1.请编写程序,校验键盘录入的用户名密码与已创建的用户信息是否一致,并测试。
import java.util.Scanner;
public class test {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("用户名:");
String username = sc.nextLine();
System.out.println("密码:");
String password = sc.nextLine();
boolean flag = check(username,password);
System.out.println(flag);
}
public static boolean check(String username,String password){
if("admin".equals(username)&&"123456".equals(password)){
return true;
}else{
return false;
}
}
}
2.校验键盘录入的用户名是否为正确的格式,并测试。
正确格式要求(用户名长度必须为6-16位数字或字母)
import java.util.Scanner;
public class test {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("用户名");
String username = sc.nextLine();
boolean flag = check(username);
System.out.println(flag);
}
public static boolean check(String username){
boolean flag = true;
if(username.length()>=6&&username.length()<=16){
for(int i=0;i<username.length();i++){
char ch = username.charAt(i);
if((!(ch>='0'&&ch<='9')||(ch>='a'&&ch<='z')||(ch>'A'&&ch<='Z'))){
flag=false;
break;
}
}
}else{
flag = false;
}
return flag;
}
}
3.将键盘录入的字符串倒序打印,并测试。
例: 键盘输入:abcde
打印输出:edcba
import java.util.Scanner;
public class test {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
String str = sc.nextLine();
reversePrint(str);
}
private static void reversePrint(String str) {
for(int i=str.length()-1;i>=0;i--){
System.out.println((str.charAt(i)));
}
}
}
4.统计键盘录入的字符串中包含大写字母、小写字母、数字的个数,并测试。
import java.util.Scanner;
public class test {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
String str = sc.nextLine();
printcount(str);
}
private static void printcount(String str) {
int bigcount=0,smallcount=0,numcount=0;
for(int i=0;i<str.length();i++){
char ch = str.charAt(i);
if(ch>='0'&&ch<='9'){
numcount++;
}else if(ch>='a'&&ch<='z'){
smallcount++;
}else if(ch>='A'&&ch<='Z'){
bigcount++;
}
}
System.out.println("大写字母为:"+bigcount);
System.out.println("小写字母为:"+smallcount);
System.out.println("数字为:"+numcount);
}
}
5.将键盘录入的字符串中敏感字符过滤掉,并测试。
例: 敏感字: 奥巴马、普京
键盘输入: 我喜欢奥巴马呀,还喜欢普京
打印输出: 我喜欢呀,还喜欢
package org.westos.demo18;
import java.util.Scanner;
public class test {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
String str = sc.nextLine();
String resultStr = stringFilter(str);
System.out.println(resultStr);
}
private static String stringFilter(String str) {
String[] filters = {"奥巴马","金正恩","普金"};
for(int i=0;i<filters.length;i++){
String filter = filters[i];
str = str.replace(filter,"*");
}
return str;
}
}
6.统计键盘录入的字符串中出现了几次字符串”java”,并测试
例: 键盘输入:woyaoxuejava,xihuanjava,aijava,javajavawozuiai
package org.westos.demo19;
import java.util.Scanner;
public class test {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
String str = sc.nextLine();
int count = countTotal(str, "java");
System.out.println(count);
}
private static int countTotal(String str, String java) {
int count = 0;
while(str.contains("java")){
count++;
int index = str.indexOf("java");
str = str.substring(index+1);
}
return count;
}
}