如何将记录合并在一起 [英] How to merge records together
本文介绍了如何将记录合并在一起的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我能够更新数据库，因此用户保存的每一部分都可以在数据库的正确列中正常工作，但是我现在想要实现的是，而不是保存到新行中，请检查那里studentNumber，并且如果它已经在表中包含记录(必须走远)，则将列更新为该记录，而不是开始一个新记录
i am able to update the database so for each section a user saves it saves there work fine, in the correct column of the database, but what i am now trying to achieve is instead of saving into a new row, check there studentNumber and if it already has a record in the table (which it will have to to get this far ) update the columns to that record rather than starting a new one
我该怎么做?
当前，这是我的代码:
这是u.i.他们在其中选择值，然后按提交
this is the u.i. where they select the value and press submit
<p:spinner id="ajaxspinner80-100" value="#{editMarkingBean.markSectionTwo.markSectionTwo}"
stepFactor="1" min="80" max="100" disabled="#{formBean.number != 8}">
<p:ajax update="ajaxspinnervalue" process="@this" />
</p:spinner>
保存按钮
<p:commandButton action="#{editMarkingBean.markSectionTwo}" value="#{bundle.buttonSave}" update=":growl" icon="ui-icon-disk"/>
支持bean是:
@Named(value = "editMarkingBean")
@ViewScoped
public class EditMarkingController {
private String searchString;
private String ordering;
private String criteria;
private String match;
private Date today;
private String caseMatch;
private int spinnerField;
private Marking markSectionOne;
private Marking studentNumber;
private Marking markSectionTwo;
private MarkingService markingService;
private Marking markToEdit;
@Inject
private MarkingFacade markingFacade;
@PostConstruct
public void init() {
//this.markToEdit = this.markingFacade.find(studentNumber);
this.markSectionTwo = new Marking();
}
public String markSectionTwo() {
this.markingFacade.edit(markSectionTwo);
this.setMessage("Mark Saved");
markSectionTwo = new Marking();
this.setMessage("Mark Saved");
// now navigating to the next page
return "/lecturer/marking/marking-section-three";
}
private void setMessage(String message) {
FacesContext fc = FacesContext.getCurrentInstance();
fc.addMessage(null, new FacesMessage(message, ""));
}
public Marking getMarkSectionTwo() {
return markSectionTwo;
}
public void setMarkSectionTwo(Marking markSectionTwo) {
this.markSectionTwo = markSectionTwo;
}
public String getSearchString() {
return searchString;
}
public void setSearchString(String searchString) {
this.searchString = searchString;
}
public String getOrdering() {
return ordering;
}
public void setOrdering(String ordering) {
this.ordering = ordering;
}
public String getCriteria() {
return criteria;
}
public void setCriteria(String criteria) {
this.criteria = criteria;
}
public String getMatch() {
return match;
}
public void setMatch(String match) {
this.match = match;
}
public Date getToday() {
return today;
}
public void setToday(Date today) {
this.today = today;
}
public String getCaseMatch() {
return caseMatch;
}
public void setCaseMatch(String caseMatch) {
this.caseMatch = caseMatch;
}
public int getSpinnerField() {
return spinnerField;
}
public void setSpinnerField(int spinnerField) {
this.spinnerField = spinnerField;
}
public Marking getMarkSectionOne() {
return markSectionOne;
}
public void setMarkSectionOne(Marking markSectionOne) {
this.markSectionOne = markSectionOne;
}
public Marking getStudentNumber() {
return studentNumber;
}
public void setStudentNumber(Marking studentNumber) {
this.studentNumber = studentNumber;
}
public MarkingService getMarkingService() {
return markingService;
}
public void setMarkingService(MarkingService markingService) {
this.markingService = markingService;
}
public MarkingFacade getMarkingFacade() {
return markingFacade;
}
public void setMarkingFacade(MarkingFacade markingFacade) {
this.markingFacade = markingFacade;
}
}
但当前仅将具有数据的新行添加到数据库中，而不是尝试将其与数据库中已包含的具有特定学生编号的学生合并在一起的数据
but currently only adds a new row with the data to the database rather than trying to merge it with the data already contained in the database for a student with a certain student number
我怎样才能做到这一点?谢谢大家的帮助:)
how can i achieve this ? thanks guys for your help :)
我尝试过:
private Marking markToEdit;
@Inject
private MarkingFacade markingFacade;
@PostConstruct
public void init() {
this.markToEdit = this.markingFacade.find(studentNumber);
//this.markSectionTwo = new Marking();
}
public String markSectionTwo() {
this.markingFacade.edit(markSectionTwo);
this.setMessage("Mark Saved");
// markSectionTwo = new Marking();
//this.setMessage("Mark Saved");
// now navigating to the next page
return "/lecturer/marking/marking-section-three";
}
但出现错误:
exception
javax.servlet.ServletException: WELD-000049 Unable to invoke public void sws.control.EditMarkingController.init() on sws.control.EditMarkingController@4109691f
root cause
org.jboss.weld.exceptions.WeldException: WELD-000049 Unable to invoke public void sws.control.EditMarkingController.init() on sws.control.EditMarkingController@4109691f
root cause
java.lang.reflect.InvocationTargetException
root cause
javax.ejb.EJBException
root cause
java.lang.IllegalArgumentException: An instance of a null PK has been incorrectly provided for this find operation.
