: "+str3.codePointAt(1));  //返回字符串对应位置的ASCII码
        System.out.println("codePointBefore: "+str3.codePointBefore(1));  //查看字符串对应位置前一位的ASCII码
        System.out.println("codePointCount: "+str3.codePointCount(1,6));  //查看字符串指定下标长度
        System.out.println("compareTo: "+"z".compareTo("a"));  //对比两个字符串相差多少位（利用ASCII码运算差值）
    }
}