项目用到的知识点：

IO流技术

网络编程技术

序列化

多线程

File等等

说明：

1). 客户端和服务器端采用 TCP 连接；

2). 数据保存在服务器端以txt文件保存；

3). 客户端增删改查发送数据格式说明：

a). 添加： "[1] 数据 " ，例如： "[1] 李明明 , 男 ,22" ，意思：没有 id 字段，由服务器端在写入数据前自动添加。

b). 根据 id 查询一条数据： "[2]id" ，例如： "[2]1" ，意思：查询 id 为 1 的学员信息

c). 修改一条数据： "[3] 新数据 " 。例如："[3]1,李明明, 女 ,19" ，意思：将 id=1 的学员改为后面的新数据。

d). 查询所有数据： "[4]" 。例如： "[4]" ，意思：后面不用带任何数据。

e). 删除一条数据： "[5]id" 。例如： "[5]1" ，意思：删除 id 为 1 的记录。

客户端：

package com.hh.client.pojo;

import java.io.Serializable;

public class Student implements Serializable {

    private int id;
    private String name;
    private String sex;
    private int age;

    public Student() {
    }

    public Student( String name, String sex, int age) {
        this.name = name;
        this.sex = sex;
        this.age = age;
    }

    public Student(int id, String name, String sex, int age) {
        this.id = id;
        this.name = name;
        this.sex = sex;
        this.age = age;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return "Student{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", sex='" + sex + '\'' +
                ", age=" + age +
                '}';
    }
}

package com.hh.client.utils;

import com.hh.server.pojo.Student;

import java.util.ArrayList;

public class StudentUtils {

    public static void printStudentList(ArrayList<Student> students){
        System.out.println("-------------------------------------");
        System.out.println("编号\t\t姓名\t\t性别\t\t年龄");
        for (Student student : students) {
            System.out.println(student.getId()+"\t\t"+student.getName()+"\t\t"+student.getSex()+"\t\t"+student.getAge());
        }
        System.out.println("-------------------------------------");
    }

    public static  void printStudent(Student student){
        System.out.println("-------------------------------------");
        System.out.println("编号\t\t姓名\t\t性别\t\t年龄");
        System.out.println(student.getId()+"\t\t"+student.getName()+"\t\t"+student.getSex()+"\t\t"+student.getAge());
    }

}

package com.hh.client;

import com.hh.server.pojo.Student;
import com.hh.client.utils.StudentUtils;

import java.io.*;
import java.net.Socket;
import java.util.ArrayList;
import java.util.Scanner;

public class Client {
    public static Scanner scanner = new Scanner(System.in);
    public static void main(String[] args) {
        System.out.println("---欢迎使用学生管理系统---");
        while (true){
            System.out.println("【1】添加学生【2】修改学生【3】删除学生【4】查询学生【5】查询所有学生 【6】退出");
            System.out.println("请输入：");
            int type = Integer.parseInt(scanner.nextLine());
            switch (type){
                case 1:
                    addStudent();
                    break;
                case 2:
                    modifyStudent();
                    break;
                case 3:
                    deleteStudent();
                    break;
                case 4:
                    findByIdStudent();
                    break;
                case 5:
                    findAllStudent();
                    break;
                case 6:
                    System.exit(0);
                    break;
                    default:
                        System.out.println("输入错误，请重新输入！");
                        break;
            }
        }
    }

    //添加学生
    private static void addStudent() {
        System.out.println("---添加学生---");
        System.out.println("请输入姓名：");
        String name = scanner.nextLine();
        System.out.println("请输入性别：");
        String sex = scanner.nextLine();
        System.out.println("请输入年龄：");
        String age = scanner.nextLine();
        if (name.isEmpty()||sex.isEmpty()||age.isEmpty()){
            System.out.println("姓名，性别，年龄不能为空");
            return;
        }
        //获取客户端
        Socket socket = getSocket();
        if (socket==null){
            System.out.println("---服务器暂时无法连接---");
            return;
        }
        try(OutputStream outputStream = socket.getOutputStream();
            InputStream inputStream = socket.getInputStream();){
            //向服务器传入数据
            outputStream.write(("[1]"+name+","+sex+","+age).getBytes());
            //从服务器获取数据
            int result = inputStream.read();
            if (result==1){
                System.out.println("---添加成功---");
            }else{
                System.out.println("---添加失败，请重新添加---");
            }
            socket.close();
        }catch (IOException e){
           e.printStackTrace();
       }
    }