推荐答案
我使用与您非常相似的方法，但是名称不同.我将其张贴在这里，所以我想您可以有个好主意.
I use a quite similar approach as yours, but with different names. I'll post it here, so I think you can have some idea.
我的方法是在合并之前明确检查实体.
My way is to check the entity explicitly before merging it.
我的JSF CRUD看起来像这样
My JSF CRUD looks like this
xhtml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:p="http://primefaces.org/ui">
<h:head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>DataSource Manager</title>
</h:head>
<h:body>
<h:form id="ds">
<p:spacer height="10" />
<p:fieldset legend="Insert/Edit Data Source">
<p:panel id="insertUpdateForm">
<h:panelGrid columns="2">
<p:outputLabel for="name" value="Data Source Name:" style="width:100px;"/>
<p:inputText id="name" value="#{dataSourceMB.dataSource.name}"/>
<p:outputLabel for="user" value="User:" style="width:100px;"/>
<p:inputText id="user" value="#{dataSourceMB.dataSource.user}"/>
<p:outputLabel for="driver" value="Driver:" style="width:100px;"/>
<p:inputText id="driver" value="#{dataSourceMB.dataSource.driver}" />
</h:panelGrid>
</p:panel>
<p:panel>
<p:commandButton value="Save" action="#{dataSourceMB.saveDataSource}" update="dsList,insertUpdateForm" />
<p:commandButton value="Clear" action="#{dataSourceMB.clearDataSource}" update="insertUpdateForm" />
<p:commandButton value="Test Connection" action="#{dataSourceMB.testConnection}"/>
</p:panel>
</p:fieldset>
<p:spacer height="10" />
<p:fieldset legend="Data Sources">
<p:panel>
<p:dataTable
var="ds"
value="#{dataSourceMB.listDataSources}"
paginator="true" rows="10"
paginatorTemplate="{RowsPerPageDropdown} {FirstPageLink} {PreviousPageLink} {CurrentPageReport} {NextPageLink} {LastPageLink}"
rowsPerPageTemplate="10,50,100"
id="dsList">
<p:column headerText="ID">
<h:outputText value="#{ds.id}" />
</p:column>
<p:column headerText="Name">
<h:outputText value="#{ds.name}" />
</p:column>
<p:column headerText="JDBC">
<h:outputText value="#{ds.jdbc} " />
</p:column>
<!-- check http://jqueryui.com/themeroller/ for icons -->
<p:column headerText="" style="width:2%">
<p:commandButton icon="ui-icon-pencil" action="#{dataSourceMB.editDataSource}" title="Edit" update=":ds:insertUpdateForm">
<f:setPropertyActionListener value="#{ds}" target="#{dataSourceMB.selectedDataSource}" />
</p:commandButton>
</p:column>
<p:column headerText="" style="width:2%">
<p:commandButton icon="ui-icon-trash" action="#{dataSourceMB.removeDataSource}" title="Remove" update=":ds:insertUpdateForm,dsList">
<f:setPropertyActionListener value="#{ds}" target="#{dataSourceMB.selectedDataSource}" />
</p:commandButton>
</p:column>
</p:dataTable>
</p:panel>
</p:fieldset>
</h:form>
</h:body>
</html>
我的托管bean
import java.io.Serializable;
import java.util.List;
import javax.annotation.PostConstruct;
import javax.ejb.EJB;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.ViewScoped;
import org.apache.log4j.Logger;
import DataSourceEJB;
import JSFUtilEJB;
import DataSource;
@ManagedBean
@ViewScoped
public class DataSourceMB implements Serializable {
private static final long serialVersionUID = 871363306742707990L;
private static Logger log = Logger.getLogger(DataSourceMB.class);
@EJB
private JSFUtilEJB jsfUtilEJB;
@EJB
