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Java系统服务案例

wen java案例 1

本文目录导读：

Java系统服务案例

  1. 项目结构
  2. 核心代码实现
  3. API测试示例

我来为您提供一个基于Spring Boot的完整Java系统服务案例，这个案例演示了一个简单的用户管理系统,包含常见的业务逻辑。

项目结构

user-management-system/
├── pom.xml
├── src/main/java/com/example/usermanagement/
│   ├── UserManagementApplication.java
│   ├── controller/
│   │   └── UserController.java
│   ├── service/
│   │   ├── UserService.java
│   │   └── impl/
│   │       └── UserServiceImpl.java
│   ├── repository/
│   │   └── UserRepository.java
│   ├── entity/
│   │   └── User.java
│   ├── dto/
│   │   ├── UserDTO.java
│   │   └── UserCreateRequest.java
│   └── exception/
│       ├── GlobalExceptionHandler.java
│       └── UserNotFoundException.java

核心代码实现

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 
         http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.7.14</version>
        <relativePath/>
    </parent>
    <groupId>com.example</groupId>
    <artifactId>user-management</artifactId>
    <version>1.0.0</version>
    <name>user-management-system</name>
    <description>用户管理系统服务</description>
    <properties>
        <java.version>11</java.version>
    </properties>
    <dependencies>
        <!-- Spring Web -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!-- Spring Data JPA -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <!-- 数据校验 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-validation</artifactId>
        </dependency>
        <!-- H2数据库（开发环境） -->
        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
            <scope>runtime</scope>
        </dependency>
        <!-- Lombok -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <!-- Spring测试 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>
</project>

实体类 User.java

package com.example.usermanagement.entity;
import lombok.Data;
import org.hibernate.annotations.CreationTimestamp;
import org.hibernate.annotations.UpdateTimestamp;
import javax.persistence.*;
import javax.validation.constraints.Email;
import javax.validation.constraints.NotBlank;
import java.time.LocalDateTime;
@Data
@Entity
@Table(name = "users")
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    @NotBlank(message = "用户名不能为空")
    @Column(nullable = false, unique = true, length = 50)
    private String username;
    @NotBlank(message = "邮箱不能为空")
    @Email(message = "邮箱格式不正确")
    @Column(nullable = false, unique = true, length = 100)
    private String email;
    @Column(length = 20)
    private String phone;
    @Column(nullable = false)
    private Boolean active = true;
    @CreationTimestamp
    @Column(name = "created_at", updatable = false)
    private LocalDateTime createdAt;
    @UpdateTimestamp
    @Column(name = "updated_at")
    private LocalDateTime updatedAt;
}

DTO类

UserDTO.java

package com.example.usermanagement.dto;
import lombok.Data;
import java.time.LocalDateTime;
@Data
public class UserDTO {
    private Long id;
    private String username;
    private String email;
    private String phone;
    private Boolean active;
    private LocalDateTime createdAt;
    private LocalDateTime updatedAt;
}

UserCreateRequest.java

package com.example.usermanagement.dto;
import lombok.Data;
import javax.validation.constraints.Email;
import javax.validation.constraints.NotBlank;
import javax.validation.constraints.Pattern;
@Data
public class UserCreateRequest {
    @NotBlank(message = "用户名不能为空")
    @Pattern(regexp = "^[a-zA-Z0-9_]{3,20}$", 
             message = "用户名只能包含字母、数字和下划线，长度3-20")
    private String username;
    @NotBlank(message = "邮箱不能为空")
    @Email(message = "邮箱格式不正确")
    private String email;
    @Pattern(regexp = "^1[3-9]\\d{9}$", 
             message = "手机号格式不正确")
    private String phone;
    private Boolean active = true;
}

仓库接口

package com.example.usermanagement.repository;
import com.example.usermanagement.entity.User;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.query.Param;
import org.springframework.stereotype.Repository;
import java.util.List;
import java.util.Optional;
@Repository
public interface UserRepository extends JpaRepository<User, Long> {
    Optional<User> findByUsername(String username);
    Optional<User> findByEmail(String email);
    boolean existsByUsername(String username);
    boolean existsByEmail(String email);
    @Query("SELECT u FROM User u WHERE u.active = :active ORDER BY u.createdAt DESC")
    List<User> findByActive(@Param("active") Boolean active);
    @Query("SELECT u FROM User u WHERE LOWER(u.username) LIKE LOWER(CONCAT('%', :keyword, '%')) " +
           "OR LOWER(u.email) LIKE LOWER(CONCAT('%', :keyword, '%'))")
    List<User> searchUsers(@Param("keyword") String keyword);
}

