JPQLの問い合わせでつまずいています＞＜

こんばんわ

現在JavaEEとJSFを使い、MySQLのテーブルから値を取り出す処理に苦戦しています

JPQLで問い合わせを行い、結果をList型にして返し、それをxhtmlで表示するプログラムです

実行手順
①mana_materialMana.xhtmlの45行目の<h:table>のなかのallメソッドを実行する

②Mana_materialMana.javaクラスのgetAll()を実行する

③EntityDb.javaのgetall()を実行する

ここで③のgetAll()を実行して,DBから問い合わせの結果をListに入れてxhtmlに表示したいのですが、
NullPointerExceptionが出て困っています＞＜

ちなみに、EntityDb.javaのJPQLの問い合わせは成功して、データも取り出せます

かなり初歩的なところでつまずいていると自覚しています
どうか皆様の力を貸してください＞＜

Mana_materialMana.xhtml

JavaEE　JSF
1
2       
3        <div class="table">
4            <h:dataTable value="#{mana_materialMana.all}" var="Item" border="1">
5                <h:column>
6                    <f:facet name="header">
7                             <h:outputText value="素材ID"/>
8                    </f:facet>
9                    <h:outputText value="#{Item.materialid}"/>  
10                </h:column>
11                <h:column>
12                    <f:facet name="header">
13                             <h:outputText value="素材名"/>
14                    </f:facet>
15                    <h:outputText value="#{Item.materialname}"/>
16                </h:column>
17            </h:dataTable>
18        </div>
19        
20          
21        <footer>
22            <h:button value="変更を保存" class="cbtn btn btncolor" />
23            <h:button value="削除" class="dbtn btn btncolor" />
24        </footer>
25
26        
27    </h:body>
28</html>

Mana_materialMana.java

JavaEE
1package bean;
2
3import entity.MaterialEntity;
4import java.util.LinkedHashMap;
5import java.util.List;
6import java.util.Map;
7import javax.enterprise.context.RequestScoped;
8import javax.inject.Named;
9import javax.persistence.Table;
10import util.EntityDb;
11
12@Named
13@RequestScoped
14
15public class Mana_materialMana {
16    
17    
18    private Integer city;       //選択結果
19    private String word;        //検索ワード
20   
21   
22     private String materialid ;
23     private String materialname ;
24
25     
26     EntityDb db;
27         
28     public List<MaterialEntity> getAll(){             //全素材データをリストに入れて返す
29          
30         return db.getAll();
31     }

EntityDb.java

Java
1* @author Owner
2 */
3@Stateless
4public class EntityDb{
5    @PersistenceContext
6    private EntityManager em;
7    
8    public void shopcreate(ShopEntity shopemployee){      //新しい店舗をデータベースに新規登録する
9        em.persist(shopemployee);
10    }
11    
12    public void materialcreate(MaterialEntity materialentity){      //新しい素材をデータベースに新規登録する
13        em.persist(materialentity);
14    }
15    
16    public List<MaterialEntity> getAll(){                             //DBに登録されている素材すべてを表示する
17            return em.createQuery("SELECT c FROM MaterialEntity c").getResultList();
18           
19    }
20    
21    
22}

MaterialEntity.java

JavaEE
1package entity;
2
3
4
5import java.io.Serializable;
6import java.util.List;
7import java.util.Objects;
8import javax.persistence.Entity;
9import javax.persistence.*;
10import javax.validation.constraints.NotNull;
11
12
13 
14
15 
16
17@Entity
18@Table(name = "material_table")
19public class MaterialEntity implements Serializable{
20        
21    public static final String Materialupdate = "Materialupdate";
22
23    @Id @NotNull    
24    private String materialid ;    //素材ID
25    @NotNull
26    private String materialname ;   //素材名
27    @OneToMany(mappedBy = "materialEntity")         //materialEntity⇔clothesEntityの双方向関係
28    private List<ClothesEntity> clothesentity;
29   
30    public MaterialEntity(){}
31    
32   
33    public MaterialEntity(String materialid,String materialname){
34        this.materialid = materialid;
35        this.materialname = materialname;
36    }
37
38    public String getMaterialid() {
39        return materialid;
40    }
41
42    public void setMaterialid(String materialid) {
43        this.materialid = materialid;
44    }
45
46    public String getMaterialname() {
47        return materialname;
48    }
49
50    public void setMaterialname(String materialname) {
51        this.materialname = materialname;
52    }
53    
54    
55   
56    
57}

java.lang.NullPointerException
	at bean.Mana_materialMana.getAll(Mana_materialMana.java:55)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at javax.el.BeanELResolver.getValue(BeanELResolver.java:363)
	at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:180)
	at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:208)
	at com.sun.el.parser.AstValue.getValue(AstValue.java:140)
	at com.sun.el.parser.AstValue.getValue(AstValue.java:204)
	at com.sun.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:226)
	at org.jboss.weld.module.web.el.WeldValueExpression.getValue(WeldValueExpression.java:50)
	at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:97)
	at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:194)
	at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:181)
	at javax.faces.component.UIData.getValue(UIData.java:760)
	at javax.faces.component.UIData.getDataModel(UIData.java:1873)
	at javax.faces.component.UIData.setRowIndexWithoutRowStatePreserved(UIData.java:503)
	at javax.faces.component.UIData.setRowIndex(UIData.java:492)
	at com.sun.faces.renderkit.html_basic.TableRenderer.encodeBegin(TableRenderer.java:81)
	at javax.faces.component.UIComponentBase.encodeBegin(UIComponentBase.java:564)
	at javax.faces.component.UIData.encodeBegin(UIData.java:1177)
	at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1667)
	at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1673)
	at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1673)
	at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:492)
	at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:194)
	at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:156)
	at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:126)
	at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:100)
	at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:223)
	at javax.faces.webapp.FacesServlet.executeLifecyle(FacesServlet.java:732)
	at javax.faces.webapp.FacesServlet.service(FacesServlet.java:475)
	at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1622)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:258)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160)
	at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:654)
	at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:593)
	at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:159)
	at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:371)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:238)
	at com.sun.enterprise.v3.services.impl.ContainerMapper$HttpHandlerCallable.call(ContainerMapper.java:516)
	at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:213)
	at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:206)
	at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:180)
	at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:242)
	at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
	at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:284)
	at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:201)
	at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:133)
	at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:112)
	at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
	at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:539)
	at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:112)
	at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:117)
	at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:56)
	at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:137)
	at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:593)
	at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:573)
	at java.lang.Thread.run(Thread.java:745)

行動規範の内容に同意します

回答1件

ベストアンサー

ソース拝見いたしました。

Mana_materialMana.javaのEntityDb db宣言では、CDIなどしていないので（インスタンスが空なので）null pointer errorが出ているのではないでしょうか。EntityDb宣言の前に@EJBアノテーションか@Injectアノテーションなど必要なのではないでしょうか。

最近JavaEEから離れているので深く説明できず済みません。

投稿2018/12/28 14:53

編集2018/12/28 14:54