一个基于Spring Boot的简单网吧管理系统的案例代码。这个系统包括用户管理、电脑管理、上机记录管理等功能。代码结构清晰，适合初学者学习和参考。

1. 项目结构

src/main/java/com/example/netbarmanagement├── controller│   ├── ComputerController.java│   ├── UserController.java│   └── RecordController.java├── model│   ├── Computer.java│   ├── User.java│   └── Record.java├── repository│   ├── ComputerRepository.java│   ├── UserRepository.java│   └── RecordRepository.java├── service│   ├── ComputerService.java│   ├── UserService.java│   └── RecordService.java└── NetbarManagementApplication.java

2. 依赖配置 (pom.xml)

<dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-jpa</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>com.h2database</groupId><artifactId>h2</artifactId><scope>runtime</scope></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-thymeleaf</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-validation</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency>
</dependencies>

3. 实体类 (model 包)

Computer.java

package com.example.netbarmanagement.model;import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;@Entity
public class Computer {@Id@GeneratedValue(strategy = GenerationType.IDENTITY)private Long id;private String name;private boolean isOccupied;// Getters and Setterspublic Long getId() {return id;}public void setId(Long id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public boolean isOccupied() {return isOccupied;}public void setOccupied(boolean occupied) {isOccupied = occupied;}
}

User.java

package com.example.netbarmanagement.model;import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;@Entity
public class User {@Id@GeneratedValue(strategy = GenerationType.IDENTITY)private Long id;private String username;private String password;// Getters and Setterspublic Long getId() {return id;}public void setId(Long id) {this.id = id;}public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}
}

Record.java

package com.example.netbarmanagement.model;import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import java.time.LocalDateTime;@Entity
public class Record {@Id@GeneratedValue(strategy = GenerationType.IDENTITY)private Long id;private Long userId;private Long computerId;private LocalDateTime startTime;private LocalDateTime endTime;// Getters and Setterspublic Long getId() {return id;}public void setId(Long id) {this.id = id;}public Long getUserId() {return userId;}public void setUserId(Long userId) {this.userId = userId;}public Long getComputerId() {return computerId;}public void setComputerId(Long computerId) {this.computerId = computerId;}public LocalDateTime getStartTime() {return startTime;}public void setStartTime(LocalDateTime startTime) {this.startTime = startTime;}public LocalDateTime getEndTime() {return endTime;}public void setEndTime(LocalDateTime endTime) {this.endTime = endTime;}
}

4. 仓库接口 (repository 包)

ComputerRepository.java

package com.example.netbarmanagement.repository;import com.example.netbarmanagement.model.Computer;
import org.springframework.data.jpa.repository.JpaRepository;public interface ComputerRepository extends JpaRepository<Computer, Long> {
}

UserRepository.java

package com.example.netbarmanagement.repository;import com.example.netbarmanagement.model.User;
import org.springframework.data.jpa.repository.JpaRepository;public interface UserRepository extends JpaRepository<User, Long> {
}

RecordRepository.java

package com.example.netbarmanagement.repository;import com.example.netbarmanagement.model.Record;
import org.springframework.data.jpa.repository.JpaRepository;public interface RecordRepository extends JpaRepository<Record, Long> {
}

5. 服务层 (service 包)

ComputerService.java

package com.example.netbarmanagement.service;import com.example.netbarmanagement.model.Computer;
import com.example.netbarmanagement.repository.ComputerRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;import java.util.List;@Service
public class ComputerService {@Autowiredprivate ComputerRepository computerRepository;public List<Computer> getAllComputers() {return computerRepository.findAll();}public Computer getComputerById(Long id) {return computerRepository.findById(id).orElse(null);}public Computer saveComputer(Computer computer) {return computerRepository.save(computer);}public void deleteComputer(Long id) {computerRepository.deleteById(id);}
}

UserService.java

package com.example.netbarmanagement.service;import com.example.netbarmanagement.model.User;
import com.example.netbarmanagement.repository.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;import java.util.List;@Service
public class UserService {@Autowiredprivate UserRepository userRepository;public List<User> getAllUsers() {return userRepository.findAll();}public User getUserById(Long id) {return userRepository.findById(id).orElse(null);}public User saveUser(User user) {return userRepository.save(user);}public void deleteUser(Long id) {userRepository.deleteById(id);}
}

