Springmvc应用Mongodb分页实现

下面就来详细讲解“SpringMVC应用Mongodb分页实现”的完整攻略。

一、引入依赖

我们首先需要在项目中引入Mongodb和Spring Data Mongodb的依赖：

<dependency>
    <groupId>org.springframework.data</groupId>
    <artifactId>spring-data-mongodb</artifactId>
    <version>2.2.6.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.mongodb</groupId>
    <artifactId>mongo-java-driver</artifactId>
    <version>3.11.1</version>
</dependency>

二、创建实体类

我们需要创建一个实体类，用来和MongoDB数据库中的集合进行映射。比如，我们创建一个User类：

public class User {
    private String id;
    private String name;
    private int age;
    // 省略getter和setter方法...
}

三、定义Repository

我们需要定义一个Repository接口，用来进行CRUD操作。比如，我们创建一个UserRepository接口：

public interface UserRepository extends MongoRepository<User, String> {
    Page<User> findByName(String name, Pageable pageable);
}

在这个接口中，我们定义了一个findByName方法，该方法用于根据name字段进行查询，并且支持分页。其中，Pageable是Spring Data提供的用于封装分页信息的类，它包含了当前页码、每页大小、排序规则等信息。

四、实现Service

我们通过定义一个Service类来调用Repository接口中定义的方法。例如：

@Service
public class UserService {

    @Autowired
    private UserRepository userRepository;

    public Page<User> findUserByName(String name, int pageNum, int pageSize) {
        PageRequest pageRequest = PageRequest.of(pageNum, pageSize);
        return userRepository.findByName(name, pageRequest);
    }
}

上述代码中，我们通过PageRequest创建了一个分页请求对象，然后调用了UserRepository中定义的findByName方法进行查询。

五、创建Controller

最后，我们创建一个Controller类来处理用户请求，并返回数据。例如：

@RequestMapping("/users")
@RestController
public class UserController {

    @Autowired
    private UserService userService;

    @GetMapping
    public Page<User> findUserByName(@RequestParam("name") String name,
                                     @RequestParam("pageNum") int pageNum,
                                     @RequestParam("pageSize") int pageSize) {
        return userService.findUserByName(name, pageNum, pageSize);
    }
}

上述代码中，我们将请求参数name、pageNum和pageSize传递给了UserService中的findUserByName方法进行查询，并返回了查询结果Page。

至此，我们已经完成了“SpringMVC应用MongoDB分页实现”的攻略。如果你想获取更多关于SpringMVC和MongoDB的知识，可以参考以下两个示例：

示例一

创建MongoDB数据库配置类

@Configuration
public class MongoConfig extends AbstractMongoClientConfiguration {

    @Override
    protected String getDatabaseName() {
        return "test";
    }

    @Override
    public MongoClient mongoClient() {
        ConnectionString connectionString = new ConnectionString("mongodb://localhost:27017/test");
        MongoClientSettings mongoClientSettings = MongoClientSettings.builder()
                .applyConnectionString(connectionString)
                .build();
        return MongoClients.create(mongoClientSettings);
    }
}

编写实体类

@Data
@NoArgsConstructor
@AllArgsConstructor
@Document(collection = "user")
public class User {
    @Id
    private String id;
    private String name;
    private int age;
}

编写Repository接口

@Repository
public interface UserRepository extends MongoRepository<User, String> {
    Page<User> findByName(String name, Pageable pageable);
}

编写Service类

@Service
public class UserService {

    @Autowired
    private UserRepository userRepository;

    public Page<User> findUserByName(String name, int pageNum, int pageSize) {
        PageRequest pageRequest = PageRequest.of(pageNum, pageSize);
        return userRepository.findByName(name, pageRequest);
    }
}

编写Controller类

@RestController
@RequestMapping("/user")
public class UserController {

    @Autowired
    private UserService userService;

