REST api返回json但配置为XML？答案

【问题标题】：REST api returning json but configured as XML?REST api返回json但配置为XML？
【发布时间】：2019-12-17 11:14:10
【问题描述】：

我正在尝试从我的服务器获取 XML 响应，但由于某种原因它仍然返回 JSON。也许我误解了 setAccept 和 setContentType 是什么？目前我在想get请求是在XML中，但客户端只接受/期待json？

我试过设置 headers.setAccept(Arrays.asList(MediaType.APPLICATION_JSON));改为 XML，但它最终给了我一个错误“找不到表示”。我还从 consumes = "" 中取出 JSON，但是当我这样做时它也停止工作了。

RestClient.java

public class RestClient {

     public static void getJsonEmployee(String id) throws JSONException, IOException {

          String uri = "http://localhost:8080/employees/" + id;

             RestTemplate restTemplate = new RestTemplate();

             HttpHeaders headers = new HttpHeaders();
             headers.setAccept(Arrays.asList(MediaType.APPLICATION_JSON));
             headers.setContentType((MediaType.APPLICATION_XML));
             HttpEntity entity = new HttpEntity(headers);


            ResponseEntity<String> response = restTemplate.exchange(uri, HttpMethod.GET, entity, String.class);
             String result = response.getBody();
             System.out.println(result);

         }




public static void postJsonEmployee(String id, String name, String description) {

    final String uri = "http://localhost:8080/employees/";


    Employee newemp = new Employee(id, name, description);


    RestTemplate restTemplate = new RestTemplate();


    HttpHeaders httpHeaders = restTemplate.headForHeaders(uri);


    httpHeaders.setContentType(MediaType.APPLICATION_JSON);


    Employee result = restTemplate.postForObject( uri, newemp, Employee.class);


    httpHeaders.setContentType(MediaType.APPLICATION_JSON);


     }

    public static void main(String[] args) throws IOException, JSONException {

     System.out.println("GET or POST?");
     BufferedReader getpost = new BufferedReader(new InputStreamReader(System.in));
     String selection = getpost.readLine();

     switch(selection) {

     case "GET":

     System.out.println("Type in the employee's ID");
     BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
     String employeeid = reader.readLine();
     getJsonEmployee(employeeid);
     break;

     case "POST":

         System.out.println("Type in the employee's ID");
         Scanner scan = new Scanner(System.in);
         String newid = scan.nextLine();
         System.out.println("Type in the employee's name");
         String newname = scan.nextLine();
         System.out.println("Type in the employee's description");
         String newdesc = scan.nextLine();
         postJsonEmployee(newid, newname, newdesc);
         break;
     }

}
}

EmployeeController.java

@RestController
public class EmployeeController {

    @Autowired
    private EmployeeService employeeService;

    @RequestMapping(path = "/employees", produces = {MediaType.APPLICATION_JSON_VALUE, MediaType.APPLICATION_XML_VALUE}, consumes = {MediaType.APPLICATION_JSON_VALUE, MediaType.APPLICATION_XML_VALUE, MediaType.TEXT_PLAIN_VALUE})
    public @ResponseBody HashMap<String, Employee> retrieveEmployees() {
        return employeeService.retrieveAllEmployees();
    }

    @RequestMapping(path = "/employees/{employeeId}",produces = {MediaType.APPLICATION_JSON_VALUE, MediaType.APPLICATION_XML_VALUE}, consumes = {MediaType.APPLICATION_JSON_VALUE, MediaType.APPLICATION_XML_VALUE, MediaType.TEXT_PLAIN_VALUE})
    public @ResponseBody Employee retrievebyId(@PathVariable String employeeId) {
        return employeeService.retrieveEmployee(employeeId);
    }

    @PostMapping(path="/employees", consumes = {MediaType.APPLICATION_JSON_VALUE, MediaType.APPLICATION_XML_VALUE})
    public ResponseEntity<Void> registeremployee(@RequestBody Employee newemployee) {

        Employee employee = employeeService.addEmployee(newemployee.getId(),newemployee.getName(), newemployee.getDescription());

        if (employee == null)
            return ResponseEntity.noContent().build();

        URI location = ServletUriComponentsBuilder.fromCurrentRequest().path(
                "/{id}").buildAndExpand(employee.getId()).toUri();

        return ResponseEntity.created(location).build();
    }

}

EmployeeService.java

@Component
public class EmployeeService implements Serializable {


    static HashMap<String, Employee> employees = new HashMap<>();

    static {
        //Initialize Data

        Team team1 = new Team("t1", "Java team", "Java Dev Team");

        Employee Joe = new Employee("employee1", "Joe Smith","Human Resources");