服务层

UserService.java (接口)

package com.example.usermanagement.service;
import com.example.usermanagement.dto.UserCreateRequest;
import com.example.usermanagement.dto.UserDTO;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import java.util.List;
public interface UserService {
    UserDTO createUser(UserCreateRequest request);
    UserDTO getUserById(Long id);
    UserDTO getUserByUsername(String username);
    List<UserDTO> getAllUsers();
    Page<UserDTO> getUsersByPage(Pageable pageable);
    UserDTO updateUser(Long id, UserCreateRequest request);
    void deleteUser(Long id);
    List<UserDTO> searchUsers(String keyword);
    UserDTO toggleUserStatus(Long id);
}

UserServiceImpl.java

package com.example.usermanagement.service.impl;
import com.example.usermanagement.dto.UserCreateRequest;
import com.example.usermanagement.dto.UserDTO;
import com.example.usermanagement.entity.User;
import com.example.usermanagement.exception.UserNotFoundException;
import com.example.usermanagement.exception.UsernameAlreadyExistsException;
import com.example.usermanagement.repository.UserRepository;
import com.example.usermanagement.service.UserService;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.BeanUtils;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import java.util.List;
import java.util.stream.Collectors;
@Service
@Slf4j
@RequiredArgsConstructor
@Transactional
public class UserServiceImpl implements UserService {
    private final UserRepository userRepository;
    @Override
    public UserDTO createUser(UserCreateRequest request) {
        log.info("Creating new user: {}", request.getUsername());
        // 检查用户名是否已存在
        if (userRepository.existsByUsername(request.getUsername())) {
            throw new UsernameAlreadyExistsException("用户名已存在: " + request.getUsername());
        }
        // 检查邮箱是否已存在
        if (userRepository.existsByEmail(request.getEmail())) {
            throw new RuntimeException("邮箱已存在: " + request.getEmail());
        }
        User user = new User();
        BeanUtils.copyProperties(request, user);
        User savedUser = userRepository.save(user);
        log.info("User created successfully: {}", savedUser.getId());
        return convertToDTO(savedUser);
    }
    @Override
    @Transactional(readOnly = true)
    public UserDTO getUserById(Long id) {
        User user = userRepository.findById(id)
                .orElseThrow(() -> new UserNotFoundException("用户不存在: id=" + id));
        return convertToDTO(user);
    }
    @Override
    @Transactional(readOnly = true)
    public UserDTO getUserByUsername(String username) {
        User user = userRepository.findByUsername(username)
                .orElseThrow(() -> new UserNotFoundException("用户不存在: username=" + username));
        return convertToDTO(user);
    }
    @Override
    @Transactional(readOnly = true)
    public List<UserDTO> getAllUsers() {
        return userRepository.findAll()
                .stream()
                .map(this::convertToDTO)
                .collect(Collectors.toList());
    }
    @Override
    @Transactional(readOnly = true)
    public Page<UserDTO> getUsersByPage(Pageable pageable) {
        return userRepository.findAll(pageable)
                .map(this::convertToDTO);
    }
    @Override
    public UserDTO updateUser(Long id, UserCreateRequest request) {
        User user = userRepository.findById(id)
                .orElseThrow(() -> new UserNotFoundException("用户不存在: id=" + id));
        // 检查用户名是否被其他用户使用
        if (!user.getUsername().equals(request.getUsername()) && 
            userRepository.existsByUsername(request.getUsername())) {
            throw new UsernameAlreadyExistsException("用户名已存在: " + request.getUsername());
        }
        user.setUsername(request.getUsername());
        user.setEmail(request.getEmail());
        user.setPhone(request.getPhone());
        User updatedUser = userRepository.save(user);
        log.info("User updated successfully: {}", updatedUser.getId());
        return convertToDTO(updatedUser);
    }
    @Override
    public void deleteUser(Long id) {
        User user = userRepository.findById(id)
                .orElseThrow(() -> new UserNotFoundException("用户不存在: id=" + id));
        userRepository.delete(user);
        log.info("User deleted successfully: {}", id);
    }
    @Override
    @Transactional(readOnly = true)
    public List<UserDTO> searchUsers(String keyword) {
        return userRepository.searchUsers(keyword)
                .stream()
                .map(this::convertToDTO)
                .collect(Collectors.toList());
    }
    @Override
    public UserDTO toggleUserStatus(Long id) {
        User user = userRepository.findById(id)
                .orElseThrow(() -> new UserNotFoundException("用户不存在: id=" + id));
        user.setActive(!user.getActive());
        User updatedUser = userRepository.save(user);
        return convertToDTO(updatedUser);
    }
    private UserDTO convertToDTO(User user) {
        UserDTO dto = new UserDTO();
        BeanUtils.copyProperties(user, dto);
        return dto;
    }
}