    //修改学生
    private static void modifyStudent() {
        System.out.println("---修改学生---");
        System.out.println("请输入学生id：");
        String sid = scanner.nextLine();
        if (sid.isEmpty()){
            System.out.println("学生id不能为空");
            return;
        }
        Socket socket = getSocket();
        if (socket==null){
            System.out.println("---服务器暂时无法连接---");
            return;
        }
        Student student = null;
        try(OutputStream outputStream = socket.getOutputStream();
            InputStream inputStream = socket.getInputStream();) {
            outputStream.write(("[4]"+sid).getBytes());

            ObjectInputStream objectInputStream = new ObjectInputStream(inputStream);
            student = (Student)objectInputStream.readObject();
            if (student==null){
                System.out.println("查无此人");
                return;
            }else{
                StudentUtils.printStudent(student);
            }
            socket.close();
        }catch (IOException e){
            e.printStackTrace();
        }catch (ClassNotFoundException e){
            e.printStackTrace();
        }

        //以上内容为修改信息之前，先进行信息的查询，然后在进行修改
        System.out.println("请输入新的姓名：(若不修改输入0)：");
        String name = scanner.nextLine();
        System.out.println("请输入新的性别：(若不修改输入0)：");
        String sex = scanner.nextLine();
        System.out.println("请输入新的年龄：（若不修改输入0）:");
        String age = scanner.nextLine();

       if (!"0".equals(name)){
           student.setName(name);
       }
       if (!"0".equals(sex)){
           student.setSex(sex);
       }
       if (!"0".equals(age)){
           student.setAge(Integer.parseInt(age));
       }

        Socket insertSocket = getSocket();
       if (insertSocket==null){
           System.out.println("---服务器暂时无法连接---");
            return;
       }
       try (OutputStream outputStream = insertSocket.getOutputStream();
            InputStream inputStream = insertSocket.getInputStream();){
           outputStream.write(("[2]"+student.getName()+","+student.getSex()+","+student.getAge()).getBytes());

           int read = inputStream.read();
           if (read==1){
               System.out.println("修改成功");
           }else{
               System.out.println("修改失败，请稍后重试");
           }
           //释放资源
            insertSocket.close();
       }catch (IOException e){
           e.printStackTrace();
       }
    }

    //删除学生
    private static void deleteStudent() {
        System.out.println("---删除学生---");
        System.out.println("请输入你要删除学生的id:");
        String sid = scanner.nextLine();

        Socket deleteSocket = getSocket();
        if (deleteSocket==null){
            System.out.println("----服务器暂时无法连接----");
            return;
        }
        Student student =null;
        try (OutputStream outputStream = deleteSocket.getOutputStream();
             InputStream inputStream = deleteSocket.getInputStream();){
            outputStream.write(("[4]"+sid).getBytes());
            ObjectInputStream objectInputStream = new ObjectInputStream(inputStream);
            student =(Student ) objectInputStream.readObject();
            if (student==null){
                System.out.println("---查无此人---");
                return;
            }else{
                StudentUtils.printStudent(student);
            }
            deleteSocket.close();
        }catch (IOException e){
            e.printStackTrace();
        }catch (ClassNotFoundException e){
            e.printStackTrace();
        }

        System.out.println("你确定要删除以上信息的学生吗（y/n）?");
        String user = scanner.nextLine();
        if (!"y".equals(user)){
            System.out.println("---删除操作已经取消---");
            return;
        }
        Socket socket = getSocket();
        if (socket==null){
            System.out.println("----服务器暂时无法连接----");
            return;
        }
        try( OutputStream outputStream = socket.getOutputStream();
             InputStream inputStream = socket.getInputStream();) {
           outputStream.write(("[3]"+sid).getBytes());
            int read = inputStream.read();
            if (read==1){
                System.out.println("删除成功");
            }else{
                System.out.println("删除失败，请稍后重试");
            }
            //释放资源
            socket.close();
        }catch (IOException e){}

    }

    //通过id查询学生
    private static void findByIdStudent() {
        System.out.println("---通过id查询学生---");
        System.out.println("请输入你要查询学生的id:");
        String sid = scanner.nextLine();

        Socket findSocket = getSocket();
        if (findSocket==null){
            System.out.println("-----服务器暂时无法连接-----");
            return;
        }
        Student student =null;
        try (OutputStream outputStream = findSocket.getOutputStream();
             InputStream inputStream = findSocket.getInputStream();){
            outputStream.write(("[4]"+sid).getBytes());
            ObjectInputStream objectInputStream = new ObjectInputStream(inputStream);
            student =(Student) objectInputStream.readObject();
            if (student==null){
                System.out.println("---查无此人---");
                return;
            }else{
                StudentUtils.printStudent(student);
            }
            findSocket.close();
        }catch (IOException e){
            e.printStackTrace();
        }catch (ClassNotFoundException e){
            e.printStackTrace();
        }