        Employee Bob = new Employee("employee2", "Bob Jones",
                "Developer");

        employees.put("employee1", Joe);
        employees.put("employee2", Bob);
    }

    public HashMap<String, Employee> retrieveAllEmployees() {
        return employees;
    }

    public Employee retrieveEmployee(String employeeId) {
        return employees.get(employeeId);
    }
    //private SecureRandom random = new SecureRandom();

    public Employee addEmployee(String id, String name, String description) {

        //String randomId = new BigInteger(130, random).toString(32);
        Employee employee = new Employee(id, name, description);

        employees.put(id, employee);

        return employee;



    }

    public HashMap<String, Employee> getEmployees(){
        return employees;
    }

    public void setEmployees(HashMap<String, Employee> employees) {
        this.employees = employees;
    }


}

Employee.java

@XmlRootElement
public class Employee implements Serializable {

  private String id;

  private String name;

  private String description;
  // private List<Team> teams;

  public Employee() {

  }

  public Employee(String id, String name, String description) {
    this.id = id;
    this.name = name;
    this.description = description;
    // this.teams = teams;

  }

  @XmlAttribute
  public String getId() {
    return id;
  }

  public void setId(String id) {
    this.id = id;
  }

  @XmlElement
  public String getName() {
    return name;
  }

  public void setName(String name) {
    this.name = name;
  }

  @XmlElement
  public String getDescription() {
    return description;
  }

  public void setDescription(String description) {
    this.description = description;
  }

  @Override
  public String toString() {
    return String.format("employee [id=%s, name=%s, description=%s]", id, name, description);
  }

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>2.1.6.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.springboot</groupId>
    <artifactId>employee-model</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>employee-model</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>



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

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
        <groupId>org.glassfish.jaxb</groupId>
        <artifactId>jaxb-runtime</artifactId>
        <version>2.3.2</version>
        </dependency>

            <dependency>
    <groupId>org.codehaus.jackson</groupId>
    <artifactId>jackson-mapper-asl</artifactId>
    <version>1.9.13</version>
</dependency>
        <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-webmvc</artifactId>
    <version>5.1.9.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-core</artifactId>
    <version>5.1.9.RELEASE</version>
</dependency>
    </dependencies>


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



</project>

日志

13:13:09.818 [main] DEBUG org.springframework.web.client.RestTemplate - HTTP GET http://localhost:8080/employees/
13:13:09.831 [main] DEBUG org.springframework.web.client.RestTemplate - Accept=[text/plain, application/json, application/*+json, */*]
13:13:09.857 [main] DEBUG org.springframework.web.client.RestTemplate - Response 200 OK
13:13:09.859 [main] DEBUG org.springframework.web.client.RestTemplate - Reading to [java.lang.String] as "application/json;charset=UTF-8"
{"employee1":{"id":"employee1","name":"Joe Smith","description":"Human Resources"},"employee2":{"id":"employee2","name":"Bob Jones","description":"Developer"}}

【问题讨论】：

你了解Accept 和Content-Type 标头的作用吗？
这不是你的问题的原因（这就是为什么这不是一个答案），但是当你使用@RestController 时你不需要@ResponseBody。
@chrylis 据我了解，Accept 标头说明了客户端可以接受的媒体类型。内容类型标头说明它正在发送什么内容
请包含您的 POM 或 Gradle 构建文件。（作为旁注，您使用了许多看起来很酷但通常被认为是错误的“隐藏依赖”功能；相反，通过构造函数注入您的 EmployeeService，并添加一个 MvcUriComponentsBuilder 作为方法参数。）
@chrylis 我添加了 pom 构建文件

标签： java spring

【解决方案1】：

您使用 MediaType.APPLICATION_XML_VALUE 而不是 MediaType.APPLICATION_XML 是否有任何特殊原因

我宁愿将我的 REST 端点更改为类似的东西

 @RequestMapping(path = "/employees/{employeeId}",produces = {MediaType.APPLICATION_JSON, MediaType.APPLICATION_XML}, consumes = {MediaType.APPLICATION_JSON, MediaType.APPLICATION_XML, MediaType.TEXT_PLAIN})
    public Employee retrievebyId(@PathVariable String employeeId) {
        return employeeService.retrieveEmployee(employeeId);
    }

【讨论】：

当我将 APPLICATION_XML 用于生产 = "" 时，它显示类型不匹配：无法从 MediaType 转换为字符串 []
使用您的原始代码，您可以检查您的 Employee 类是否具有适当的 getter 和 setter。请参阅下面的链接。 stackoverflow.com/questions/28466207/…
我上面有employee.java，我不认为我缺少任何getter或setter
当您将接受标头设置为 XML 时，能否请您发布来自客户端的错误堆栈跟踪？

【解决方案2】：

我发现问题在于我缺少 jackson xml 依赖项。将此添加到 pom.xml

<dependency>
    <groupId>com.fasterxml.jackson.dataformat</groupId>
    <artifactId>jackson-dataformat-xml</artifactId>
</dependency>

【讨论】：