RecordService.java

package com.example.netbarmanagement.service;import com.example.netbarmanagement.model.Record;
import com.example.netbarmanagement.repository.RecordRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;import java.util.List;@Service
public class RecordService {@Autowiredprivate RecordRepository recordRepository;public List<Record> getAllRecords() {return recordRepository.findAll();}public Record getRecordById(Long id) {return recordRepository.findById(id).orElse(null);}public Record saveRecord(Record record) {return recordRepository.save(record);}public void deleteRecord(Long id) {recordRepository.deleteById(id);}
}

6. 控制器层 (controller 包)

ComputerController.java

package com.example.netbarmanagement.controller;import com.example.netbarmanagement.model.Computer;
import com.example.netbarmanagement.service.ComputerService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;import java.util.List;@RestController
@RequestMapping("/computers")
public class ComputerController {@Autowiredprivate ComputerService computerService;@GetMappingpublic List<Computer> getAllComputers() {return computerService.getAllComputers();}@GetMapping("/{id}")public Computer getComputerById(@PathVariable Long id) {return computerService.getComputerById(id);}@PostMappingpublic Computer createComputer(@RequestBody Computer computer) {return computerService.saveComputer(computer);}@PutMapping("/{id}")public Computer updateComputer(@PathVariable Long id, @RequestBody Computer computer) {computer.setId(id);return computerService.saveComputer(computer);}@DeleteMapping("/{id}")public void deleteComputer(@PathVariable Long id) {computerService.deleteComputer(id);}
}

UserController.java

package com.example.netbarmanagement.controller;import com.example.netbarmanagement.model.User;
import com.example.netbarmanagement.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;import java.util.List;@RestController
@RequestMapping("/users")
public class UserController {@Autowiredprivate UserService userService;@GetMappingpublic List<User> getAllUsers() {return userService.getAllUsers();}@GetMapping("/{id}")public User getUserById(@PathVariable Long id) {return userService.getUserById(id);}@PostMappingpublic User createUser(@RequestBody User user) {return userService.saveUser(user);}@PutMapping("/{id}")public User updateUser(@PathVariable Long id, @RequestBody User user) {user.setId(id);return userService.saveUser(user);}@DeleteMapping("/{id}")public void deleteUser(@PathVariable Long id) {userService.deleteUser(id);}
}

RecordController.java

package com.example.netbarmanagement.controller;import com.example.netbarmanagement.model.Record;
import com.example.netbarmanagement.service.RecordService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;import java.util.List;@RestController
@RequestMapping("/records")
public class RecordController {@Autowiredprivate RecordService recordService;@GetMappingpublic List<Record> getAllRecords() {return recordService.getAllRecords();}@GetMapping("/{id}")public Record getRecordById(@PathVariable Long id) {return recordService.getRecordById(id);}@PostMappingpublic Record createRecord(@RequestBody Record record) {return recordService.saveRecord(record);}@PutMapping("/{id}")public Record updateRecord(@PathVariable Long id, @RequestBody Record record) {record.setId(id);return recordService.saveRecord(record);}@DeleteMapping("/{id}")public void deleteRecord(@PathVariable Long id) {recordService.deleteRecord(id);}
}

7. 主应用类 (NetbarManagementApplication.java)

package com.example.netbarmanagement;import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;@SpringBootApplication
public class NetbarManagementApplication {public static void main(String[] args) {SpringApplication.run(NetbarManagementApplication.class, args);}
}

8. 配置文件 (application.properties)

spring.datasource.url=jdbc:h2:mem:netbar
spring.datasource.driverClassName=org.h2.Driver
spring.datasource.username=sa
spring.datasource.password=password
spring.jpa.database-platform=org.hibernate.dialect.H2Dialect
spring.h2.console.enabled=true

9. 运行项目

1. 使用 mvn spring-boot:run 命令运行项目。
2. 访问 http://localhost:8080/h2-console 查看H2数据库。
3. 使用API工具（如Postman）测试各个接口。

10. 扩展功能

• 添加用户登录和权限管理（使用Spring Security）。
• 添加计费功能，根据上机时间计算费用。
• 添加前端页面（使用Thymeleaf或Vue.js等前端框架）。

这个案例代码是一个基础的网吧管理系统，适合初学者学习和扩展。你可以根据实际需求进一步开发和优化。