    }
    //查询所有学生
    private static void findAllStudent() {
        System.out.println("---查询所有学生---");
        Socket allSocket = getSocket();
        if (allSocket==null){
            System.out.println("--服务器暂时无法连接---");
            return;
        }
        try(OutputStream outputStream = allSocket.getOutputStream();
            InputStream inputStream = allSocket.getInputStream();) {
            outputStream.write("[5]".getBytes());
            ObjectInputStream objectInputStream = new ObjectInputStream(inputStream);
            ArrayList<Student> students = (ArrayList<Student>) objectInputStream.readObject();
            System.out.println("student===="+students.size());
            Student student = students.get(0);
            System.out.println(student.getId());
            System.out.println(student.getName());
            System.out.println(student.getSex());
            if (students==null||students.size()==0){
                System.out.println("暂无学生信息");
            }else{
                StudentUtils.printStudentList(students);
            }
            allSocket.close();
        }catch (IOException e){
            e.printStackTrace();
        }catch (ClassNotFoundException e){
            e.printStackTrace();
        }
    }

    //创建客户端
    public static Socket getSocket(){
        Socket socket = null;
        try{
            socket = new Socket("127.0.0.1",8888);
        }catch (IOException e){
            e.printStackTrace();
        }
        return socket;
    }

}

服务器端：

package com.hh.server;

import com.hh.server.utils.ServerThread;

import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;

//一.业务功能： 1).接收客户端连接；
// 2).开启线程(ServerThread类)

public class Server {
    public static void main(String[] args) throws  IOException{
        ServerSocket serverSocket = getServerSocket();
        if (serverSocket==null){
            System.out.println("服务器启动失败");
            return;
        }
        while (true){
            System.out.println("等待客户端连接...");
            Socket accept = serverSocket.accept();
            //开启新线程
           new ServerThread(accept).start();
        }
    }

    public static ServerSocket getServerSocket(){
        ServerSocket serverSocket =null;
        try {
            serverSocket = new ServerSocket(8888);
        }catch (IOException e){
            e.printStackTrace();
        }
        return  serverSocket;
    }
}

package com.hh.server.utils;

import com.hh.server.pojo.Student;

import java.io.*;
import java.util.ArrayList;

public class ServerUtils {

    public static void writeAll(ArrayList<Student> students){
        try( FileWriter fileWriter = new FileWriter("students.txt",false);) {
            for (Student student : students) {
                fileWriter.write(student.getId()+","+student.getName()+","+student.getSex()+","+student.getAge());
                fileWriter.write("\r\n");
            }
        }catch (Exception e){
            e.printStackTrace();
        }
    }

    //读取所有学生信息
    public static ArrayList<Student> readAll(){
        ArrayList<Student> students = new ArrayList<>();

        File file = new File("students.txt");
        if (!file.exists()){
            try {
                file.createNewFile();
            }catch (Exception e){
                e.printStackTrace();
            }
        }

        try ( BufferedReader bufferedReader = new BufferedReader(new FileReader("students.txt"));){
            String line = null;
            while ((line=bufferedReader.readLine())!=null){
                String[] infoStudent = line.split(",");
                Student student = new Student();
                student.setId(Integer.parseInt(infoStudent[0]));
                student.setName(infoStudent[1]);
                student.setSex(infoStudent[2]);
                student.setAge(Integer.parseInt(infoStudent[3]));
                students.add(student);
            }
        }catch (IOException e){
            e.printStackTrace();
            return null;
        }
        return students;
    }

    public static  boolean addStudent(Student student){
        ArrayList<Student> students = readAll();
        if (students==null){
            System.out.println("文件读取失败");
            return false;
        }
        if (students.size()!=0){
            student.setId(students.get(students.size()-1).getId()+1);
        }else{
            student.setId(1);
        }
        students.add(student);
        writeAll(students);
        return true;
    }


    public static boolean deleteById(String id){
        ArrayList<Student> students = readAll();
        if (students==null){
            System.out.println("读取文件失败");
            return false;
        }
        for (Student student : students) {
            if (student.getId()== Integer.parseInt(id)){
                students.remove(student);
                writeAll(students);
                return true;
            }
        }
        return false;
    }

    public static boolean modify(Student student){
        //1.先读取所有学生
        ArrayList<Student> stuList = readAll();
        if (stuList == null) {//说明读取文件出错
            System.out.println("读取文件失败");
            return false;
        }
        System.out.println("修改的数据：" + student);
        //2.遍历集合
        for (int i = 0; i < stuList.size(); i++) {
            Student stu = stuList.get(i);
            //3.判断哪个学生id和要修改的学生id相同
            if (stu.getId() == student.getId()) {
                //4.将学生改为新的学生
                stuList.set(i, student);
                //5.重写将集合写入到文集中
                writeAll(stuList);//写回文件
                //6.返回成功
                return true;
            }
        }
        //7.返回失败
        return false;//没找到
    }

