在泽西岛找不到资源（错误404）

I am making an AJAX call to a Jersey resource through JavaScript where class is mapped to /books and a GET method to /allBooks. This is the code for AJAX call:

我正在通过JavaScript对Jersey资源进行AJAX调用,其中类映射到/ books,GET方法映射到/ allBooks。这是AJAX调用的代码:

function libBooks(){

    alert("Inside js");
    //The above alert is displayed

    var requestData = {
            "dataType":  "application/json",
            "type":   "GET",
            "url":    "http://localhost:8080/library/rest/books/allBooks/"
    };

    var request = $.ajax(requestData);
    alert("Ajax call made");
    //The above alert is displayed

    request.success(function(data) {

        alert("Inside done function");
        //The above alert is not displayed
        var dataReceived =data.listOfBooks;
        var numOfItems = dataReceived.length;
        alert(numOfItems);

    });

    request.fail(function(jqXHR, status, errorMessage) {
        if((errorMessage = $.trim(errorMessage)) === "") {
            alert("An unspecified error occurred.  Check the server error log for details.");
        }
        else {
            alert("An error occurred:  " + errorMessage);
        }
    });

}

In JSP I have a link like this:

在JSP中我有这样的链接:

<p>List of books in library  <a href="" onclick="libBooks();">Click Here</a></p>

And here is my BookResource:

这是我的BookResource:

@Path("/books")
public class BookResource {

    @GET
    @Path("/allBooks")
    @Produces(MediaType.APPLICATION_JSON)
    public Response getAllBooks() {

        BooksHelper bookHelper = new BooksHelper();
        ArrayList<Book> listOfBooks = bookHelper.getListOfBooks();

        ResponseBuilder responseBuilder = Response.status(Status.OK);
        responseBuilder.entity(listOfBooks);

        Response response = responseBuilder.build();
        return response;            
    }
}

Here is my pom.xml

这是我的pom.xml

<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/maven-v4_0_0.xsd">

    <modelVersion>4.0.0</modelVersion>

    <groupId>org.sudhanshu</groupId>
    <artifactId>library</artifactId>
    <packaging>war</packaging>
    <version>0.0.1-SNAPSHOT</version>
    <name>library</name>

    <build>
        <finalName>library</finalName>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>2.5.1</version>
                <inherited>true</inherited>
                <configuration>
                    <source>1.7</source>
                    <target>1.7</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.glassfish.jersey</groupId>
                <artifactId>jersey-bom</artifactId>
                <version>${jersey.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <dependencies>
        <dependency>
            <groupId>org.glassfish.jersey.containers</groupId>
            <artifactId>jersey-container-servlet-core</artifactId>
            <!-- use the following artifactId if you don't need servlet 2.x compatibility -->
            <!-- artifactId>jersey-container-servlet</artifactId -->
        </dependency>
        <!-- uncomment this to get JSON support
        <dependency>
            <groupId>org.glassfish.jersey.media</groupId>
            <artifactId>jersey-media-moxy</artifactId>
        </dependency>
        -->
      <dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>jstl</artifactId>
    <version>1.2</version>
</dependency>

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.6</version>
</dependency>

    </dependencies>
    <properties>
        <jersey.version>2.16</jersey.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>
</project>

I am not sure how mapping in pom.xml works as I am using Maven for the first time. Here is my web.xml:

我不确定pom.xml中的映射是如何工作的,因为我第一次使用Maven。这是我的web.xml:

<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" version="2.5">
  <servlet>
    <servlet-name>Jersey Web Application</servlet-name>
    <servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
    <init-param>
      <param-name>jersey.config.server.provider.packages</param-name>
      <param-value>org.sudhanshu.library</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
  </servlet>

  <servlet-mapping>
    <servlet-name>Jersey Web Application</servlet-name>
    <url-pattern>/rest/*</url-pattern>
  </servlet-mapping>
</web-app>

When I get to the URL: http://localhost:8080/library/rest/books/allBooks , it says resource not found 404. I think the problem might be in web.xml REST request entry point and my mapping in Resource. Also, please suggest if URL in my ajax request is correct or not. I have tried various things but none of them are working. For now I just want an alert that shows that ajax call was successful.Here is my directory structure: Any help will be appreciated. Thank You.

当我到达URL:http:// localhost:8080 / library / rest / books / allBooks时,它说资源找不到404.我认为问题可能出在web.xml REST请求入口点和我在Resource中的映射。另外,请建议我的ajax请求中的URL是否正确。我尝试了各种各样的东西,但没有一个在起作用。现在我只想要一个警告,显示ajax调用成功。这是我的目录结构:任何帮助将不胜感激。谢谢。

2 个解决方案

#1

Look at here

看看这里

<init-param>
  <param-name>jersey.config.server.provider.packages</param-name>
  <param-value>org.sudhanshu.library</param-value>
</init-param>

You're specifying the package(s) to scan is org.sudhanshu.library. Looking at the image of your project structure, that package is empty. The package you should be scanning is com.resources

您要指定要扫描的包是org.sudhanshu.library。查看项目结构的图像,该包是空的。您应该扫描的包是com.resources

Second thing (unrelated to the 404, but will be the next problem) is you need a JSON provider. You can see in the generated pom.xml file they give you a hint

第二件事(与404无关,但将成为下一个问题)是你需要一个JSON提供者。您可以在生成的pom.xml文件中看到它们为您提供的提示

<!-- uncomment this to get JSON support
<dependency>
    <groupId>org.glassfish.jersey.media</groupId>
    <artifactId>jersey-media-moxy</artifactId>
</dependency>
-->

You need to un-comment that dependency. Also I would change the dependency from jersey-media-moxy to jersey-media-json-jackson. IMO Jackson works a lot better than MOXy in many aspects.

您需要取消注释该依赖项。此外,我会将依赖从jersey-media-moxy更改为jersey-media-json-jackson。 IMO Jackson在许多方面比MOXy做得更好。

#2

This helped me find out what was my problem: I was having the same issue (resource not found) and I tried to establish my <param-value> tag with only the name of the package where my resource is (not nameOfMyApp.myResource). I think it could be helpful to know it as few colleagues where having also the same mistake as I was.

这有助于我找出我的问题:我遇到了同样的问题(资源未找到),我试图建立我的 标签,只包含我的资源所在的包的名称(不是nameOfMyApp.myResource) 。我认为知道它可能会有所帮助,因为很少有同事和我一样犯同样的错误。