Question

好的，我的网络服务有问题。

我正在尝试为用户创建一个API，但在我部署应用程序并尝试获取所有用户之后，它给了我一个例外。

这是我的api课程：

package api;


import java.util.ArrayList;

import javax.ws.rs.Consumes;
import javax.ws.rs.GET;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;

import model.UserManager;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import dto.User;

@Path("/user")
public class UserAPI {

    @POST 
    @Path("create-user/{user}")
    @Consumes(MediaType.APPLICATION_JSON)
    @Produces(MediaType.APPLICATION_JSON)
    public Response saveUser(@PathParam("user") User user) throws JSONException {
        UserManager userManager = new UserManager();
        userManager.createUser(user);

        return Response.status(200).build();    
    }

    @GET
    @Produces(MediaType.APPLICATION_JSON)
    public JSONObject getAllUsers() throws JSONException {
        JSONObject users = null;
        try {
            ArrayList<User> usersList = null;
            UserManager userManager = new UserManager();
            usersList = userManager.getUsers();
            JSONObject usersObject = new JSONObject();
            for(int i = 0; i < usersList.size(); i++) {
                usersObject.put("users", usersList);
            }
            users = usersObject;
        } catch(Exception e) {
            e.printStackTrace();
        }
        return users;   
    }

    @POST 
    @Path("edit-user/{id}")
    @Consumes(MediaType.APPLICATION_JSON)
    @Produces(MediaType.APPLICATION_JSON)
    public Response editUser(@PathParam("id") int id) throws JSONException {
        UserManager userManager = new UserManager();
        userManager.editUser(id);

        return Response.status(200).build();    
    }

    @POST 
    @Path("delete-user/{id}")
    @Consumes(MediaType.APPLICATION_JSON)
    @Produces(MediaType.APPLICATION_JSON)
    public Response deleteUser(@PathParam("id") int id) throws JSONException {
        UserManager userManager = new UserManager();
        userManager.deleteUser(id);

        return Response.status(200).build();    
    }

    @POST 
    @Path("user-login/{user}")
    @Consumes(MediaType.APPLICATION_JSON)
    @Produces(MediaType.APPLICATION_JSON)
    public Response userLogin(@PathParam("user") User user) throws JSONException {
        UserManager userManager = new UserManager();
        userManager.userLogin(user);

        return Response.status(200).build();    
    }
}

以下是错误日志：

javax.servlet.ServletException: Servlet.init() for servlet Jersey REST Service threw exception
    org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    org.apache.catalina.valves.RemoteIpValve.invoke(RemoteIpValve.java:683)
    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
    org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
    org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:314)
    java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    java.lang.Thread.run(Thread.java:745)

com.sun.jersey.spi.inject.Errors$ErrorMessagesException
    com.sun.jersey.spi.inject.Errors.processErrorMessages(Errors.java:170)
    com.sun.jersey.spi.inject.Errors.postProcess(Errors.java:136)
    com.sun.jersey.spi.inject.Errors.processWithErrors(Errors.java:199)
    com.sun.jersey.server.impl.application.WebApplicationImpl.initiate(WebApplicationImpl.java:795)
    com.sun.jersey.server.impl.application.WebApplicationImpl.initiate(WebApplicationImpl.java:790)
    com.sun.jersey.spi.container.servlet.ServletContainer.initiate(ServletContainer.java:491)
    com.sun.jersey.spi.container.servlet.ServletContainer$InternalWebComponent.initiate(ServletContainer.java:321)
    com.sun.jersey.spi.container.servlet.WebComponent.load(WebComponent.java:605)
    com.sun.jersey.spi.container.servlet.WebComponent.init(WebComponent.java:207)
    com.sun.jersey.spi.container.servlet.ServletContainer.init(ServletContainer.java:376)
    com.sun.jersey.spi.container.servlet.ServletContainer.init(ServletContainer.java:559)
    javax.servlet.GenericServlet.init(GenericServlet.java:158)
    org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    org.apache.catalina.valves.RemoteIpValve.invoke(RemoteIpValve.java:683)
    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
    org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
    org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:314)
    java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    java.lang.Thread.run(Thread.java:745)

Answer 1

为什么不按原样返回用户列表而不是将其转换为json对象？试试这个：

@GET
@Produces(MediaType.APPLICATION_JSON)
public List<User> getAllUsers() {
    JSONObject users = null;
    try {
        ArrayList<User> usersList = null;
        UserManager userManager = new UserManager();
        usersList = userManager.getUsers();
    } catch(Exception e) {
        e.printStackTrace();
    }
    return usersList;   
}