    //根据id查询学生,返回查询到的学生
    public static Student findStudentById(String id) {
        //1.先读取所有学生
        ArrayList<Student> stuList = readAll();
        if (stuList == null) {//说明读取文件出错
            System.out.println("读取文件失败");
            return null;
        }
        //2.遍历集合
        for (int i = 0; i < stuList.size(); i++) {
            Student stu = stuList.get(i);
            //3.比较id
            if (stu.getId() == Integer.parseInt(id)) {
                //4.找到返回学生对象
                return stu;
            }
        }
        //5.找不到返回null
        return null;
    }
}

package com.hh.server.utils;

import com.hh.server.pojo.Student;

import java.io.*;
import java.net.Socket;
import java.util.ArrayList;

public class ServerThread extends Thread{

    private Socket socket;

    public ServerThread(Socket socket) {
        this.socket = socket;
    }

    @Override
    public void run() {

        try (InputStream inputStream = socket.getInputStream();
             OutputStream outputStream = socket.getOutputStream();){
            byte[] bs = new byte[1024];
            int len = inputStream.read(bs);
            String bsStr = new String(bs, 0, len);
            System.out.println("客户端的数据为："+bsStr);
            if (bsStr.charAt(0)!='['||bsStr.charAt(2) !=']'){
                System.out.println("客户端数据格式有误");
                outputStream.write("-1".getBytes());
                outputStream.close();
                inputStream.close();
                socket.close();
                return;
            }
            String num = bsStr.substring(1, 2);
            String contentStr =bsStr.substring(3);
            //判断
            //【1】添加学生【2】修改学生【3】删除学生【4】查询学生【5】查询所有学生
            switch (num){
                case "1":
                    addStudent(contentStr);
                    break;
                case "2":
                    modifyStudent(contentStr);
                    break;
                case "3":
                    deleteStudent(contentStr);
                    break;
                case "4":
                    findByIdStudent(contentStr);
                    break;
                case "5":
                    findAllStudents();
                    break;
                    default:
                        System.out.println("客户端信息有误");
                        socket.close();
                        break;
            }

        }catch (IOException e){
            e.printStackTrace();
        }
    }


    //【1】添加学生【2】修改学生【3】删除学生【4】查询学生【5】查询所有学生
    //查询学生  4 ，通过id
    private void findByIdStudent(String contentStr) {
        Student studentById = ServerUtils.findStudentById(contentStr);
        try {
            OutputStream out = socket.getOutputStream();
            ObjectOutputStream oos = new ObjectOutputStream(out);
            oos.writeObject(studentById);
            oos.close();
            out.close();
            socket.close();
        } catch (IOException ie) {
            ie.printStackTrace();
        }
    }

    //删除学生 3
    private void deleteStudent(String contentStr) {
        ServerUtils.deleteById(contentStr);
        try {
            OutputStream out = socket.getOutputStream();
            out.write(1);
            out.close();
            socket.close();
        } catch (IOException ie) {
            ie.printStackTrace();
        }
    }

    //查询所有学生
    private void findAllStudents() {
        ArrayList<Student> students = ServerUtils.readAll();
        try {
            OutputStream out = socket.getOutputStream();
            ObjectOutputStream oos = new ObjectOutputStream(out);
            oos.writeObject(students);
            //释放资源
            oos.close();
            out.close();
            socket.close();
        } catch (IOException ie) {
            ie.printStackTrace();
        }
    }

    //修改学生
    private void modifyStudent(String contentStr) {
        String[] stuInfo = contentStr.split(",");
        Student student = new Student(Integer.parseInt(stuInfo[0]),stuInfo[1], stuInfo[2],Integer.parseInt(stuInfo[3]));
        ServerUtils.modify(student);
        try( OutputStream outputStream = socket.getOutputStream();) {
            outputStream.write(1);
            socket.close();
        }catch (Exception e){
            e.printStackTrace();
        }

    }

    //添加学生
    private void addStudent(String contentStr) {
        String[] stuInfo = contentStr.split(",");
        Student student = new Student(stuInfo[0], stuInfo[1],Integer.parseInt(stuInfo[2]));
        ServerUtils.addStudent(student);
        try( OutputStream outputStream = socket.getOutputStream();) {
            outputStream.write(1);
            socket.close();
        }catch (Exception e){
            e.printStackTrace();
        }
    }


}

扫描二维码关注公众号，回复： 11110693 查看本文章