在 Spring Boot 中,实现分页查询有多种方式,下面我将介绍几种常见的分页实现方法,包括 Spring Data JPA 分页、MyBatis 分页、手动分页等。
1. Spring Data JPA 分页
这是最简单和常用的分页方式,Spring Data JPA 内置了分页支持。
1.1 基本实现
首先,添加依赖:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>com.mysql</groupId>
<artifactId>mysql-connector-j</artifactId>
</dependency>
实体类:
@Entity
@Table(name = "users")
public class User {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String name;
private String email;
// getters, setters, constructors...
}
Repository 接口:
public interface UserRepository extends JpaRepository<User, Long> {
Page<User> findByNameContaining(String name, Pageable pageable);
}
Service 层:
@Service
public class UserService {
@Autowired
private UserRepository userRepository;
public Page<User> getUsersByName(String name, int page, int size) {
Pageable pageable = PageRequest.of(page, size, Sort.by("name").ascending());
return userRepository.findByNameContaining(name, pageable);
}
}
Controller 层:
@RestController
@RequestMapping("/api/users")
public class UserController {
@Autowired
private UserService userService;
@GetMapping
public ResponseEntity<Page<User>> getUsers(
@RequestParam(required = false) String name,
@RequestParam(defaultValue = "0") int page,
@RequestParam(defaultValue = "10") int size) {
return ResponseEntity.ok(userService.getUsersByName(name, page, size));
}
}
1.2 自定义返回结果
有时我们需要自定义返回数据结构:
public class PageResult<T> {
private List<T> content;
private int page;
private int size;
private long totalElements;
private int totalPages;
// getters, setters...
public static <T> PageResult<T> fromPage(Page<T> page) {
PageResult<T> result = new PageResult<>();
result.setContent(page.getContent());
result.setPage(page.getNumber());
result.setSize(page.getSize());
result.setTotalElements(page.getTotalElements());
result.setTotalPages(page.getTotalPages());
return result;
}
}
然后在 Controller 中使用:
@GetMapping("/custom")
public ResponseEntity<PageResult<User>> getUsersCustom(
@RequestParam(required = false) String name,
@RequestParam(defaultValue = "0") int page,
@RequestParam(defaultValue = "10") int size) {
Page<User> userPage = userService.getUsersByName(name, page, size);
return ResponseEntity.ok(PageResult.fromPage(userPage));
}
2. MyBatis 分页
2.1 使用 PageHelper
添加依赖:
<dependency>
<groupId>com.github.pagehelper</groupId>
<artifactId>pagehelper-spring-boot-starter</artifactId>
<version>最新版本</version>
</dependency>
Mapper 接口:
@Mapper
public interface UserMapper {
List<User> findByName(@Param("name") String name);
}
Service 层:
@Service
public class UserService {
@Autowired
private UserMapper userMapper;
public PageInfo<User> getUsersByName(String name, int page, int size) {
PageHelper.startPage(page, size);
List<User> users = userMapper.findByName(name);
return new PageInfo<>(users);
}
}
Controller 层:
@GetMapping("/mybatis")
public ResponseEntity<PageInfo<User>> getUsersMybatis(
@RequestParam(required = false) String name,
@RequestParam(defaultValue = "0") int page,
@RequestParam(defaultValue = "10") int size) {
return ResponseEntity.ok(userService.getUsersByName(name, page, size));
}
2.2 MyBatis-Plus 分页
添加依赖:
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>最新版本</version>
</dependency>
配置分页插件:
@Configuration
public class MybatisPlusConfig {
@Bean
public MybatisPlusInterceptor mybatisPlusInterceptor() {
MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
return interceptor;
}
}
Mapper 接口:
public interface UserMapper extends BaseMapper<User> {
// 继承基本方法
}
Service 层:
@Service
public class UserService {
@Autowired
private UserMapper userMapper;
public IPage<User> getUsersByName(String name, int page, int size) {
QueryWrapper<User> wrapper = new QueryWrapper<>();
wrapper.like("name", name);
return userMapper.selectPage(new Page<>(page, size), wrapper);
}
}
Controller 层:
@GetMapping("/mybatis-plus")