要从您的视图调用上述方法，您可以使用以下jquery ajax调用：

$.ajax({
type: "GET",
url: "http://localhost:8080/YourProjectName/rest/user",
dataType: "json",
success: function(jsonString) {
   alert(jsonString);
},
error: function(xhr) {                     
    alert(JSON.stringify(xhr));
}

}）;

如果它仍然不起作用，那么它可能是您正在使用的一组库的问题。因此，我建议您使用GlassFish 4.0应用程序服务器而不是Tomcat服务器。如果您使用GlassFish服务器，则不得在类路径中包含任何球衣jar，因为GlassFish服务器本身具有所有与球衣相关的jar。

Answer 2

首先，您要将User对象作为PathParam提交。这不起作用！
另外我想建议你，让UserManager成为单身人士比，你应该使用GET，PUT，POST，DELETE而不仅仅是GET和POST

我认为例外情况表明你在web.xml中犯了一个错误，并且球衣无法找到（或任何）@Path。因此，请给我们web.xml来证明这一点，并且你也可以通过pom.xml来检查它。

顺便说一句，泽西带来（联合国）marshallers，没有看到使用JSONObject的理由。

这里有些东西：

简单的web.xml

<?xml version="1.0" encoding="UTF-8"?>
    <!-- not required with servlet 3.x -->
    <web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
    <servlet>
        <servlet-name>REST</servlet-name>
        <servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
        <init-param>
            <param-name>javax.ws.rs.Application</param-name>
            <param-value>path.to.ResourceConfigOrApplication</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>REST</servlet-name>
        <url-pattern>/*</url-pattern>
    </servlet-mapping>
</web-app>

pom.xml（部分）

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.plugin.version>2.5.1</maven.compiler.plugin.version>
    <tomcat7.version>2.1</tomcat7.version>
    <jersey.version>2.12</jersey.version>
</properties>
<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>
    <!-- JERSEY -->
    <dependency>
        <groupId>org.glassfish.jersey.core</groupId>
        <artifactId>jersey-server</artifactId>
    </dependency>
    <dependency>
        <groupId>org.glassfish.jersey.bundles</groupId>
        <artifactId>jaxrs-ri</artifactId>
    </dependency>
    <dependency>
        <groupId>org.glassfish.jersey.containers</groupId>
        <artifactId>jersey-container-servlet</artifactId>
    </dependency>
    <dependency>
        <groupId>org.glassfish.jersey.media</groupId>
        <artifactId>jersey-media-json-processing</artifactId>
    </dependency>
    <dependency>
        <groupId>org.glassfish.jersey.media</groupId>
        <artifactId>jersey-media-json-jackson</artifactId>
    </dependency>
    <dependency>
        <groupId>org.glassfish.jersey.media</groupId>
        <artifactId>jersey-media-multipart</artifactId>
    </dependency>
    <dependency>
        <groupId>org.glassfish.jersey.media</groupId>
        <artifactId>jersey-media-moxy</artifactId>
    </dependency> 
    // ...

非常简单的用户：

@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
public class User implements Serializable {

    private static final long serialVersionUID = 1L;

    @XmlElement(name="id")
    private Integer id;

    @XmlElement(name="username")
    private String username;

    // ...
}

简单的资源（基于你的）：

@Path("/users") // changed from user to users 
public class UserAPI {

    @POST 
    @Consumes(MediaType.APPLICATION_JSON)
    @Produces(MediaType.APPLICATION_JSON)
    public Response saveUser(User user) {
        user = UserManager.getInstance().createUser(user);
        return Response.ok(user).build();    
    }

    @GET
    @Produces(MediaType.APPLICATION_JSON)
    public Response getAllUsers() {
        List<User> users = UserManager.getInstance().getUsers();
        GenericEntity<List<User>> entity = new GenericEntity<List<User>>(
            users
        ){};
        return Response.ok( entity ).build();
    }

    @PUT // edit-user -> PUT 
    @Path("/{id}")
    @Consumes(MediaType.APPLICATION_JSON)
    @Produces(MediaType.APPLICATION_JSON)
    public Response editUser(@PathParam("id") Integer id, User user) {
        user = UserManager.getInstance().editUser(id, user); // check id and uder.id, if user exists etc
        return Response.ok(user).build();
    }

    @DELETE // delete-user -> DELETE
    @Path("/{id}")
    @Produces(MediaType.APPLICATION_JSON)
    public Response deleteUser(@PathParam("id") Integer id) {
        UserManager.getInstance().deleteUser(id);
        return Response.ok().build();    
    }
}

Jersey Web服务提供javax.servlet.ServletException：

2 个答案: