REST Webserivce在数据库更改后不会更新

Question

大家好，我正在尝试使用REST Webservice与数据库进行通信。 对于这个项目，我使用Netbeans 8.1，Struts 1.3和REST Webservice，编程语言是Java。

我有一个更大的项目，我正在处理，并且存在问题。它不会在运行时识别数据库中的更改。
数据库中有一张名为'cardreader'的表格和一张名为'chipcards'的表格。读卡器有一个ID，芯片卡ID为外键和时间戳。芯片卡有一个ID，一个权限ID，一个校验和和一个时间戳。

读卡器：

+----------------+---------+-------------------------+ 
| reader_id  | card_id | ts_lastupdate   | 
+----------------+---------+-------------------------+ 
| 192.168.178.21 | 1004 | 2015-02-08 20:14:25.401 | 
+----------------+---------+-------------------------+ 

芯片卡：

+------+---------------+----------------+-------------------------+ 
| id | permission_id | checksum  | ts_lastupdate   | 
+------+---------------+----------------+-------------------------+ 
| 1002 |    1 | 20141106142003 | 2015-01-22 22:02:50.956 | 
| 1003 |    1 | 20141022002939 | 2015-01-22 22:03:00.469 | 
| 1004 |    1 | 20141022210457 | 2015-01-22 22:03:13.108 | 
| 1005 |    2 | 20141022002737 | 2015-01-22 22:03:17.336 | 
| 1006 |    1 | 20141022002736 | 2015-01-22 22:03:25.968 | 
| 1007 |    3 | 20141029163510 | 2015-01-22 22:03:29.645 | 
+------+---------------+----------------+-------------------------+ 

在我的计划，我可以进入 'reader_id'，然后在数据库中查找。如果找到reader_id，我将找回存储'card_id'的Cardreader对象。
问题是，如果我启动程序并输入readerid，我会找回匹配的芯片卡，但是如果我然后在数据库中更改cardreader表中的'card_id'（假设为1002），程序仍会返回1004.
正如在乞讨中提到的，我使用REST Webservices和Netbeans。借助Netbeans，您可以生成“从数据库获取REST风格的Web服务”，并从FacadeREST类生成“Java Jersey客户端”。

在这里，你可以看一下类
AbstractFacade

/* 
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* To change this template file, choose Tools | Templates 
* and open the template in the editor. 
*/ 
package com.accounting.service; 

import java.util.List; 
import javax.persistence.EntityManager; 

/** 
* 
* @author Tobias 
*/ 
public abstract class AbstractFacade<T> { 
    private Class<T> entityClass; 

    public AbstractFacade(Class<T> entityClass) { 
     this.entityClass = entityClass; 
    } 

    protected abstract EntityManager getEntityManager(); 

    public void create(T entity) { 
     getEntityManager().persist(entity); 
    } 

    public void edit(T entity) { 
     getEntityManager().merge(entity); 
    } 

    public void remove(T entity) { 
     getEntityManager().remove(getEntityManager().merge(entity)); 
    } 

    public T find(Object id) { 
     return getEntityManager().find(entityClass, id); 
    } 

    public List<T> findAll() { 
     javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery(); 
     cq.select(cq.from(entityClass)); 
     return getEntityManager().createQuery(cq).getResultList(); 
    } 

    public List<T> findRange(int[] range) { 
     javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery(); 
     cq.select(cq.from(entityClass)); 
     javax.persistence.Query q = getEntityManager().createQuery(cq); 
     q.setMaxResults(range[1] - range[0] + 1); 
     q.setFirstResult(range[0]); 
     return q.getResultList(); 
    } 

    public int count() { 
     javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery(); 
     javax.persistence.criteria.Root<T> rt = cq.from(entityClass); 
     cq.select(getEntityManager().getCriteriaBuilder().count(rt)); 
     javax.persistence.Query q = getEntityManager().createQuery(cq); 
     return ((Long) q.getSingleResult()).intValue(); 
    } 

} 

CardreaderFacade

/* 
* To change this license header, choose License Headers in Project Properties. 
* To change this template file, choose Tools | Templates 
* and open the template in the editor. 
*/ 
package com.accounting.service; 

import com.accounting.Cardreader; 
import java.util.List; 
import javax.persistence.EntityManager; 
import javax.persistence.Persistence; 
import javax.persistence.PersistenceContext; 
import javax.ws.rs.Consumes; 
import javax.ws.rs.DELETE; 
import javax.ws.rs.GET; 
import javax.ws.rs.POST; 
import javax.ws.rs.PUT; 
import javax.ws.rs.Path; 
import javax.ws.rs.PathParam; 
import javax.ws.rs.Produces; 

