java - 使用 Spring MVC 从存储库检索 XML 元数据

Question

大家好，我现在尝试 7 天从网络存储库中检索数据。特别是我尝试从这里检索作者列表(其 URL:http://www.../base/author):

 <authors xmlns="http:www.../base" xmlns:atom="http://www.w3.org/2005/atom">
  <author> 
      <atom:link rel="author" type="application/xml" href="http://www.../base/author/1"/>
  </author>
  <author>
      <atom:link rel="author" type="application/xml" href="http://www.../base/author/2"/>
  </author>
  <author>
      <atom:link rel="author" type="application/xml" href="http://www.../base/author/3"/>           
  </author>
</authors>

每个作者都来自这里:

<author xmlns="http://http:www.../base" xmlns:atom="http://www.w3.org/2005/atom">
   <name>S. Crocker</name>
   <address>None</address>
   <affiliation></affiliation>
   <email>None</email>
</author>

我的模型类是:

 import javax.xml.bind.annotation.XmlRootElement;

   @XmlRootElement(name="author")
   public class Author {

private Long id;
private String name;
private String address;
private String affiliation;
    private String email;

public Long getId() {
    return id;
}
public void setId(Long id) {
    this.id = id;
}
public String getName() {
    return name;
}
public void setFirstName(String name) {
    this.name = name;
}
public String getAddress() {
    return address;
}
public void setAddress(String address) {
    this.address = address;
}
public String getAffiliation() {
    return affiliation;
}
public void setAffiliation(String affiliation) {
    this.affiliation = affiliation;
}
public String getEmail() {
    return email;
}
public void setEmail(String email) {
    this.email = email;
}

}

还有:

  import java.util.List;

  import javax.xml.bind.annotation.XmlRootElement;

   @XmlRootElement(name="authors")
   public class AuthorList {

private List<Author> data;

public List<Author> getData() {
    return data;
}

public void setData(List<Author> data) {
    this.data = data;
}

}

Controller :

 public class Controller {

 protected static Logger logger = Logger.getLogger("controller");

 private RestTemplate restTemplate = new RestTemplate();

/**
 * Retrieves all records from the REST provider
 * and displays the records in a JSP page
 */
@RequestMapping(value = "/authors", method = RequestMethod.GET)//getall
public String getAll(Model model) {


    // Prepare acceptable media type
    List<MediaType> acceptableMediaTypes = new ArrayList<MediaType>();
    acceptableMediaTypes.add(MediaType.APPLICATION_XML);

    // Prepare header
    HttpHeaders headers = new HttpHeaders();
    headers.setAccept(acceptableMediaTypes);
    HttpEntity<Author> entity = new HttpEntity<Author>(headers);

    // Send the request as GET
    try {
        ResponseEntity<AuthorList> result = restTemplate.exchange("href="http://www.../base/author/", 
                        HttpMethod.GET, entity, AuthorList.class);
        // Add to model
        model.addAttribute("authors", result.getBody().getData());

    } catch (Exception e) {
    }

    // This will resolve to /WEB-INF/jsp/personspage.jsp
    return "personspage";
}

/**
 * Retrieves a single record from the REST provider
 * and displays the result in a JSP page
 */
@RequestMapping(value = "/author", method = RequestMethod.GET)
public String getPerson(@RequestParam("id") Long id, Model model) {


    // Prepare acceptable media type
    List<MediaType> acceptableMediaTypes = new ArrayList<MediaType>();
    acceptableMediaTypes.add(MediaType.APPLICATION_XML);

    // Prepare header
    HttpHeaders headers = new HttpHeaders();
    headers.setAccept(acceptableMediaTypes);
    HttpEntity<Author> entity = new HttpEntity<Author>(headers);

    // Send the request as GET
    try {
        ResponseEntity<Author> result = restTemplate.exchange("href="http://www.../base/author/{id}",
                            HttpMethod.GET, entity, Author.class, id);
        // Add to model
        model.addAttribute("author", result.getBody());

    } catch (Exception e) {
    }

    // This will resolve to /WEB-INF/jsp/getpage.jsp
    return "getpage";
}




}

最后是两个 View 之一，getpage:

  <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
  <%@page contentType="text/html" pageEncoding="UTF-8"%>
   <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
    "http://www.w3.org/TR/html4/loose.dtd">

  <html>
  <head>
 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
 <title>Insert title here</title>
 </head>
 <body>
 <h1>Get Author</h1>

 <c:if test="${empty author}">
 No records found!
 </c:if>

 <c:if test="${!empty author}">
<table style="border: 1px solid #333">
    <tr>
    <td style="width: 100px">Id</td>
    <td>${author.id}</td>
    </tr>

    <tr>
    <td>Name</td>
    <td>${author.name}</td>
    </tr>

    <tr>
    <td>Address</td>
    <td>${author.address}</td>
    </tr>

    <tr>
    <td>Affiliation</td>
    <td>${author.affiliation}</td>
    </tr>

            <tr>
    <td>Email</td>
    <td>${author.email}</td>
    </tr>
</table>
</c:if>

现在，当我运行该程序时，我会看到如下内容:

没有找到记录!

当我给出以下 URL 时: http://localhost:8080/Client_for_rest/author?id=1

我应该从存储库接收数据，姓名电子邮件等但相反我收到了这个:请求的资源 () 不可用。我不明白 URL 之间的映射有什么问题收到的数据？有什么建议吗？

Answer 1

关于您的第一个问题，JAXB注释看起来不正确，authors xml元素没有映射到您的AuthorList类，author内的内部元素author没有映射到Author类，并且命名空间没有被映射已占。

我认为对 JAXB 注释的一些快速修复可能是:您可以定义几个类:原子链接:@XmlAccessorType(XmlAccessType.FIELD)

public class Atomlink {
    @XmlAttribute
    private String rel;
    @XmlAttribute
    private String type;
    @XmlAttribute
    private String href;
    .......

AuthorMeta，代表作者中的作者标签:

@XmlAccessorType(XmlAccessType.FIELD)
public class AuthorMeta {

    @XmlElement(name="link", namespace="http://www.w3.org/2005/atom")
    private Atomlink link;

    public Atomlink getLink() {
        return link;
    }

    public void setLink(Atomlink link) {
        this.link = link;
    }
}

最后是您已经拥有的 AuthorList，但带有 namespace :

@XmlRootElement(name = "authors", namespace="http:www.../base")
@XmlAccessorType(XmlAccessType.FIELD)
public class AuthorList {

    private List<AuthorMeta> author;

    public List<AuthorMeta> getAuthor() {
        return author;
    }

    public void setAuthor(List<AuthorMeta> data) {
        this.author = data;
    }
}

这应该可以解决您无法干净绑定(bind)的第一个问题。

您必须按照相同的方式定义作者结果的绑定(bind):

@XmlRootElement(name = "author", namespace="http://http:www.../base")
@XmlAccessorType(XmlAccessType.FIELD)
public class Author {
    private String name;
    private String address;
    private String affiliation;
    private String email;

现在关于找不到资源的第二个问题..映射看起来不错，最好将日志级别设置为跟踪并查看发生了什么。