自定义异常

一、

编写注册方法，判断注册的参数mobile是11位数字，否则抛出异常IllegalMobileException，调用者捕获异常并提示"手机不合法"。

SignupDemo.java:

public class SignupDemo {public static void main(String[] args) {String mobile = "12121121";String pass = "121212";try {boolean f = signup(mobile, pass);} catch (IllegalMobileException e) {System.out.println("手机不合法");}}public static boolean signup(String mobile, String pass) throws IllegalMobileException {if (mobile.length() != 11) {throw new IllegalMobileException();}return false;}}

IllegalMobileException.java:

public class IllegalMobileException extends Exception {public IllegalMobileException() {super();}public IllegalMobileException(String msg) {super(msg);}}

二、学生登录，如果学号和密码不匹配，显示登录不成功，否则显示登录成功；另外，如果学号不是10位数字抛出自定义异常。IllegalStudentNumException继承运行时异常RuntimeException。

Student.java:

public class Student{public Student(){}public Student(String studentNo,String pass){this.studentNo = studentNo;this.pass = pass;}private String studentNo;private String pass;public String getStudentNo() {return studentNo;}public String getPass() {return pass;}public boolean equals(Object obj) {return super.equals(obj);}}

SigninDemo.java:

public class SigninDemo {static List<Student> students=Arrays.asList(new Student("2015010101","1223"),new Student("2015010102","1234"),new Student("2015010112","2312"));public static void main(String[] args) {String mobile="12121121";String pass="121212";try {if(signin(mobile,pass)){System.out.println("成功登陆");}else{System.out.println("学号或密码不正确");}} catch (IllegalStudentNumException e) {System.out.println("学号格式不合法");}}public static boolean checkStuNo(String stuno) throws IllegalStudentNumException{if (stuno.length() != 10) {throw new IllegalStudentNumException();}return true;}private static boolean signin(String stuno, String pass)throws IllegalStudentNumException{//判断stuno 为10位数字 不为十位数字抛出异常if(checkStuNo(stuno)){Student stu=new Student(stuno,pass);return students.contains(stu);}return false;}}

IllegalStudentNumException.java:

public class IllegalStudentNumException extends RuntimeException{public IllegalStudentNumException(){super();}public IllegalStudentNumException(String msg){super(msg);}}

三、在集合中存储着三个用户，分别为："张三", "1234"；"李四", "1232"；"王五", "1231"。现实现控制台登录功能：

（1）密码正确：登录成功，任意键退出；

（2）用户名存在，密码错误：提示重新登录；

（3）用户名不存在，抛出自定义的NoUserFoundException，接收此异常后提示用户名不存在。

UserLogin.java:

public class UserLogin {// 初始化用户信息static UserInfo[] map = new UserInfo[3];static {map[0] = new UserInfo("张三", "1234");map[1] = new UserInfo("李四", "1232");map[2] = new UserInfo("王五", "1231");}public static void main(String[] args) {// main中捕获异常进行处理提示：用户名不存在boolean isExit = false;String username = "李四";String pass = "1232";try {isExit = login(username, pass);if (isExit) {System.out.println("登录成功");} else {System.out.println("密码错误");}} catch (NoUserFoundException e) {System.out.println("用户名不存在");}}public static boolean login(String username, String pass) throws NoUserFoundException {int i = containsUser(username);if (pass.equals(map[i].getPassword())) {return true;} else {return false;}}public static int containsUser(String username) throws NoUserFoundException {for (int i = 0; i < map.length; i++) {if (username.equals(map[i].getUsername())) {return i;}}throw new NoUserFoundException();}}

UserInfo.java:

public class UserInfo {private String username;private String password;public UserInfo() {}public UserInfo(String username, String password) {this.username = username;this.password = password;}public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}@Overridepublic String toString() {return "username:" + this.getUsername() + ";password:"+ this.getPassword();}}

NoUserFoundException.java:

public class NoUserFoundException extends Exception{public NoUserFoundException() {super();}public NoUserFoundException(String msg) {super(msg);}}