控制器层

package com.example.usermanagement.controller;
import com.example.usermanagement.dto.UserCreateRequest;
import com.example.usermanagement.dto.UserDTO;
import com.example.usermanagement.service.UserService;
import lombok.RequiredArgsConstructor;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.annotation.*;
import javax.validation.Valid;
import java.util.List;
@RestController
@RequestMapping("/api/users")
@RequiredArgsConstructor
@Validated
public class UserController {
    private final UserService userService;
    // 创建用户
    @PostMapping
    public ResponseEntity<UserDTO> createUser(@Valid @RequestBody UserCreateRequest request) {
        UserDTO createdUser = userService.createUser(request);
        return new ResponseEntity<>(createdUser, HttpStatus.CREATED);
    }
    // 获取所有用户
    @GetMapping
    public ResponseEntity<List<UserDTO>> getAllUsers() {
        return ResponseEntity.ok(userService.getAllUsers());
    }
    // 分页查询用户
    @GetMapping("/page")
    public ResponseEntity<Page<UserDTO>> getUsersByPage(
            @RequestParam(defaultValue = "0") int page,
            @RequestParam(defaultValue = "10") int size,
            @RequestParam(defaultValue = "createdAt") String sortBy,
            @RequestParam(defaultValue = "desc") String sortDirection) {
        Sort.Direction direction = sortDirection.equalsIgnoreCase("desc") ? 
                                  Sort.Direction.DESC : Sort.Direction.ASC;
        Pageable pageable = PageRequest.of(page, size, Sort.by(direction, sortBy));
        return ResponseEntity.ok(userService.getUsersByPage(pageable));
    }
    // 搜索用户
    @GetMapping("/search")
    public ResponseEntity<List<UserDTO>> searchUsers(@RequestParam String keyword) {
        return ResponseEntity.ok(userService.searchUsers(keyword));
    }
    // 获取用户详情
    @GetMapping("/{id}")
    public ResponseEntity<UserDTO> getUserById(@PathVariable Long id) {
        return ResponseEntity.ok(userService.getUserById(id));
    }
    // 更新用户
    @PutMapping("/{id}")
    public ResponseEntity<UserDTO> updateUser(
            @PathVariable Long id,
            @Valid @RequestBody UserCreateRequest request) {
        return ResponseEntity.ok(userService.updateUser(id, request));
    }
    // 切换用户状态
    @PatchMapping("/{id}/status")
    public ResponseEntity<UserDTO> toggleUserStatus(@PathVariable Long id) {
        return ResponseEntity.ok(userService.toggleUserStatus(id));
    }
    // 删除用户
    @DeleteMapping("/{id}")
    public ResponseEntity<Void> deleteUser(@PathVariable Long id) {
        userService.deleteUser(id);
        return ResponseEntity.noContent().build();
    }
}

异常处理

package com.example.usermanagement.exception;
import lombok.extern.slf4j.Slf4j;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.validation.FieldError;
import org.springframework.web.bind.MethodArgumentNotValidException;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestControllerAdvice;
import java.time.LocalDateTime;
import java.util.HashMap;
import java.util.Map;
@RestControllerAdvice
@Slf4j
public class GlobalExceptionHandler {
    @ExceptionHandler(UserNotFoundException.class)
    public ResponseEntity<ErrorResponse> handleUserNotFound(UserNotFoundException ex) {
        log.error("User not found: {}", ex.getMessage());
        ErrorResponse error = new ErrorResponse(
            HttpStatus.NOT_FOUND.value(),
            ex.getMessage(),
            LocalDateTime.now()
        );
        return new ResponseEntity<>(error, HttpStatus.NOT_FOUND);
    }
    @ExceptionHandler(UsernameAlreadyExistsException.class)
    public ResponseEntity<ErrorResponse> handleUsernameExists(UsernameAlreadyExistsException ex) {
        log.error("Username already exists: {}", ex.getMessage());
        ErrorResponse error = new ErrorResponse(
            HttpStatus.CONFLICT.value(),
            ex.getMessage(),
            LocalDateTime.now()
        );
        return new ResponseEntity<>(error, HttpStatus.CONFLICT);
    }
    @ExceptionHandler(MethodArgumentNotValidException.class)
    public ResponseEntity<Map<String, String>> handleValidationErrors(
            MethodArgumentNotValidException ex) {
        Map<String, String> errors = new HashMap<>();
        ex.getBindingResult().getAllErrors().forEach((error) -> {
            String fieldName = ((FieldError) error).getField();
            String errorMessage = error.getDefaultMessage();
            errors.put(fieldName, errorMessage);
        });
        return new ResponseEntity<>(errors, HttpStatus.BAD_REQUEST);
    }
    @ExceptionHandler(Exception.class)
    public ResponseEntity<ErrorResponse> handleGenericException(Exception ex) {
        log.error("Unexpected error occurred", ex);
        ErrorResponse error = new ErrorResponse(
            HttpStatus.INTERNAL_SERVER_ERROR.value(),
            "服务器内部错误",
            LocalDateTime.now()
        );
        return new ResponseEntity<>(error, HttpStatus.INTERNAL_SERVER_ERROR);
    }
    record ErrorResponse(int status, String message, LocalDateTime timestamp) {}
}

配置文件 application.yml

# 服务器配置
server:
  port: 8080
  servlet:
    context-path: /
# Spring配置
spring:
  application:
    name: user-management-service
  # 数据库配置
  datasource:
    url: jdbc:h2:mem:userdb;DB_CLOSE_DELAY=-1
    driver-class-name: org.h2.Driver
    username: sa
    password: 
  # JPA配置
  jpa:
    hibernate:
      ddl-auto: create-drop
    show-sql: true
    properties:
      hibernate:
        format_sql: true
  # H2控制台
  h2:
    console:
      enabled: true
      path: /h2-console
# 日志配置
logging:
  level:
    root: INFO
    com.example.usermanagement: DEBUG
    org.springframework.web: INFO

主启动类

package com.example.usermanagement;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.data.jpa.repository.config.EnableJpaAuditing;
@SpringBootApplication
@EnableJpaAuditing
public class UserManagementApplication {
    public static void main(String[] args) {
        SpringApplication.run(UserManagementApplication.class, args);
    }
}

API测试示例

# 创建用户
POST http://localhost:8080/api/users
{
    "username": "zhangsan",
    "email": "zhangsan@example.com",
    "phone": "13800138000",
    "active": true
}
# 获取所有用户
GET http://localhost:8080/api/users
# 分页查询
GET http://localhost:8080/api/users/page?page=0&size=10&sortBy=createdAt&sortDirection=desc
# 搜索用户
GET http://localhost:8080/api/users/search?keyword=zhang
# 获取用户详情
GET http://localhost:8080/api/users/1
# 更新用户
PUT http://localhost:8080/api/users/1
{
    "username": "zhangsan_updated",
    "email": "zhangsan_updated@example.com",
    "phone": "13800138001",
    "active": true
}
# 切换用户状态
PATCH http://localhost:8080/api/users/1/status
# 删除用户
DELETE http://localhost:8080/api/users/1

这个案例包含了以下核心功能：

  1. RESTful API 设计
  2. 数据持久化 (JPA)
  3. 参数校验
  4. 异常处理
  5. 分页和搜索
  6. 事务管理
  7. 日志记录

这是一个完整的企业级系统服务案例,可以直接运行和测试。

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