/** 
* 
* @author Tobias 
*/ 
@javax.ejb.Stateless 
@Path("com.accounting.cardreader") 
public class CardreaderFacadeREST extends AbstractFacade<Cardreader> { 
    @PersistenceContext(unitName = "WebApplication1PU") 
    private EntityManager em = Persistence.createEntityManagerFactory("WebApplication1PU").createEntityManager(); 

    public CardreaderFacadeREST() { 
     super(Cardreader.class); 
    } 

    @POST 
    @Override 
    @Consumes({"application/xml", "application/json"}) 
    public void create(Cardreader entity) { 
     super.create(entity); 
    } 

    @PUT 
    @Path("{id}") 
    @Consumes({"application/xml", "application/json"}) 
    public void edit(@PathParam("id") String id, Cardreader entity) { 
     super.edit(entity); 
    } 

    @DELETE 
    @Path("{id}") 
    public void remove(@PathParam("id") String id) { 
     super.remove(super.find(id)); 
    } 

    @GET 
    @Path("{id}") 
    @Produces({"application/xml", "application/json"}) 
    public Cardreader find(@PathParam("id") String id) { 
     return super.find(id); 
    } 

    @GET 
    @Override 
    @Produces({"application/xml", "application/json"}) 
    public List<Cardreader> findAll() { 
     return super.findAll(); 
    } 

    @GET 
    @Path("{from}/{to}") 
    @Produces({"application/xml", "application/json"}) 
    public List<Cardreader> findRange(@PathParam("from") Integer from, @PathParam("to") Integer to) { 
     return super.findRange(new int[]{from, to}); 
    } 

    @GET 
    @Path("count") 
    @Produces("text/plain") 
    public String countREST() { 
     return String.valueOf(super.count()); 
    } 

    @Override 
    protected EntityManager getEntityManager() { 
     return em; 
    } 

} 

CardreaderJerseyClient

/* 
* To change this license header, choose License Headers in Project Properties. 
* To change this template file, choose Tools | Templates 
* and open the template in the editor. 
*/ 
package com.accountng.client; 

import javax.ws.rs.ClientErrorException; 
import javax.ws.rs.client.Client; 
import javax.ws.rs.client.WebTarget; 

/** 
* Jersey REST client generated for REST resource:CardreaderFacadeREST 
* [com.accounting.cardreader]<br> 
* USAGE: 
* <pre> 
*  CardreaderJerseyClient client = new CardreaderJerseyClient(); 
*  Object response = client.XXX(...); 
*  // do whatever with response 
*  client.close(); 
* </pre> 
* 
* @author Tobias 
*/ 
public class CardreaderJerseyClient { 
    private WebTarget webTarget; 
    private Client client; 
    private static final String BASE_URI = "http://localhost:8081/WebApplication1/webresources"; 

    public CardreaderJerseyClient() { 
     client = javax.ws.rs.client.ClientBuilder.newClient(); 
     webTarget = client.target(BASE_URI).path("com.accounting.cardreader"); 
    } 

    public String countREST() throws ClientErrorException { 
     WebTarget resource = webTarget; 
     resource = resource.path("count"); 
     return resource.request(javax.ws.rs.core.MediaType.TEXT_PLAIN).get(String.class); 
    } 

    public void edit_XML(Object requestEntity, String id) throws ClientErrorException { 
     webTarget.path(java.text.MessageFormat.format("{0}", new Object[]{id})).request(javax.ws.rs.core.MediaType.APPLICATION_XML).put(javax.ws.rs.client.Entity.entity(requestEntity, javax.ws.rs.core.MediaType.APPLICATION_XML)); 
    } 

    public void edit_JSON(Object requestEntity, String id) throws ClientErrorException { 
     webTarget.path(java.text.MessageFormat.format("{0}", new Object[]{id})).request(javax.ws.rs.core.MediaType.APPLICATION_JSON).put(javax.ws.rs.client.Entity.entity(requestEntity, javax.ws.rs.core.MediaType.APPLICATION_JSON)); 
    } 

    public <T> T find_XML(Class<T> responseType, String id) throws ClientErrorException { 
     WebTarget resource = webTarget; 
     resource = resource.path(java.text.MessageFormat.format("{0}", new Object[]{id})); 
     return resource.request(javax.ws.rs.core.MediaType.APPLICATION_XML).get(responseType); 
    } 

    public <T> T find_JSON(Class<T> responseType, String id) throws ClientErrorException { 
     WebTarget resource = webTarget; 
     resource = resource.path(java.text.MessageFormat.format("{0}", new Object[]{id})); 
     return resource.request(javax.ws.rs.core.MediaType.APPLICATION_JSON).get(responseType); 
    } 