public ResponseEntity<IPage<User>> getUsersMybatisPlus(
@RequestParam(required = false) String name,
@RequestParam(defaultValue = "0") int page,
@RequestParam(defaultValue = "10") int size) {
return ResponseEntity.ok(userService.getUsersByName(name, page, size));
}
3. 手动分页
当数据量不大或需要特殊处理时,可以使用手动分页:
@Service
public class UserService {
@Autowired
private UserRepository userRepository;
public List<User> getUsersManually(String name, int page, int size) {
List<User> allUsers = userRepository.findByNameContaining(name);
int fromIndex = page * size;
if (fromIndex >= allUsers.size()) {
return Collections.emptyList();
}
int toIndex = Math.min(fromIndex + size, allUsers.size());
return allUsers.subList(fromIndex, toIndex);
}
public Map<String, Object> getUsersWithTotal(String name, int page, int size) {
List<User> allUsers = userRepository.findByNameContaining(name);
List<User> pageContent = getUsersManually(name, page, size);
Map<String, Object> result = new HashMap<>();
result.put("content", pageContent);
result.put("currentPage", page);
result.put("pageSize", size);
result.put("totalElements", allUsers.size());
result.put("totalPages", (int) Math.ceil((double) allUsers.size() / size));
return result;
}
}
Controller 层:
@GetMapping("/manual")
public ResponseEntity<Map<String, Object>> getUsersManual(
@RequestParam(required = false) String name,
@RequestParam(defaultValue = "0") int page,
@RequestParam(defaultValue = "10") int size) {
return ResponseEntity.ok(userService.getUsersWithTotal(name, page, size));
}
4. WebMvc 分页参数自动绑定
可以创建一个分页参数类来自动绑定分页参数:
public class PageParam {
@Min(0)
private int page = 0;
@Min(1)
@Max(100)
private int size = 10;
private String sort = "id,asc"; // 格式: field,direction
// getters, setters...
public Pageable toPageable() {
String[] parts = sort.split(",");
if (parts.length == 2) {
return PageRequest.of(page, size,
Sort.by(Sort.Direction.fromString(parts[1]), parts[0]));
}
return PageRequest.of(page, size);
}
}
Controller 使用:
@GetMapping("/auto-page")
public ResponseEntity<Page<User>> getUsersAutoPage(
@RequestParam(required = false) String name,
PageParam pageParam) {
return ResponseEntity.ok(userRepository.findByNameContaining(name, pageParam.toPageable()));
}
5. 响应式分页 (WebFlux)
如果使用 Spring WebFlux:
添加依赖:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-mongodb-reactive</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-webflux</artifactId>
</dependency>
Repository:
public interface ReactiveUserRepository extends ReactiveMongoRepository<User, String> {
Flux<User> findByNameContaining(String name, Pageable pageable);
}
Service:
@Service
public class ReactiveUserService {
@Autowired
private ReactiveUserRepository userRepository;
public Mono<Page<User>> getUsers(String name, int page, int size) {
Pageable pageable = PageRequest.of(page, size);
Flux<User> userFlux = userRepository.findByNameContaining(name, pageable);
Mono<Long> countMono = userRepository.countByNameContaining(name);
return Mono.zip(userFlux.collectList(), countMono)
.map(tuple -> new PageImpl<>(tuple.getT1(), pageable, tuple.getT2()));
}
}
Controller:
@RestController
@RequestMapping("/api/reactive/users")
public class ReactiveUserController {
@Autowired
private ReactiveUserService userService;
@GetMapping
public Mono<ResponseEntity<Page<User>>> getUsers(
@RequestParam(required = false) String name,
@RequestParam(defaultValue = "0") int page,
@RequestParam(defaultValue = "10") int size) {
return userService.getUsers(name, page, size)
.map(ResponseEntity::ok)
.defaultIfEmpty(ResponseEntity.notFound().build());
}
}
总结
Spring Data JPA 分页:最简单,适合大多数 CRUD 应用
MyBatis 分页:
PageHelper:简单易用
MyBatis-Plus:功能更强大
手动分页:灵活,适合特殊需求
自动绑定分页参数:提高代码整洁度
响应式分页:适合响应式应用
根据项目需求和技术栈选择合适的分页方式。对于大多数 Spring Boot 项目,Spring Data JPA 或 MyBatis-Plus 的分页功能已经足够强大且易于使用。