这里，我使用了两个类来组合序列化和反序列化以及集合的概念。运行程序时，出现运行时异常“ NoSuchElementException”。
我已经使用Employee类存储Employee的基本信息。
DemoEmployee类是声明四个方法的主类。
要反序列化链接列表对象
如何解决此问题？
import java.io.Serializable;
public class Employee_6033 implements Serializable {
private int empid_6033;
private String empname_6033;
private String empdes_6033;
private int empsalary_6033;
public Employee_6033(int empid_6033, String empname_6033, String empdes_6033, int empsalary_6033) {
// TODO Auto-generated constructor stub
this.empid_6033 = empid_6033;
this.empname_6033 = empname_6033;
this.empdes_6033 = empdes_6033;
this.empsalary_6033 = empsalary_6033;
}
int getEmpId_6033() {
return empid_6033;
}
String getEmpName_6033() {
return empname_6033;
}
String getEmpDes_6033() {
return empdes_6033;
}
int getEmpSalary_6033() {
return empsalary_6033;
}
}
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.LinkedList;
import java.util.List;
import java.util.Scanner;
public class DemoEmployee_6033 {
static List<Employee_6033> l_6033 = new LinkedList<Employee_6033>();
int n_6033;
int i_3033;
void addEmployee_6033() {
Scanner input = new Scanner(System.in);
System.out.println("Enter the number of employees : ");
n_6033 = input.nextInt();
for (i_3033 = 1; i_3033 <= n_6033; i_3033++) {
System.out.println("\nEnter Employee " + i_3033 + "'s Details :");
System.out.print("\tEnter ID : ");
int id_6033 = input.nextInt();
input.nextLine();
System.out.print("\tEnter Name : ");
String name_6033 = input.nextLine();
System.out.print("\tEnter Designation : ");
String des_6033 = input.nextLine();
System.out.print("\tEnter Salary : ");
int salary_6033 = input.nextInt();
l_6033.add(new Employee_6033(id_6033, name_6033, des_6033, salary_6033));
}
input.close();
}
void display_6033() {
int j_6033 = 1;
for (Employee_6033 ref_6033 : l_6033) {
System.out.println("Employee " + j_6033);
System.out.println("\tID : " + ref_6033.getEmpId_6033());
System.out.println("\tName : " + ref_6033.getEmpName_6033());
System.out.println("\tDesignation : " + ref_6033.getEmpDes_6033());
System.out.println("\tSalary : " + ref_6033.getEmpSalary_6033());
j_6033++;
}
}
void serialize_6033() {
try {
String filename_6033 = "";
Scanner input = new Scanner(System.in);
System.out.print("Enter the name of the file you want to Read from : ");
filename_6033 = input.nextLine();
// Saving of object in a file
FileOutputStream file_6033 = new FileOutputStream(filename_6033);
ObjectOutputStream out_6033 = new ObjectOutputStream(file_6033);
// Method for serialization of object
out_6033.writeObject(l_6033);
out_6033.close();
file_6033.close();
System.out.println("Object has been serialized");
input.close();
}
catch (IOException ex) {
System.out.println("IOException is caught");
}
}
void deserialize_6033() {
l_6033 = null;
try {
String filename_6033;
Scanner input = new Scanner(System.in);
System.out.print("Enter the name of the file you want to Write to : ");
filename_6033 = input.nextLine();
// Reading the object from a file
FileInputStream file_6033 = new FileInputStream(filename_6033);
ObjectInputStream in_6033 = new ObjectInputStream(file_6033);
// Method for deserialization of object
l_6033 = (List<Employee_6033>) in_6033.readObject();
in_6033.close();
file_6033.close();
System.out.println("Object has been deserialized ");
display_6033();
input.close();
}
catch (IOException ex) {
System.out.println("IOException is caught");
}
catch (ClassNotFoundException ex) {
System.out.println("ClassNotFoundException is caught");
}
}
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner input = new Scanner(System.in);
DemoEmployee_6033 de_6033 = new DemoEmployee_6033();
int choice_6033;
do {
System.out.println("\n********* MENU *********");
System.out.println("--------------------------");
System.out.println("1. Add Employee");
System.out.println("2. Display Employee Details");
System.out.println("3. Write Data into a File - Serialization");
System.out.println("4. Read Data from a File - Deserialization");
System.out.println("5. Exit");
System.out.println("--------------------------");
System.out.print("Enter you Choice : ");
choice_6033 = input.nextInt(); //Error comes here after 1 iteration.
switch (choice_6033) {
case 1:
de_6033.addEmployee_6033();
break;
case 2:
de_6033.display_6033();
break;
case 3:
de_6033.serialize_6033();
break;
case 4:
de_6033.deserialize_6033();
break;
case 5:
break;
default:
System.out.println("You have entered an invalid choice!");
break;
}
} while (choice_6033 != 5);
input.close();
}
}
NoSuchElementException被抛出，因为您广泛地调用了input.close()，在这种情况下，它只能被调用一次。我已经删除了所有出现的内容（main方法除外），并且您的代码工作正常。
出于这个原因，实际上，调用Scanner.close()会关闭整个System.in，并且每个以后相关的方法调用（例如您的情况下的input.nextInt()都会导致异常。