    public <T> T findRange_XML(Class<T> responseType, String from, String to) throws ClientErrorException { 
     WebTarget resource = webTarget; 
     resource = resource.path(java.text.MessageFormat.format("{0}/{1}", new Object[]{from, to})); 
     return resource.request(javax.ws.rs.core.MediaType.APPLICATION_XML).get(responseType); 
    } 

    public <T> T findRange_JSON(Class<T> responseType, String from, String to) throws ClientErrorException { 
     WebTarget resource = webTarget; 
     resource = resource.path(java.text.MessageFormat.format("{0}/{1}", new Object[]{from, to})); 
     return resource.request(javax.ws.rs.core.MediaType.APPLICATION_JSON).get(responseType); 
    } 

    public void create_XML(Object requestEntity) throws ClientErrorException { 
     webTarget.request(javax.ws.rs.core.MediaType.APPLICATION_XML).post(javax.ws.rs.client.Entity.entity(requestEntity, javax.ws.rs.core.MediaType.APPLICATION_XML)); 
    } 

    public void create_JSON(Object requestEntity) throws ClientErrorException { 
     webTarget.request(javax.ws.rs.core.MediaType.APPLICATION_JSON).post(javax.ws.rs.client.Entity.entity(requestEntity, javax.ws.rs.core.MediaType.APPLICATION_JSON)); 
    } 

    public <T> T findAll_XML(Class<T> responseType) throws ClientErrorException { 
     WebTarget resource = webTarget; 
     return resource.request(javax.ws.rs.core.MediaType.APPLICATION_XML).get(responseType); 
    } 

    public <T> T findAll_JSON(Class<T> responseType) throws ClientErrorException { 
     WebTarget resource = webTarget; 
     return resource.request(javax.ws.rs.core.MediaType.APPLICATION_JSON).get(responseType); 
    } 

    public void remove(String id) throws ClientErrorException { 
     webTarget.path(java.text.MessageFormat.format("{0}", new Object[]{id})).request().delete(); 
    } 

    public void close() { 
     client.close(); 
    } 

} 

层

的index.jsp

<%@page contentType="text/html"%> 
    <%@page pageEncoding="UTF-8"%> 

    <%@ taglib uri="http://struts.apache.org/tags-bean" prefix="bean" %> 
    <%@ taglib uri="http://struts.apache.org/tags-html" prefix="html" %> 
    <%@ taglib uri="http://struts.apache.org/tags-logic" prefix="logic"%> 

    <html:form action="/checkCard"> 
     <html:text property="name" value="192.168.178.21">Cardreader IP</html:text> 
     <html:submit property="submitValue">SEND</html:submit> 
    </html:form> 

**checkCard** 

    /* 
    * To change this license header, choose License Headers in Project Properties. 
    * To change this template file, choose Tools | Templates 
    * and open the template in the editor. 
    */ 
    package com.tobias.actions; 

    import com.accounting.Cardreader; 
    import com.accounting.Chipcards; 
    import com.accountng.client.CardreaderJerseyClient; 
    import com.tobias.beans.infoBean; 
    import javax.servlet.http.HttpServletRequest; 
    import javax.servlet.http.HttpServletResponse; 
    import org.apache.struts.action.ActionForm; 
    import org.apache.struts.action.ActionForward; 
    import org.apache.struts.action.ActionMapping; 

    /** 
    * 
    * @author Tobias 
    */ 
    public class checkCard extends org.apache.struts.action.Action { 

     /* forward name="success" path="" */ 
     private static final String SUCCESS = "success"; 

     /** 
     * This is the action called from the Struts framework. 
     * 
     * @param mapping The ActionMapping used to select this instance. 
     * @param form The optional ActionForm bean for this request. 
     * @param request The HTTP Request we are processing. 
     * @param response The HTTP Response we are processing. 
     * @throws java.lang.Exception 
     * @return 
     */ 
     @Override 
     public ActionForward execute(ActionMapping mapping, ActionForm form, 
       HttpServletRequest request, HttpServletResponse response) 
       throws Exception { 

      String readerIP; 
      infoBean formBean = (infoBean) form; 
      readerIP = formBean.getName(); 
      System.out.println("READER IP: " + readerIP); 

      CardreaderJerseyClient cjc = new CardreaderJerseyClient(); 
      if(cjc == null){ 
       System.out.println("JERSEYCLIENT IST NULL"); 
      } 
      Cardreader reader = cjc.find_XML(Cardreader.class, readerIP); 
      if(reader != null){ 
       System.out.println("READER IP = " + reader.getReaderId()); 

       Chipcards card = reader.getCardId(); 
       if(card != null){ 
        System.out.println("CHIPCARD ID = " + card.getId().toString()); 
       } else { 
        System.out.println("No card found); 
       } 
      } else { 
       System.out.println("No reader found"); 
      } 


      return mapping.findForward(SUCCESS); 
     } 
    } 

的struts-config

<?xml version="1.0" encoding="UTF-8" ?> 

<!DOCTYPE struts-config PUBLIC 
      "-//Apache Software Foundation//DTD Struts Configuration 1.3//EN" 
      "http://jakarta.apache.org/struts/dtds/struts-config_1_3.dtd"> 


