一、String字符串练习

public class StringExercises {

public static void main(String[] args) {
    test6();
}


//1.编写程序将 “jdk” 全部变为大写,并输出到屏幕,
//截取子串”DK” 并输出到屏幕
public static void test1() {
    String s = "jdk";
    s = s.toUpperCase();
    System.out.println(s);
    String substring = s.substring(1);
    System.out.println(substring);
}

//2.编写程序将String类型字符串”test” 变为 “tset”.
public static void test2() {
    String s = "test";
    StringBuilder sb = new StringBuilder(s);

    System.out.println(sb.reverse().toString());
}

//3.写一个方法判断一个字符串是否对称
public static void test3() {
    String s = "abcdcba";
    StringBuilder sb = new StringBuilder(s);
    String reverse = sb.reverse().toString();
    if(s.equals(reverse)) {
        System.out.println("字符串  "+s+" 是对称的");
    } else {
        System.out.println("字符串  "+ s +" 不对称");
    }
}

//String s = "113@ ere qqq yyui" 输出所有
//不包含特殊字符的字符串
public static void test4() {
    String s = "113@ ere qqq yyui";
    s = s.replace("@", "");
    String[] split = s.split(" ");
    for(String str : split) {
        System.out.println(str);
    }
}

//编写一个程序，将下面的一段文本中的各个单词的字母顺序翻转，
//“To be or not to be."，将变成"oT eb ro ton ot eb."。
public static void test5() {
    String s = "To be or not to be.";
    s = s.replace(".", "");
    String[] split = s.split(" ");
    StringBuilder result = new StringBuilder();
    for(String str : split) {
        StringBuilder sb = new StringBuilder(str);
        str = sb.reverse().append(" ").toString();
        result.append(str);
    }
    result.replace(result.length() - 1, result.length(), ".");
    System.out.println(result.toString());
    //方法2：转换为一个字符数组，然后末尾添加一个句号
//，开始去掉一个句号
    char[] chars = s.toCharArray();
    for (int i = chars.length - 1; i >= 1; i--) {
        System.out.print(chars[i]);
    }
    System.out.print(".");
}

/**
 * 6.String s=”name=zhangsan age=18 classNo=090728”;
将上面的字符串拆分，结果如下:
zhangsan 180 90728
 */
public static void test6() {
    String s= "name=zhangsan age=18 classNo=090728";
    String[] split = s.split(" ");
    StringBuilder sb = new StringBuilder();
    for(String str : split) {
        int index = str.indexOf("=");
        str = str.substring(index+1)+" ";
        sb.append(str);
    }
    System.out.println(sb);
}

}