    /**
     * 根据姓名查询用户列表
     * @param name 姓名
     * @param pageNum 页码
     * @param pageSize 页面大小
     * @return 分页查询结果
     */
    @GetMapping("/list")
    public ResultResponse<Page<User>> queryList(@RequestParam String name,
                                                @RequestParam int pageNum,
                                                @RequestParam int pageSize) {
        Page<User> page = userService.findUserByName(name, pageNum, pageSize);
        return ResultResponse.success(page);
    }
}

示例二

创建MongoDB数据库配置类

@Configuration
@EnableMongoRepositories(basePackages = "io.github.pak3nuh.mg.dao")
public class MongoConfiguration extends AbstractMongoClientConfiguration {

    @Value("${spring.data.mongodb.uri}")
    private String mongoUri;

    @Override
    protected String getDatabaseName() {
        return "pet_store";
    }

    @Override
    public MongoClient mongoClient() {
        return MongoClients.create(mongoUri);
    }
}

编写实体类

@Data
@NoArgsConstructor
@AllArgsConstructor
@Document("pets_data")
public class Pet {

    @Id
    private String id;
    @Indexed
    private String species;
    @Indexed
    private String breed;
    private String name;
    private LocalDate birthDate;
    private List<String> medicalProblems;
    private String reservedBy;
}

编写Repository接口

@Repository
public interface PetRepository extends PagingAndSortingRepository<Pet, String> {

    Page<Pet> findByBreed(final String breed, final Pageable pageable);

    Pet findByReservedBy(final String reservationHandle);
}

编写Service类

@Service
public class PetService {

    @Autowired
    private PetRepository petRepository;

    public Page<Pet> findPetsByBreed(final String breed, final int pageNumber, final int pageSize) {
        PageRequest pageRequest = PageRequest.of(pageNumber, pageSize);
        return petRepository.findByBreed(breed, pageRequest);
    }

    public Pet reserve(final String petId, final String reservationHandle) {
        Optional<Pet> optional = petRepository.findById(petId);
        if (!optional.isPresent()) {
            throw new RuntimeException("Could not find pet: " + petId);
        }
        final Pet pet = optional.get();
        if (StringUtils.hasText(pet.getReservedBy())) {
            throw new RuntimeException("Pet is already reserved for " + pet.getReservedBy());
        }
        pet.setReservedBy(reservationHandle);
        return petRepository.save(pet);
    }

    public void cancelReservation(final String petId, final String cancellationHandle) {
        Optional<Pet> optional = petRepository.findById(petId);
        if (!optional.isPresent()) {
            throw new RuntimeException("Could not find pet: " + petId);
        }
        final Pet pet = optional.get();
        if (cancellationHandle.equals(pet.getReservedBy())) {
            pet.setReservedBy(null);
            petRepository.save(pet);
        } else {
            throw new RuntimeException("Can only cancel reservation for pet made by the handler, "
                    + pet.getReservedBy() + " , but request coming from the handler " + cancellationHandle);
        }
    }
}

编写Controller类

@RestController
@RequestMapping("/pets")
public class PetController {

    @Autowired
    private PetService petService;

    @GetMapping
    public ResponseEntity<?> findPetsByBreed(@RequestParam final String breed,
                                              @RequestParam final int pageNumber,
                                              @RequestParam final int pageSize) {
        return ResponseEntity.ok(
                petService.findPetsByBreed(breed, pageNumber, pageSize)
        );
    }

    @PutMapping("/{id}/reservation")
    public ResponseEntity<?> reservePet(@PathVariable final String id,
                                         @RequestParam final String handler) {
        final Pet pet = petService.reserve(id, handler);
        return ResponseEntity.ok(pet);
    }

    @PutMapping("/{id}/cancellation")
    public ResponseEntity<?> cancelPetReservation(@PathVariable final String id,
                                                   @RequestParam final String handler) {
        petService.cancelReservation(id, handler);
        return ResponseEntity.ok(null);
    }
}

以上就是关于“SpringMVC应用MongoDB分页实现”的攻略和两条示例的详细介绍。希望对你有所帮助！