Question

很久以前我已经开发了一个RESTFUL Web服务的教程。现在我已经在我的eclipse中导入了同一个项目，但我不记得我之前如何运行这个项目。我想知道更多关于POM.XML和其他依赖项的重要性。

1.是否有必要使用Maven构建来构建项目？这将给出pom.xml

2.如果是，pom.xml是我们定义依赖项的地方吗？像jars需要读取一些excel文件？这是我可以定义依赖的相同位置，它将自动下载。

3.我真的需要一个maven构建吗？我有简单的课程和DAO和BEAN。

import java.io.IOException;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.QueryParam;
import javax.ws.rs.core.MediaType;

import Bean.bookBean;
import Dao.bookDao;
@Path ("login")
public class bookPost {

@GET
@Path("validate")
@Produces(MediaType.TEXT_PLAIN)
    public String login(@QueryParam("frition")String un,@QueryParam("thriller")String pwd) throws IOException
{
    bookDao dao=new bookDao();
    bookBean tt=new bookBean();
    tt.setFrition(un);
    tt.setThriller(pwd);

    return dao.loginValidate(tt);
    }
}

我的bookCategory类

import javax.ws.rs.core.UriBuilder;
import com.sun.jersey.api.client.Client;
import com.sun.jersey.api.client.WebResource;
import com.sun.jersey.api.client.config.ClientConfig;
import com.sun.jersey.api.client.config.DefaultClientConfig;
import Bean.bookBean;
import java.io.File;
import java.io.IOException;
import java.net.URI;
import jxl.Cell;
import jxl.CellType;
import jxl.Sheet;
import jxl.Workbook;
import jxl.read.biff.BiffException;

    public class BookCategories {

        private String inputFile;
        public void setInputFile(String inputFile) {
            this.inputFile = inputFile;
        }

        public void read() throws IOException  {
            File inputWorkbook = new File(inputFile);
            Workbook w;
            try {
                w = Workbook.getWorkbook(inputWorkbook);
                // Get the first sheet
                Sheet sheet = w.getSheet(0);
                // Loop over first 10 column and lines

                for (int j = 0; j < sheet.getColumns(); j++) {
                    for (int i = 0; i < sheet.getRows(); i++) {
                        Cell cell = sheet.getCell(j, i);
                        CellType type = cell.getType();

                        if (cell.getType() == CellType.LABEL) {
                            System.out.println("books "
                                    + cell.getContents());
                        }
            }
                }
            } catch (BiffException e) {
                e.printStackTrace();
            }



        }

        public static void main(String[] args) throws IOException {
            ClientConfig config = new DefaultClientConfig();
            Client client = Client.create(config);
            WebResource service = client.resource(getBaseURI());
            // Fluent interfaces
            bookBean lbean = new bookBean();
            lbean.setFrition("frition");
            lbean.setThriller("thriller");
            String cr =service.path("login").path("postvalidate").post(String.class,lbean);
            System.out.println(cr);
}

private static URI getBaseURI() {
    return UriBuilder.fromUri("http://localhost:8080/Services").build();
}

        }

4.我们真的需要POM.XML吗？到目前为止，它显示了poi jar的错误。我已手动下载它们并将文件也添加到项目中。如果我在APACHE TOMCAT 7服务器上运行该项目，则控制台中会出现以下错误。