private DataSourceEJB dataSourceEJB;
private DataSource dataSource;
private DataSource selectedDataSource;
private List<DataSource> listDataSources;
@PostConstruct
public void init() {
try {
this.dataSource = new DataSource();
this.listDataSources = this.dataSourceEJB.listDataSources();
} catch (Exception e) {
jsfUtilEJB.addErrorMessage(e,"Could not list");
}
}
public void removeDataSource(){
try {
this.dataSourceEJB.removeDataSource(this.selectedDataSource);
jsfUtilEJB.addInfoMessage("Removed "+this.selectedDataSource.getName());
if (this.dataSource != null && this.dataSource.getId() != null && this.dataSource.getId().equals(this.selectedDataSource.getId())){
this.dataSource = null;
}
this.listDataSources = this.dataSourceEJB.listDataSources();
} catch (Exception e) {
jsfUtilEJB.addErrorMessage(e,"Could not remove");
}
}
public void saveDataSource(){
try {
this.dataSourceEJB.saveDataSource(this.dataSource);
jsfUtilEJB.addInfoMessage("Saved "+this.dataSource.getName());
this.dataSource = new DataSource();
this.listDataSources = this.dataSourceEJB.listDataSources();
} catch (Exception e) {
jsfUtilEJB.addErrorMessage(e,"Could not save");
}
}
public void editDataSource(){
this.dataSource = this.selectedDataSource;
}
public void clearDataSource(){
this.dataSource = new DataSource();
}
public DataSource getDataSource() {
return dataSource;
}
public void setDataSource(DataSource dataSource) {
this.dataSource = dataSource;
}
public DataSource getSelectedDataSource() {
return selectedDataSource;
}
public void setSelectedDataSource(DataSource selectedDataSource) {
this.selectedDataSource = selectedDataSource;
}
public List<DataSource> getListDataSources() {
return listDataSources;
}
public void setListDataSources(List<DataSource> listDataSources) {
this.listDataSources = listDataSources;
}
}
我的EJB
import java.io.IOException;
import java.sql.SQLException;
import java.util.List;
import javax.ejb.Stateless;
import javax.inject.Inject;
import DataSource;
@Stateless
public class DataSourceEJB {
@Inject
private BaseService baseService;
public List<DataSource> listDataSources() {
return this.baseService.getDataSourceDAO().getAll();
}
public void removeDataSource(DataSource ds) throws Exception {
DataSource a = this.baseService.getDataSourceDAO().find(ds.getId());
this.baseService.getDataSourceDAO().delete(a);
}
public void saveDataSource(DataSource ds) throws Exception {
DataSource a = this.baseService.getDataSourceDAO().find(ds.getId());
if (a == null){
this.baseService.getDataSourceDAO().add(ds);
}else{
this.baseService.getDataSourceDAO().edit(ds);
}
}
public DataSource getById(long id) {
return this.baseService.getDataSourceDAO().find(id);
}
public DataSource getByName(String name) {
return this.baseService.getDataSourceDAO().findByName(name);
}
}
DAO
public E find(Long id) {
return (E)entityManager.find(clazz, id);
}
public void add(E entity) throws Exception {
entityManager.persist(entity);
}
public E edit(E entity) throws Exception {
return entityManager.merge(entity);
}
public void delete(E entity) throws Exception {
entityManager.remove(entity);
}
这篇关于如何将记录合并在一起的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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