Well, I have implemented a distinct query in hibernate. It returns me result. But, while casting the fields are getting interchanged. So, it generates casting error. What should be the solution?
As an example, I do have database, “ProjectAssignment” that has three fields, aid, pid & userName. I want all distinct userName data from this table. I have applied query :
select distinct userName, aid, pid from ProjectAssignment
Whereas the ProjectAssignment.java file has the fields in sequence aid, pid & userName. Now, here the userName is first field in output. So, Casting is not getting possible.
Also, query :
select aid, pid, distinct userName from ProjectAssignment
is not working.
What is the proper query for the same ? Or what else the solution ?
The code is as below :
System Utilization Service Bean Method where I have to retrieve data :
public List<ProjectAssignment> getProjectAssignments() {
projectAssignments = ProjectAssignmentHelper.getAllResources(); //Here comes the error
return projectAssignments;
}
ProjectAssignmentHelper from where I fetch Data :
package com.hibernate;
import java.util.List;
import org.hibernate.Query;
import org.hibernate.Session;
public class ProjectAssignmentHelper {
public static List<ProjectAssignment> getAllResources() {
List<ProjectAssignment> projectMasters;
Session session = HibernateUtil.getSessionFactory().openSession();
Query query = session.createQuery("select distinct aid, pid, userName from ProjectAssignment");
projectMasters = (List<ProjectAssignment>) query.list();
session.close();
return projectMasters;
}
}
Hibernate Data Bean :
package com.hibernate;
public class ProjectAssignment implements java.io.Serializable {
private short aid;
private String pid;
private String userName;
public ProjectAssignment() {
}
public ProjectAssignment(short aid) {
this.aid = aid;
}
public ProjectAssignment(short aid, String pid, String userName) {
this.aid = aid;
this.pid = pid;
this.userName = userName;
}
public short getAid() {
return this.aid;
}
public void setAid(short aid) {
this.aid = aid;
}
public String getPid() {
return this.pid;
}
public void setPid(String pid) {
this.pid = pid;
}
public String getUserName() {
return this.userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
}
Error :
For input string: “userName”
java.lang.NumberFormatException: For input string: "userName" at java.lang.NumberFormatException.forInputString(NumberFormatException.java:48) at java.lang.Integer.parseInt(Integer.java:447) at java.lang.Integer.parseInt(Integer.java:497) at javax.el.ArrayELResolver.toInteger(ArrayELResolver.java:375) at javax.el.ArrayELResolver.getValue(ArrayELResolver.java:195) at javax.el.CompositeELResolver.getValue(CompositeELResolver.java:175) at com.sun.faces.el.FacesCompositeELResolver.getValue(FacesCompositeELResolver.java:72) at com.sun.el.parser.AstValue.getValue(AstValue.java:116) at com.sun.el.parser.AstValue.getValue(AstValue.java:163) at com.sun.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:219) at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:102) at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:190) at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:178) at javax.faces.component.UICommand.getValue(UICommand.java:218) at org.primefaces.component.commandlink.CommandLinkRenderer.encodeMarkup(CommandLinkRenderer.java:113) at org.primefaces.component.commandlink.CommandLinkRenderer.encodeEnd(CommandLinkRenderer.java:54) at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:878) at org.primefaces.renderkit.CoreRenderer.renderChild(CoreRenderer.java:70) at org.primefaces.renderkit.CoreRenderer.renderChildren(CoreRenderer.java:54) at org.primefaces.component.datatable.DataTableRenderer.encodeTable(DataTableRenderer.java:525) at org.primefaces.component.datatable.DataTableRenderer.encodeMarkup(DataTableRenderer.java:407) at org.primefaces.component.datatable.DataTableRenderer.encodeEnd(DataTableRenderer.java:193) at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:878) at org.primefaces.renderkit.CoreRenderer.renderChild(CoreRenderer.java:70) at org.primefaces.renderkit.CoreRenderer.renderChildren(CoreRenderer.java:54) at org.primefaces.component.tabview.TabViewRenderer.encodeContents(TabViewRenderer.java:198) at org.primefaces.component.tabview.TabViewRenderer.encodeMarkup(TabViewRenderer.java:130) at org.primefaces.component.tabview.TabViewRenderer.encodeEnd(TabViewRenderer.java:48) at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:878) at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1620) at javax.faces.render.Renderer.encodeChildren(Renderer.java:168) at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:848) at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1613) at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1616) at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1616) at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:380) at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:126) at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:127) at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101) at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139) at javax.faces.webapp.FacesServlet.service(FacesServlet.java:313) at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1523) at org.apache.catalina.core.ApplicationDispatcher.doInvoke(ApplicationDispatcher.java:802) at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:664) at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:497) at org.apache.catalina.core.ApplicationDispatcher.doDispatch(ApplicationDispatcher.java:468) at org.apache.catalina.core.ApplicationDispatcher.dispatch(ApplicationDispatcher.java:364) at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:314) at org.apache.jasper.runtime.PageContextImpl.forward(PageContextImpl.java:783) at org.apache.jsp.welcome_jsp._jspService(welcome_jsp.java from :59) at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:109) at javax.servlet.http.HttpServlet.service(HttpServlet.java:847) at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:406) at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:483) at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:373) at javax.servlet.http.HttpServlet.service(HttpServlet.java:847) at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1523) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:279) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:188) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:641) at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:97) at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:85) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:185) at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:332) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:233) at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:165) at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:791) at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:693) at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:954) at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:170) at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:135) at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:102) at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:88) at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:76) at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:53) at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:57) at com.sun.grizzly.ContextTask.run(ContextTask.java:69) at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:330) at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:309) at java.lang.Thread.run(Thread.java:619)
Why do you want to use HQL?
The idea of Hibernate is to work with entities and not with tables. Ideally, you would load the entities and iterate through them getting the fields you want.
I would suggest you to use Hibernate Criteria and Criterion to that query.
And then iterate through the list getting the fields you want.