Error May 13, 2014 2:44:05 PM com.sun.jersey.api.core.servlet.WebAppResourceConfig init
INFO: Scanning for root resource and provider classes in the Web app resource paths:
  /WEB-INF/lib
  /WEB-INF/classes
May 13, 2014 2:44:06 PM com.sun.jersey.api.core.ScanningResourceConfig init
INFO: No root resource classes found.
May 13, 2014 2:44:06 PM com.sun.jersey.api.core.ScanningResourceConfig logClasses
INFO: Provider classes found:
  class org.codehaus.jackson.jaxrs.JacksonJaxbJsonProvider
  class org.codehaus.jackson.jaxrs.JacksonJsonProvider
  class org.codehaus.jackson.jaxrs.JsonMappingExceptionMapper
  class org.codehaus.jackson.jaxrs.JsonParseExceptionMapper
May 13, 2014 2:44:06 PM com.sun.jersey.server.impl.application.WebApplicationImpl _initiate
INFO: Initiating Jersey application, version 'Jersey: 1.12 02/15/2012 04:51 PM'
May 13, 2014 2:44:06 PM com.sun.jersey.server.impl.application.RootResourceUriRules <init>
SEVERE: The ResourceConfig instance does not contain any root resource classes.
May 13, 2014 2:44:06 PM org.apache.catalina.core.ApplicationContext log
SEVERE: StandardWrapper.Throwable
com.sun.jersey.api.container.ContainerException: The ResourceConfig instance does not contain any root resource classes.
    at com.sun.jersey.server.impl.application.RootResourceUriRules.<init>(RootResourceUriRules.java:99)
    at com.sun.jersey.server.impl.application.WebApplicationImpl._initiate(WebApplicationImpl.java:1308)
    at com.sun.jersey.server.impl.application.WebApplicationImpl.access$700(WebApplicationImpl.java:171)
    at com.sun.jersey.server.impl.application.WebApplicationImpl$13.f(WebApplicationImpl.java:777)
    at com.sun.jersey.server.impl.application.WebApplicationImpl$13.f(WebApplicationImpl.java:773)
    at com.sun.jersey.spi.inject.Errors.processWithErrors(Errors.java:193)
    at com.sun.jersey.server.impl.application.WebApplicationImpl.initiate(WebApplicationImpl.java:773)
    at com.sun.jersey.server.impl.application.WebApplicationImpl.initiate(WebApplicationImpl.java:768)
    at com.sun.jersey.spi.container.servlet.ServletContainer.initiate(ServletContainer.java:488)
    at com.sun.jersey.spi.container.servlet.ServletContainer$InternalWebComponent.initiate(ServletContainer.java:318)
    at com.sun.jersey.spi.container.servlet.WebComponent.load(WebComponent.java:607)
    at com.sun.jersey.spi.container.servlet.WebComponent.init(WebComponent.java:208)
    at com.sun.jersey.spi.container.servlet.ServletContainer.init(ServletContainer.java:373)
    at com.sun.jersey.spi.container.servlet.ServletContainer.init(ServletContainer.java:556)
    at javax.servlet.GenericServlet.init(GenericServlet.java:160)
    at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1133)
    at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1087)
    at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:799)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:135)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:161)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:541)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:383)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:243)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:188)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:166)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:288)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)

May 13, 2014 2:44:06 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Allocate exception for servlet Ebook
com.sun.jersey.api.container.ContainerException: The ResourceConfig instance does not contain any root resource classes.
    at com.sun.jersey.server.impl.application.RootResourceUriRules.<init>(RootResourceUriRules.java:99)
    at com.sun.jersey.server.impl.application.WebApplicationImpl._initiate(WebApplicationImpl.java:1308)
    at com.sun.jersey.server.impl.application.WebApplicationImpl.access$700(WebApplicationImpl.java:171)
    at com.sun.jersey.server.impl.application.WebApplicationImpl$13.f(WebApplicationImpl.java:777)
    at com.sun.jersey.server.impl.application.WebApplicationImpl$13.f(WebApplicationImpl.java:773)
    at com.sun.jersey.spi.inject.Errors.processWithErrors(Errors.java:193)
    at com.sun.jersey.server.impl.application.WebApplicationImpl.initiate(WebApplicationImpl.java:773)
    at com.sun.jersey.server.impl.application.WebApplicationImpl.initiate(WebApplicationImpl.java:768)
    at com.sun.jersey.spi.container.servlet.ServletContainer.initiate(ServletContainer.java:488)
    at com.sun.jersey.spi.container.servlet.ServletContainer$InternalWebComponent.initiate(ServletContainer.java:318)
    at com.sun.jersey.spi.container.servlet.WebComponent.load(WebComponent.java:607)
    at com.sun.jersey.spi.container.servlet.WebComponent.init(WebComponent.java:208)
    at com.sun.jersey.spi.container.servlet.ServletContainer.init(ServletContainer.java:373)
    at com.sun.jersey.spi.container.servlet.ServletContainer.init(ServletContainer.java:556)
    at javax.servlet.GenericServlet.init(GenericServlet.java:160)
    at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1133)
    at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1087)
    at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:799)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:135)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:161)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:541)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:383)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:243)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:188)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:166)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:288)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)

我试图在其他论坛上找到这个。但我只是迷失在中间，因为我心中有很多问题。大约4个小时但没有继续前进。希望获得清晰明快的信息。

Answer 1

经过一段时间的研究和几天脑力激荡与MAVEN。我能够自己回答我的问题。

1. No it is not a compulsion to build a project using maven build or ant build or any other build.But if you are using MAVEN it will definitely have pom.xml where you will be defining dependencies,details of packaging the JAR's.

构建过程通常意味着它将从您编写的源文件开始，最终以jar或war的形式结束，可以部署在服务器上。

2. Yes you can define the compile time and run time dependencies.If you want to know about [compile time and run time dependencies](http://stackoverflow.com/questions/4270950/compile-time-vs-run-time-dependency-java).And yes it also provide you the feature to download the required jars when you will be building the jar in a different machine then yours using that pom.xml.

3. If you want to package it in jar and define dependency you need MAVEN.Else you do not need maven build for this.

依赖关系和图书馆（JAR）下载，概念

1 个答案: