StudentMangerTestクラス：
package tutorial1;
import java.io.*;
import java.util.ArrayList;
import java.util.Scanner;
public class StudentMangerTest {
public static void main(String[] args) throws IOException {
String fileName="FileToArray.txt";
while(true) {
System.out.println("-----欢迎使用学生信息管理系统-----");
System.out.println("1.查看所有学生");
System.out.println("2.添加学生");
System.out.println("3.删除学生");
System.out.println("4.修改学生");
System.out.println("5.退出");
Scanner sc = new Scanner(System.in);
String choose = sc.nextLine();
switch (choose) {
case "1":
//
findAllArrayList(fileName);
break;
case "2":
//添加
addArrayList(fileName);
break;
case "3":
//删除
delArrayList(fileName);
break;
case "4":
//修改
alterArrayList(fileName);
break;
case "5":
default:
//退出
System.out.println("-----谢谢您的使用-----");
//退出JVM
System.exit(0);
}
}
}
//查询学生信息的方法
public static void findAllArrayList(String fileName) throws IOException {
ArrayList<Student> array=new ArrayList<Student>();
//从文件中读数据到集合
readData(fileName,array);
if(array.size()==0){
System.out.println("无学生信息，请重新选择！");
//return中止，不再继续执行下去
return;
}
System.out.println("ID\t\tNAME\t\tAGE\t\tADDRESS");
for(int x=0;x<array.size();x++){
Student student=array.get(x);
System.out.println(student.getId()+"\t\t"+student.getName()+"\t\t"+student.getAge()+"\t\t"+student.getAddress());
}
}
//添加学生信息的方法
public static void addArrayList(String fileName) throws IOException {
Scanner sc =new Scanner(System.in);
Student student=new Student();
ArrayList<Student> array=new ArrayList<Student>();
//从文件中读数据到集合
readData(fileName,array);
String id;
while(true) {
System.out.print("请输入学生ID：");
id = sc.nextLine();
//判断ID是否重复
boolean flag = false;
for (int x = 0; x < array.size(); x++) {
Student s = array.get(x);
if (s.getId().equals(id)) {
flag = true;
break;
}
}
if (flag == true) {
System.out.println("该学生已经存在!");
} else {
break;
}
}
student.setId(id);
System.out.print("请输入学生NAME：");
String name =sc.nextLine();
student.setName(name);
System.out.print("请输入学生AGE：");
String age =sc.nextLine();
student.setAge(age);
System.out.print("请输入学生ADDRESS：");
String address =sc.nextLine();
student.setAddress(address);
//添加到集合里面
array.add(student);
//把集合中的数据重新写回到文件
writeData(fileName,array);
System.out.println("添加学生信息成功！");
}
//删除学生信息
public static void delArrayList(String fileName) throws IOException {
Scanner sc = new Scanner(System.in);
ArrayList<Student> array=new ArrayList<Student>();
//从文件中读数据到集合
readData(fileName,array);
System.out.println("请输入要删除信息的学生ID：");
String id = sc.nextLine();
boolean flag=false;
for (int x = 0; x < array.size(); x++) {
Student s = array.get(x);
if (s.getId().equals(id)) {
//根据索引删除
array.remove(x);
writeData(fileName,array);
break;
} else {
flag=true;
}
}
if(flag==false){
System.out.println("删除成功!");
}
else{
System.out.println("您索要删除的学生信息不存在，请确认后再输入！");
}
}
//修改指定学号的学生信息
public static void alterArrayList(String fileName) throws IOException {
Scanner sc= new Scanner(System.in);
ArrayList<Student> array=new ArrayList<Student>();
//从文件中读数据到集合
readData(fileName,array);
System.out.print("请输入您想要修改学生的学号：");
String id=sc.nextLine();
int index=-1;
for(int x=0;x<array.size();x++) {
Student s = array.get(x);
if (s.getId().equals(id)) {
index = x;
break;
}
}
if(index==-1){
System.out.println("您想要修改的学生不存在");
}
else{
System.out.print("请输入修改后的学生姓名：");
String name=sc.nextLine();
System.out.print("请输入修改后的学生年龄：");
String age=sc.nextLine();
System.out.print("请输入修改后的学生住址：");
String address=sc.nextLine();
Student student=new Student();
student.setId(id);
student.setName(name);
student.setAge(age);
student.setAddress(address);
array.set(index,student);
writeData(fileName,array);
System.out.println("修改成功");
}
}
//从文件中度数据到集合
public static void readData(String fileName,ArrayList<Student> array) throws IOException {
BufferedReader br = new BufferedReader(new FileReader(fileName));
String end;
while((end=br.readLine())!=null){
String[] strArray = end.split(",");
Student s =new Student();
s.setId(strArray[0]);
s.setName(strArray[1]);
s.setAge(strArray[2]);
s.setAddress(strArray[3]);
array.add(s); //别忘了
}
br.close();
}
//把集合中数据写入文件
public static void writeData(String fileName,ArrayList<Student> array) throws IOException {
BufferedWriter bw = new BufferedWriter(new FileWriter(fileName));
for(int x=0;x<array.size();x++){
StringBuilder sb = new StringBuilder();
Student s = array.get(x);
sb.append(s.getId()).append(",").append(s.getName()).append(",").append(s.getAge()).append(",").append(s.getAddress());
bw.write(sb.toString());
bw.newLine();
bw.flush();
}
bw.close();
}
}
/*
*过程中出现了新值传不过去的问题，发现事set方法全写成一样的了
*添加学生信息方法时，id的定义放在外面，不能放在循环里面，因为循环外，方法里还是需要用到的
*/
学生クラス：
package javalianxi;
public class Student {
private String id;
private String name;
private String age;
private String address;
public Student(){
//无参
}
public Student(String id, String name, String age, String address) {
this.id = id;
this.name = name;
this.age = age;
this.address = address;
//有参
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAge() {
return age;
}
public void setAge(String age) {
this.age = age;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
}