我正在学习 Swagger 以及如何使用 Swagger codegen 生成 REST 客户端。我知道如何用 Swagger 做文档，我也知道如何用 Swagger 生成一个简单的 REST 服务器，但我不知道如何用 Swagger codegen 生成一个简单的 REST 客户端。

例如，我有一个简单的应用程序，它是一个 REST 服务器，我想生成 REST 客户端。我可以用 Swagger codegen 做到这一点吗？

REST 服务器的 Controller :

package com.dgs.spring.springbootswagger.controller;

import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import io.swagger.annotations.ApiParam;
import io.swagger.annotations.ApiResponse;
import io.swagger.annotations.ApiResponses;

@RestController
@RequestMapping("/api/v1")
@Api(value = "Employee Management System", description = "Operations pertaining to employee in Employee Management System")
public class EmployeeController {

     @Autowired
     private EmployeeRepository employeeRepository;

        @ApiOperation(value = "View a list of available employees", response = List.class)
        @ApiResponses(value = {
            @ApiResponse(code = 200, message = "Successfully retrieved list"),
            @ApiResponse(code = 401, message = "You are not authorized to view the resource"),
            @ApiResponse(code = 403, message = "Accessing the resource you were trying to reach is forbidden"),
            @ApiResponse(code = 404, message = "The resource you were trying to reach is not found")
        })
     @GetMapping("/employees")
     public List<Employee> getAllEmployees() {
         return employeeRepository.findAll();
     }

     @ApiOperation(value = "Get an employee by Id")   
     @GetMapping("/employees/{id}")
     public ResponseEntity<Employee> getEmployeeById(
             @ApiParam(value = "Employee id from which employee object will retrieve", required = true) @PathVariable(value = "id") Long employeeId)
             throws ResourceNotFoundException {

          Employee employee = employeeRepository.findById(employeeId)
            .orElseThrow(() -> new ResourceNotFoundException("Employee not found for this id :: " + employeeId));

          return ResponseEntity.ok().body(employee);
     }

     @ApiOperation(value = "Add an employee")
     @PostMapping("/employees")
     public Employee createEmployee(
             @ApiParam(value = "Employee object store in database table", required = true) @Valid @RequestBody Employee employee) {
         return employeeRepository.save(employee);
     }

     @ApiOperation(value = "Update an employee")
     @PutMapping("/employees/{id}")
     public ResponseEntity<Employee> updateEmployee(
             @ApiParam(value = "Employee Id to update employee object", required = true) @PathVariable(value = "id") Long employeeId,
             @ApiParam(value = "Update employee object", required = true) @Valid @RequestBody Employee employeeDetails) throws ResourceNotFoundException {

          Employee employee = employeeRepository.findById(employeeId)
            .orElseThrow(() -> new ResourceNotFoundException("Employee not found for this id :: " + employeeId));

          employee.setEmail(employeeDetails.getEmail());
          employee.setLastName(employeeDetails.getLastName());
          employee.setFirstName(employeeDetails.getFirstName());
          final Employee updatedEmployee = employeeRepository.save(employee);

          return ResponseEntity.ok(updatedEmployee);
     }

     @ApiOperation(value = "Delete an employee")
     @DeleteMapping("/employees/{id}")
     public Map<String, Boolean> deleteEmployee(
             @ApiParam(value = "Employee Id from which employee object will delete from database table", required = true) @PathVariable(value = "id") Long employeeId)
       throws ResourceNotFoundException {

      Employee employee = employeeRepository.findById(employeeId)
        .orElseThrow(() -> new ResourceNotFoundException("Employee not found for this id :: " + employeeId));

      employeeRepository.delete(employee);
      Map<String, Boolean> response = new HashMap<>();
      response.put("deleted", Boolean.TRUE);

      return response;
     }
}

之后我开发了一个简单的 REST 客户端:

package com.dgs.restclient.controllers;

@Controller
public class UpdateController {

    @Autowired
    private EmployeeRestClient restClient;

    @GetMapping("/showStartUpdate")
    public String showStartCheckin() {
        return "startUpdate";
    }

    @PostMapping("/startUpdate")
    public String startCheckIn(@RequestParam("employeeId") Long employeeId, ModelMap modelMap) {

        Employee employee = restClient.findEmployee(employeeId);
        modelMap.addAttribute("employee", employee);

        return "displayEmployeeDetails";
    }

    @PostMapping("/completeUpdate")
    public String completeCheckIn(@RequestParam("employeeId") Long employeeId,
            @RequestParam("employeeFirstName") String employeeFirstName,
            @RequestParam("employeeLastName") String employeeLastName,
            @RequestParam("employeeEmail") String employeeEmail) {

        EmployeeUpdateRequest employeeUpdateRequest = new EmployeeUpdateRequest();
        employeeUpdateRequest.setId(employeeId);
        employeeUpdateRequest.setFirstName(employeeFirstName);
        employeeUpdateRequest.setLastName(employeeLastName);
        employeeUpdateRequest.setEmail(employeeEmail);
        restClient.updateEmployee(employeeUpdateRequest);

        return "updateConfirmation";
    }

}

EmployeeRestClient:

package com.dgs.restclient.integration;

@Component
public class EmployeeRestClientImpl implements EmployeeRestClient {

    private static final String EMPLOYEE_REST_URL = 
            "http://localhost:8080/api/v1/employees/";