<struts-config> 
    <form-beans> 
     <form-bean name="infoBean" type="com.tobias.beans.infoBean"/> 

    </form-beans> 

    <global-exceptions> 

    </global-exceptions> 

    <action-mappings> 
     <action name="infoBean" path="/checkCard" scope="request" type="com.tobias.actions.checkCard" validate="false"> 
      <forward name="success" path="/index.jsp"/> 
     </action> 
     <action path="/Welcome" forward="/welcomeStruts.jsp"/> 
    </action-mappings> 

    <controller processorClass="org.apache.struts.tiles.TilesRequestProcessor"/> 

    <message-resources parameter="com/myapp/struts/ApplicationResource"/>  

    <!-- ========================= Tiles plugin ===============================--> 
    <!-- 
    This plugin initialize Tiles definition factory. This later can takes some 
    parameters explained here after. The plugin first read parameters from 
    web.xml, thenoverload them with parameters defined here. All parameters 
    are optional. 
    The plugin should be declared in each struts-config file. 
    - definitions-config: (optional) 
    Specify configuration file names. There can be several comma 
    separated file names (default: ??) 
    - moduleAware: (optional - struts1.1) 
    Specify if the Tiles definition factory is module aware. If true 
    (default), there will be one factory for each Struts module. 
    If false, there will be one common factory for all module. In this 
    later case, it is still needed to declare one plugin per module. 
    The factory will be initialized with parameters found in the first 
    initialized plugin (generally the one associated with the default 
    module). 
    true : One factory per module. (default) 
    false : one single shared factory for all modules 
    - definitions-parser-validate: (optional) 
    Specify if xml parser should validate the Tiles configuration file. 
    true : validate. DTD should be specified in file header (default) 
    false : no validation 

    Paths found in Tiles definitions are relative to the main context. 
    --> 
    <plug-in className="org.apache.struts.tiles.TilesPlugin" > 
     <set-property property="definitions-config" value="/WEB-INF/tiles-defs.xml" />  
     <set-property property="moduleAware" value="true" /> 
    </plug-in> 

    <!-- ========================= Validator plugin ================================= --> 
    <plug-in className="org.apache.struts.validator.ValidatorPlugIn"> 
     <set-property 
      property="pathnames" 
      value="/WEB-INF/validator-rules.xml,/WEB-INF/validation.xml"/> 
    </plug-in> 

</struts-config> 

后记
如果你还在读书：谢谢！我知道我已经发布了很多代码，我不确定我的描述是否足够了解所有内容，但我是德语，请耐心等待。
我对这个REST的东西有一些小的知识，但我还不完全理解最新的情况。总结起来，我不明白为什么我的程序读取数据库的第一个card_id表单正确，但是当我手动更改数据库中的值并且程序仍在运行时，它不会更新。

再次感谢您通过这段文字的读者。如果你有任何想法可能是，或者如果您需要进一步的解释只是让我知道:)

编辑
好于我已经注意到一些更多的信息。该计划还有能力创建预订。因此，客户可以购买一些东西或在他的芯片卡上添加资金。因此，有一张名为“预订”的表格，其中存储了ID，客户ID，价格和bookingtyp。
我已经开始了我的计划，让它读取所有预订并创建300美元的当前预算。如果我离开我的程序并手动添加一个条目到预订表中，然后让我的程序再次读取预订表，数量会增加/减少。但是，如果我现在改变其中一个价格并让程序再次读取所有未更新的预订。
因此，在更新条目时似乎存在问题，但在将某些内容添加到表中时似乎存在问题。

Answer 1

哦，我的。有这么多错误的事情。我们先解决你的问题。您的formbean实例化的IP值为192.168.178.21。您可以在JSP中使用此方法使用方法cjc.find_XML(Cardreader.class, readerIP);查找记录。你正在通过IP查找而不是ID。您更改ID并不重要。这就是为什么结果是一样的。

关于代码本身

• 切勿使用JSP代码内。 JSP是一个视图。如果可以的话，根本不要使用JSP。使用HTML和模板引擎（如Velocity）或Angular等框架，将数据绑定到HTML元素而不需要更多代码。

• 你的里程可能会有所不同，但我发现codegen（就像你为web服务客户端所做的那样）和大量的其他框架只会倾向于你想要做的事情。您正在调用一个调用服务器端REST客户端的JSP来查找数据库中的值;然后编译这个怪物并动态运行它，只是为了向客户端转发成功。

• 请看看AJAX请求以及Web框架如何实现它们。你会节省很多时间。