2.1 (Y. Daniel Liang英文版第11版P492：12.2*)

(NumberFormatException) Write

a program that prompts the user to read two integers and displays their sum. Your

program should prompt the user to read the number again if the input is incorrect.

12.2（InputMismatchException异常）编写一个程序，提示用户读取两个整数，然后显示他们的和。程序应该在输入不正确时提示用户在此读取数值。

package 异常类处理与捕获;
import java.util.Scanner;
import java.util.InputMismatchException;
public class zhengshuhe {public static void main(String[] args) {	Scanner scanner=new Scanner(System.in);while(true) {try {System.out.println("请输入第一个数字：");int num1=scanner.nextInt();System.out.println("请输入第二个数字：");int num2=scanner.nextInt();int sum=num1+num2;System.out.println("两数之和为："+sum);break;}catch(InputMismatchException e) {System.out.println("输入不正确，请重新输入：");scanner.nextLine();}}}

 

2.2 (Y. Daniel Liang英文版第11版P492：12.3* )

(ArrayIndexOutBoundsException) Write a program that meets the following

requirements:

■ Create an array with 100 randomly chosen integers

■ Prompt the user to enter the index of the array, then display the corresponding

element value. If the specified index is out of bounds, display the message Out of

Bounds.

package 异常类处理与捕获;
import java.util.Scanner;
import java.util.Random;
public class suijishuzu {public static void main(String[] args) {Scanner scanner=new Scanner(System.in);int[] a=new int[100];Random b=new Random();for(int i=0;i<100;i++) {a[i]=b.nextInt(10)+1;}while(true) {try {System.out.println("请输入想要查询的数组元素的下标：");int k=scanner.nextInt();System.out.println(a[k]);break;}catch(ArrayIndexOutOfBoundsException e){System.out.println("0边界的UT");System.out.println("请重新输入：");scanner.nextLine();}}}
}

2.3 (Y. Daniel Liang英文版第11版P492：12.4* )

(IllegalArgumentException)

Modify the Loan class in Listing 10.2 to throw IllegalArgumentException if the loan

amount, interest rate, or number of years is less than or equal to zero.

修改程序清单10-2中的Loan类，如果贷款总额、利率、年数小于或等于零，则抛出IllegalArgumentException异常

package 异常类处理与捕获;
import java.util.Scanner;
class Loan{
private double annualInterestRate;
private int numberOfYears;
private double loanAmount;
public Loan(double annualInterestRate,int numberOfYears,double loanAmount) {
if(annualInterestRate<=0||numberOfYears<=0||loanAmount<=0) {
throw new IllegalArgumentException("贷款金额、利率或者年数不能小于或等于0");
}
this.annualInterestRate=annualInterestRate;
this.numberOfYears=numberOfYears;
this.loanAmount=loanAmount;
}
public double getAnnualInterestRate() {
return annualInterestRate;
}
public int getNumberOfYears() {
return numberOfYears;
}
public double getLoanAmount() {
return loanAmount;
}
}
public class lilv {
public static void main(String[] args) {
Scanner scanner=new Scanner(System.in);
System.out.println("请输入贷款金额、利率以及年数：");
double a=scanner.nextDouble();
int b=scanner.nextInt();
double c=scanner.nextDouble();
try {
Loan loan=new Loan(a,b,c);
}
catch(IllegalArgumentException e){
System.out.println("错误："+e.getMessage());
System.out.println("请重新输入贷款金额、利率以及年数");
scanner.nextLine();
}
}
}

2.4 (Y. Daniel Liang英文版第11版P494 )*12.15

(Write/read data) Write a

program to create a file named Exercise12_15.txt if it does not exist. Write 100

integers created randomly into the file using text I/O. Integers are separated by spaces

in the file. Read the data back from the file and display the data in increasing order.

（本题使用第 12 章讲的文本 I/O 做，即 Scanner 和 PrintWriter 类进行文本输入输

出。）

（写/读数据）写一个
程序创建一个名为 Exercise12_15.txt的文件（如果它不存在）。写100
使用文本I/O随机创建到文件中的整数。整数用空格分隔
文件里有。从文件中读回数据，并按增加的顺序显示数据。
（本题使用第 12 章讲的文本I/O做，即Scanner和Print Writer类进行文本输入输
出。）

package 异常类处理与捕获;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.PrintWriter;
import java.util.Random;
import java.util.Scanner;
public class wenjian12_15 {public static void main(String[] args) {String filePath = "E:\\eclipse-java-2023-12-R-win32-x86_64\\异常类处理与捕获\\src\\异常类处理与捕获\\练习 12_15.txt";/*每个人路径不一样更改路径即可*/createFileWithRandomIntegers(filePath);readAndSortData(filePath);}public static void createFileWithRandomIntegers(String filePath) {try (PrintWriter writer = new PrintWriter(new File(filePath))) {Random random = new Random();for (int i = 0; i < 100; i++) {writer.print(random.nextInt(1000) + " ");}} catch (FileNotFoundException e) {e.printStackTrace();}}public static void readAndSortData(String filePath) {try (Scanner scanner = new Scanner(new File(filePath))) {int[] numbers = new int[100];int index = 0;while (scanner.hasNextInt()) {numbers[index++] = scanner.nextInt();}java.util.Arrays.sort(numbers);for (int num : numbers) {System.out.println(num);}} catch (FileNotFoundException e) {e.printStackTrace();}}
}

 

2.5 (Y. Daniel Liang英文版第11版P715：*17.3)

(Sum all the integers in a binary

data file) Suppose a binary data file named Exercise17_03.dat has been created and its

data are created using writeInt(int) in DataOutputStream. The file contains an

unspecified number of integers. Write a program to find the sum of the integers.

（将所有整数合并为二进制
假设创建了一个名为Exercise17_03.dat的二进制数据文件，并且它的
数据是使用 DataOutputStream中的writeInt（int）创建的。该文件包含一个
未指定整数数目。写一个程序来求整数之和。

package 异常类处理与捕获;
import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.IOException;public class jijjjj {
public static void main(String[] args) {
int sum = 0;
try (DataInputStream dis = new DataInputStream(new FileInputStream("E:\\eclipse-java-2023-12-R-win32-x86_64\\异常类处理与捕获\\src\\异常类处理与捕获\\练习 17_03.DAT"))) {
while (dis.available() > 0) {
sum += dis.readInt();
}
} catch (IOException e) {
e.printStackTrace();
}
System.out.println("整数总和为: " + sum);
}
}

 

2.6(Y. Daniel Liang英文版第11版P716：*17.5)

(Store objects and arrays in a file)

Write a program that stores an array of the five int values 1, 2, 3, 4, and 5, a Date

object for the current time, and the double value 5.5 into the file named

Exercise17_05.dat.

（将对象和数组存储在文件中）
编写一个程序，存储由五个int值1、2、3、4、5组成的数组，一个日期
当前时间的对象，并将双值5.5放入名为“
演习17_05.dat。

2.6
package 异常类处理与捕获;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.Date;public class erjinzhi{
public static void main(String[] args) {
String filePath = "E:\\eclipse-java-2023-12-R-win32-x86_64\\异常类处理与捕获\\src\\异常类处理与捕获\\Exercise17_05.dat";
int[] arr = {1, 2, 3, 4, 5};
Date currentTime = new Date();
double n = 5.5;
try (ObjectOutputStream outputStream = new ObjectOutputStream(new FileOutputStream(filePath))) {
outputStream.writeObject(arr);
outputStream.writeObject(currentTime);
outputStream.writeDouble(n);
} catch (IOException e) {
e.printStackTrace();
}try (ObjectInputStream inputStream = new ObjectInputStream(new FileInputStream(filePath))) {
int[] readArray = (int[]) inputStream.readObject();
Date readTime = (Date) inputStream.readObject();
double readDouble = inputStream.readDouble();
System.out.println("读取的数组: " + java.util.Arrays.toString(readArray));
System.out.println("读取的时间: " + readTime);
System.out.println("读取的双精度数: " + readDouble);
} catch (IOException | ClassNotFoundException e) {
e.printStackTrace();
}
}
}