java 简单的学生信息管理 不涉及sql
- Java code
package group7.list;import java.util.*;public class Student { private String sID ; private String sName ; private String sGender ; private int sAge ; Scanner cin = new Scanner(System.in); public Student(){}; public Student(String sID, String sName,String gender, int age ){ this.setsName(sName); this.setsGender(gender); this.setsAge(age); } public void setsID(String sID) { this.sID = sID; } public String getsID() { return sID; } public void setsName(String sName) { this.sName = sName; } public String getsName() { return sName; } public void setsGender(String sGender) { this.sGender = sGender; } public String getsGender() { return sGender; } public void setsAge(int sAge) { this.sAge = sAge; } public int getsAge() { return sAge; } public void addStudent(){ Student s1=new Student(); System.out.println("请输入学生学号："); String ID=cin.nextLine(); s1.setsID(ID); System.out.println("请输入学生姓名："); String name=cin.nextLine(); s1.setsName(name); System.out.println("请输入学生性别："); String gender=cin.nextLine(); s1.setsGender(gender); System.out.println("请输入学生年龄："); int age=cin.nextInt(); s1.setsAge(age); StudentList s=new StudentList(); s.addStudent(s1); } public void deleteStudent(){ System.out.println("请输入需要删除的学生的学号："); String deleteID=cin.nextLine(); int index=Integer.parseInt(deleteID); StudentList s=new StudentList(); s.removeStudent(index); }}- Java code
package group7.list;import java.util.ArrayList;import java.util.Iterator;public class StudentList { ArrayList<Student> stuList=new ArrayList<Student>(); public StudentList(){} public StudentList(Student student){ stuList.add(student); } public void addStudent( Student student){ stuList.add(student); }; public void removeStudent(int index){ stuList.remove(index); }; public void showStudents(){ Iterator<Student> it= stuList.iterator(); while(it.hasNext()){ System.out.println(it.next()+" "); } };}- Java code
package group7.list;import java.util.*;public class StudentListTest { /** * 2、 使用List管理对象集合 1) 新建一个包group_x.list(x表示所在的组号) 2) 在这个包中新建三个类：Student类，StudentList类，StudentListTest类。 Student类主要包括： 3) 完善上面三个类，相关要求参考源代码程序的注释，即根据要求修改源代码程序，给出具体的实现代码。 *@author * @param args */ public static void main(String[] args) { Scanner cin=new Scanner(System.in); Student stu0 = new Student("001","Jack","M",20); Student stu1 = new Student("002","Mike","M",20); Student stu2 = new Student("003","Lisa","F",20); Student stu3 = new Student("004","Linda","F",20); Student stu4 = new Student("005","Harry","M",20); Student stu5 = new Student("006","Jimmy","M",20); StudentList s10=new StudentList(stu0); StudentList s11=new StudentList(stu1); StudentList s12=new StudentList(stu2); StudentList s13=new StudentList(stu3); StudentList s14=new StudentList(stu4); StudentList s15=new StudentList(stu5); StudentListTest s= new StudentListTest(); s.menu(); int choice=cin.nextInt(); switch(choice){ case 1 : { boolean flag=true; while(flag) { Student s1=new Student(); s1.addStudent(); System.out.println("如果想要继续添加请输入y，否则输入n"); String c=cin.next(); if(c=="y") flag=true; else flag=false; } StudentListTest s5=new StudentListTest(); s5.menu(); }; break; case 2 :{ boolean flag=true; while(flag){ Student s1=new Student(); s1.deleteStudent(); System.out.println("如果想要继续删除请输入y，否则输入n"); String c=cin.next(); if(c=="y") flag=true; else flag=false; } StudentListTest s6=new StudentListTest(); s6.menu(); }; break; case 3 :{ StudentList s2=new StudentList(); s2.showStudents(); StudentListTest s7=new StudentListTest(); s7.menu(); }; break; case 4 :{ StudentListTest s8=new StudentListTest(); s8.menu(); }; break; } } private void menu() { System.out.println("<<<请选择你需要的操作>>>"); System.out.println("| 1、添加学生信息 |"); System.out.println("| 2、删除学生信息 |"); System.out.println("| 3、显示学生信息 |"); System.out.println("| 4、退出 |"); System.out.println("************************"); }}
怎样改进这个程序 使得这个程序能够正常运行？
为什么使用功能2的时候会抛出异常？
为什么使用功能3的时候会什么都不显示？
[解决办法]
- Java code
public class StudentListTest { /** * 2、 使用List管理对象集合 1) 新建一个包group_x.list(x表示所在的组号) 2) * 在这个包中新建三个类：Student类，StudentList类，StudentListTest类。 Student类主要包括： * * 3) 完善上面三个类，相关要求参考源代码程序的注释，即根据要求修改源代码程序，给出具体的实现代码。 * * @author * @param args */ public static void main(String[] args) { Scanner cin = new Scanner(System.in); Student stu0 = new Student("001", "Jack", "M", 20); Student stu1 = new Student("002", "Mike", "M", 20); Student stu2 = new Student("003", "Lisa", "F", 20); Student stu3 = new Student("004", "Linda", "F", 20); Student stu4 = new Student("005", "Harry", "M", 20); Student stu5 = new Student("006", "Jimmy", "M", 20); StudentList s10 = new StudentList(stu0); StudentList s11 = new StudentList(stu1); StudentList s12 = new StudentList(stu2); StudentList s13 = new StudentList(stu3); StudentList s14 = new StudentList(stu4); StudentList s15 = new StudentList(stu5); // StudentListTest s = new StudentListTest(); menu(); int choice = cin.nextInt(); switch (choice) { case 1: { boolean flag = true; while (flag) { Student s1 = new Student(); s1.addStudent(); System.out.println("如果想要继续添加请输入y，否则输入n"); String c = cin.next(); if (c != "y") flag = true; } menu(); // StudentListTest s5 = new StudentListTest(); } ; break; case 2: { boolean flag = true; while (flag) { Student s1 = new Student(); s1.deleteStudent(); System.out.println("如果想要继续删除请输入y，否则输入n"); String c = cin.next(); if (c != "y") flag = true; } // StudentListTest s6 = new StudentListTest(); //menu(); } ; break; case 3: { StudentList s2 = new StudentList(); s2.showStudents(); // StudentListTest s7 = new StudentListTest(); menu(); } ; break; case 4: { // StudentListTest s8 = new StudentListTest(); menu(); } ; break; } } private static void menu() { System.out.println("<<<请选择你需要的操作>>>"); System.out.println("| 1、添加学生信息 |"); System.out.println("| 2、删除学生信息 |"); System.out.println("| 3、显示学生信息 |"); System.out.println("| 4、退出 |"); System.out.println("************************"); }}