找不到HATEOAS方法

Question

我的控制器似乎无法找到像"linkTo"这样的HATEOAS方法.

我错过了什么吗？

的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>

    <groupId>org.springframework</groupId>
    <artifactId>provider</artifactId>
    <version>0.1.0</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.1.5.RELEASE</version>
    </parent>

    <dependencies>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!-- Spring Security -->
        <!-- Auto configured, remove dependencies to disable. -->
        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-config</artifactId>
        </dependency>

        <!-- OAuth 2.0 -->
        <dependency>
            <groupId>org.springframework.security.oauth</groupId>
            <artifactId>spring-security-oauth2</artifactId>
            <version>2.0.1.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test-mvc</artifactId>
            <version>1.0.0.M2</version>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
        </dependency>

        <!-- Spring MongoDB -->
        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-mongodb</artifactId>
        </dependency>

        <!-- Spring REST MVC -->
        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-rest-webmvc</artifactId>
        </dependency>

        <!-- Dozer: DTO/Entity Mapper -->
        <dependency>
            <groupId>net.sf.dozer</groupId>
            <artifactId>dozer</artifactId>
            <version>5.3.2</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
        </dependency>

        <dependency>
            <groupId>joda-time</groupId>
            <artifactId>joda-time</artifactId>
        </dependency>

    </dependencies>

    <properties>
        <start-class>com.provider.core.Application</start-class>
    </properties>

    <build>
        <plugins>
            <plugin> 
                <artifactId>maven-compiler-plugin</artifactId> 
            </plugin>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

    <repositories>
        <repository>
            <id>spring-snapshots</id>
            <url>http://repo.spring.io/libs-snapshot</url>
            <snapshots><enabled>true</enabled></snapshots>
        </repository>
    </repositories>
    <pluginRepositories>
        <pluginRepository>
            <id>spring-snapshots</id>
            <url>http://repo.spring.io/libs-snapshot</url>
            <snapshots><enabled>true</enabled></snapshots>
        </pluginRepository>
    </pluginRepositories>
</project>

调节器

package com.provider.core;

import org.dozer.DozerBeanMapper;
import org.dozer.Mapper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;

import com.provider.account.Account;
import com.provider.account.AccountDTO;

@Controller
public class AccountController
{
    private static final Logger logger = LoggerFactory.getLogger(AccountController.class);
    @Autowired private AccountRepository repo;

    @RequestMapping(value = "account", method = RequestMethod.POST)
    public @ResponseBody HttpEntity<AccountDTO> createAccount(@RequestBody AccountDTO accountDto) {
        logger.info("Start createAccount()");
        Mapper mapper = new DozerBeanMapper();
        Account account = mapper.map(accountDto, Account.class);
        Account savedAccount = repo.save(account);
        AccountDTO savedAccountDto = mapper.map(savedAccount, AccountDTO.class);

        // DOES NOT COMPILE "linkto" not defined.
        savedAccountDto.add(linkTo(AccountController.class).slash(savedAccountDto.getId()).withSelfRel());

        return new ResponseEntity<AccountDTO>(savedAccountDto, HttpStatus.OK);
    }
}

Answer 1

如果您使用 HATEOAS v1.0 及更高版本（Spring boot >= 2.2.0），请注意类名已更改。值得注意的是，以下类已被重命名：

• ResourceSupport 变成 RepresentationModel
• Resource 变成 EntityModel
• Resources 变成 CollectionModel
• PagedResources 变成 PagedModel
• ResourceAssembler 变成 RepresentationModelAssembler

此处的官方文档中提供了更多信息。

使用 Spring boot starter 时，以下依赖项足以包含 HATEOAS：

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-hateoas</artifactId>
</dependency>

希望这些信息能帮助像我这样搜索了几个小时来找出为什么Resource课堂没有得到解决的人。

Answer 2

看起来你的POM缺少spring-hateoas依赖性.

所以首先将其添加到pom.xml:

<dependency>
    <groupId>org.springframework.hateoas</groupId>
    <artifactId>spring-hateoas</artifactId>
    <version>0.15.0.RELEASE</version>
</dependency>

然后你可以添加这个静态导入,你的代码应该编译:

import static org.springframework.hateoas.mvc.ControllerLinkBuilder.*

Answer 3

    Add following dependency :-

    <dependency>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-hateoas</artifactId>
     <version>2.4.0</version>
    </dependency>
    
    Follow Sample Code :-
    import static org.springframework.hateoas.server.mvc.WebMvcLinkBuilder.*;
   
    @GetMapping(path = "/users/{id}")
    public EntityModel<User> getUserInfo(@PathVariable int id) {
        User user = userDao.getUser(id);
        
        EntityModel<User> entityModel = EntityModel.of(user);
        Link link = WebMvcLinkBuilder.linkTo(methodOn(this.getClass()).getUserList()).withRel("user-list");
        entityModel.add(link);
        
        if(user == null) {
            throw new UserNotFoundException("User not found with id : "+id);
        }
        return entityModel;
    }

Answer 4

如果您在 eclipse 中使用 HATEOAS（版本：Oxygen.3a Release (4.7.3a)），请注意类名已更改。

Resource changed to EntityModel
Resources changed to CollectionModel

以下链接中的官方文档中提供了更多信息->

https://docs.spring.io/spring-hateoas/docs/current/reference/html/

使用 Spring boot starter 时，您必须使用以下依赖项来包含 HATEOAS：

 <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-hateoas</artifactId>
 </dependency>

演示代码：

EntityModel<Users> resource = new EntityModel<Users>(user);
        ControllerLinkBuilder linkTo = linkTo(methodOn(this.getClass()).retrieveAllUsers());
        resource.add(linkTo.withRel("all-users"));

注意：您必须导入

import static org.springframework.hateoas.server.mvc.ControllerLinkBuilder.*;

希望这些信息有助于找出Resource类没有得到解决的原因！！

Answer 5

在 pom.xml 中添加以下依赖项，它可以解决您的问题。

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-hateoas</artifactId>
</dependency>

如果上述方法不起作用，则可以使用旧版本的 hatos 获得简单的解决方案。

由于新版本的 Hateoas 已完全更改，以下链接可以为您提供帮助。 https://docs.spring.io/spring-hateoas/docs/current/reference/html/

我提到了 Hateoas 方法的一些重大变化

ResourceSupport is now RepresentationModel

Resource is now EntityModel

Resources is now CollectionModel

PagedResources is now PagedModel

LinkDiscoverer API 已移至客户端包。

LinkBuilder 和 EntityLinks API 已移至服务器包中。

ControllerLinkBuilder 已移至 server.mvc 中并已弃用，并由 WebMvcLinkBuilder 取代。

RelProvider 已重命名为 LinkRelationProvider，并返回 LinkRelation 实例而不是字符串。

VndError 已移至 mediatype.vnderror 包