定义IllegalScoreException异常类,代表分数相加后超出合理范围的异常。该异常是checked exception,即希望该异常一定要被捕获处理。
定义IllegalNameException异常类,代表名字设置不合理的异常。该异常是unchecked exception
定义Student类。
属性:
private String name;
private int score;
方法:
toString //自动生成
setter/getter //自动生成
改造setName //如果姓名首字母为数字则抛出IllegalNameException
public int addScore(int score) //如果加分后分数<0 或>100,则抛出IllegalScoreException,加分不成功。
main方法:
输入new则新建学生对象。然后输入一行学生数据,格式为姓名 年龄,接着调用setName,addScore。否则跳出循环。setName不成功则抛出异常,并打印异常信息,然后继续下一行的处理。addScore不成功则抛出异常,并打印异常信息,然后继续下一行的处理。如果2、3都成功,则打印学生信息(toString)如果在解析学生数据行的时候发生其他异常,则打印异常信息,然后继续下一行的处理。Scanner也是一种资源,希望程序中不管有没有抛出异常,都要关闭。关闭后,使用System.out.println("scanner closed")打印关闭信息
注意: 使用System.out.println(e);打印异常信息,e为所产生的异常。
输入样例:
new
zhang 10
new
wang 101
new
wang30
new
3a 100
new
wang 50
other
输出样例:
Student [name=zhang, score=10]
IllegalScoreException: score out of range, score=101
java.util.NoSuchElementException
IllegalNameException: the first char of name must not be digit, name=3a
Student [name=wang, score=50]
scanner closed
答案
import java
.util
.Scanner
;
class IllegalScoreException extends RuntimeException {
String message
;
public IllegalScoreException() {
}
public IllegalScoreException(String message
) {
this.message
= message
;
}
@Override
public String
toString() {
return "IllegalScoreException: score out of range, score=" + message
;
}
}
class IllegalNameException extends RuntimeException {
String message
;
public IllegalNameException() {
}
public IllegalNameException(String message
) {
this.message
= message
;
}
@Override
public String
toString() {
return "IllegalNameException: the first char of name must not be digit, name=" + message
;
}
}
class Student {
private String name
;
private int score
;
public Student(){
this.score
= 0;
}
@Override
public String
toString() {
return "Student [" +
"name=" + name
+
", score=" + score
+
']';
}
public String
getName() {
return name
;
}
public void setName(String name
) {
if (name
.charAt(0) >= '0' && name
.charAt(0) <= '9'){
throw new IllegalNameException(name
);
}
this.name
= name
;
}
public int getScore() {
return score
;
}
public void setScore(int score
) {
this.score
= score
;
}
public int addScore(int score
) throws IllegalScoreException
{
if (this.score
+ score
< 0||this.score
+ score
> 100){
throw new IllegalScoreException(Integer
.toString(this.score
+ score
));
}
setScore(this.score
+ score
);
return this.score
;
}
}
public class Main {
public static void main(String
[] args
) {
Scanner scanner
= new Scanner(System
.in
);
while (scanner
.hasNext()){
String str
= scanner
.next();
if (!str
.equals("new")){
scanner
.close();
System
.out
.println("scanner closed");
break;
}
Student stu
= new Student();
scanner
.nextLine();
String nameAndScore
= scanner
.nextLine();
String
[] arr
= nameAndScore
.split("\\s+");
try{
String name
= arr
[0];
int score
= Integer
.parseInt(arr
[1]);
stu
.setName(name
);
stu
.addScore(score
);
System
.out
.println(stu
);
}catch (IllegalNameException | IllegalScoreException e
){
System
.out
.println(e
);
}catch (Exception e
){
System
.out
.println("java.util.NoSuchElementException");
}
}
}
}