    @Override
    public Employee findEmployee(Long id) {

        RestTemplate restTemplate = new RestTemplate();
        Employee employee = restTemplate
                .getForObject(EMPLOYEE_REST_URL + id, Employee.class);

        return employee;
    }

    @Override
    public Employee updateEmployee(EmployeeUpdateRequest request) {

        RestTemplate restTemplate = new RestTemplate();
        restTemplate
                .put(EMPLOYEE_REST_URL + request.getId(), request, Employee.class); 

        Employee employee = restTemplate
                .getForObject(EMPLOYEE_REST_URL + request.getId(), Employee.class);

        return employee;
    }

}

这个 REST Client 是我开发的，我想知道我是否可以使用 Swagger codegen 进行这个 REST Client 开发，如何做？我只需要在 pom.xml 中添加 swagger-codegen-maven-plugin 吗？我听说过添加这个插件和一个 yml 文件，Swagger 将创建 REST 客户端。任何反馈将不胜感激!

最佳答案

是的。您可以使用 swagger-codegen-maven-plugin 生成一个 REST 客户端。但在此之前，您需要在 OpenAPI Specification 中以 YAML 或 JSON 描述 REST API。主要是因为swagger-codegen-maven-plugin只能从本规范中编写的文件生成 REST 客户端。

其他答案假定您需要手动编写规范，而我的解决方案更进一步，可以从 REST Controller 源代码自动生成规范。

^{最新的 OpenAPI 版本是 3.0。但根据您导入的 swagger 注释的包，您使用的是 2.0(或之前)版本。所以我的解决方案假设您使用的是 OpenAPI 2.0。}

生成开放 API 规范

首先，您可以使用 swagger-maven-plugin从 RestController 源代码生成 OpenAPI 规范。基本分析了@RestController中注解的Swagger注解<locations> 中指定的类并将 OpenAPI 规范转储到 /src/main/resources/swagger.json :

<plugin>
    <groupId>com.github.kongchen</groupId>
    <artifactId>swagger-maven-plugin</artifactId>
    <version>3.1.5</version>
    <configuration>
        <apiSources>
            <apiSource>
                <springmvc>true</springmvc>
                <locations>
                    <location>com.dgs.spring.springbootswagger.controller.EmployeeController</location>
                    <location>com.dgs.spring.springbootswagger.controller.FooController</location>
                </locations>
                <schemes>
                    <scheme>http</scheme>
                </schemes>
                <host>127.0.0.1:8080</host>
                <basePath>/</basePath>
                <info>
                    <title>My API</title>
                    <version>1.1.1</version>
                </info>
                <swaggerDirectory>${basedir}/src/main/resources/</swaggerDirectory>
            </apiSource>
        </apiSources>
    </configuration>
    <executions>
        <execution>
            <goals>
                <goal>generate</goal>
            </goals>
        </execution>
    </executions>
</plugin>

执行以下maven命令开始生成:

mvn clean compile

生成 Rest Client

在 swagger.json 之后生成后，您可以将其复制并粘贴到您的客户端项目(例如/src/main/resources/swagger.json)。然后我们可以使用 swagger-codegen-maven-plugin生成 HTTP 客户端。

默认情况下，它会生成 whole maven project其中包括测试用例和其他文档资料。但我想要的只是 HttpClient 的源代码，没有其他东西。经过多次尝试和错误，我确定了以下配置:

<plugin>
    <groupId>io.swagger</groupId>
    <artifactId>swagger-codegen-maven-plugin</artifactId>
    <version>2.4.7</version>
    <executions>
        <execution>
            <goals>
                <goal>generate</goal>
            </goals>
            <configuration>
                <inputSpec>${basedir}/src/main/resources/swagger.json</inputSpec>
                <language>java</language>
                <library>resttemplate</library>
                <output>${project.basedir}/target/generated-sources/</output>

                <apiPackage>com.example.demo.restclient.api</apiPackage>
                <modelPackage>com.example.demo.restclient.model</modelPackage>
                <invokerPackage>com.example.demo.restclient</invokerPackage>

                <generateApiTests>false</generateApiTests>
                <generateModelTests>false</generateModelTests>
                <generateApiDocumentation>false</generateApiDocumentation>
                <generateModelDocumentation>false</generateModelDocumentation>
                <configOptions>
                    <dateLibrary>java8</dateLibrary>
                    <sourceFolder>restclient</sourceFolder>
                </configOptions>
            </configuration>
        </execution>
    </executions>
</plugin>

生成的HTTP客户端基于RestTemplate，会生成到文件夹target/generated-sources/restclient .您可能必须配置 IDE 以导入生成的客户端才能使用它。 (如果是Eclipse，可以在Project Properties中配置 ➡️ Java Build Path ➡️ 添加生成的rest client的文件夹)

要开始生成客户端，只需执行 maven 命令:

mvn clean compile

使用生成的 HTTP 客户端:

ApiClient apiClient = new ApiClient();

//Override the default API base path configured in Maven
apiClient.setBasePath("http://api.example.com/api");

EmployeeManagementSystemApi api = new EmployeeManagementSystemApi(apiClient);
api.getEmployeeById(1l);

注意:

• 如果你遇到 javax/xml/bind/annotation/XmlRootElement使用 java8+ 生成异常，可能需要引用 this .

关于java - 如何使用 Swagger codegen 开发一个简单的 REST 客户端？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/57545884/