我想上传一个文件并将其保存到mysql数据库。到目前为止，我可以上传文件，打印其详细信息。但是，当我尝试通过帮助程序类将其存储在数据库中时，除ID之外的所有内容都将变为null。你能看一看，让我知道我错过了什么吗？另外，如果您发现任何我应该更改/修改为代码增强的内容，请与我们联系。
使用JSF / Primefaces上传文件：
<h:form enctype="multipart/form-data">
<p:growl id="messages" showDetail="true" />
<p:fileUpload value="#{fileUploadView1.file}" mode="simple"/>
<p:commandButton value="Submit" ajax="false" actionListener="#{fileUploadView1.upload}" />
</h:form>
FileBean：
@ManagedBean
@SessionScoped
public class FileUploadView1 {
private InputStream input;
private String fileName;
private Long fileSize;
private UploadedFile file;
@Inject
private FileController1 fileController;
public InputStream getInput() {
return input;
}
public String getFileName() {
return fileName;
}
public Long getFileSize() {
return fileSize;
}
public FileController1 getFileController() {
return fileController;
}
public UploadedFile getFile() {
return file;
}
public void setFile(UploadedFile file) {
this.file = file;
System.out.println("filesize " + file.getSize());
}
public void upload() throws IOException {
if (file != null) {
FacesMessage message = new FacesMessage("Succesful", file.getFileName() + " is uploaded.");
FacesContext.getCurrentInstance().addMessage(null, message);
input = file.getInputstream();
fileName = file.getFileName();
fileSize = file.getSize();
System.out.println("filesize3 " + file.getSize());
fileController.uploadFile(file);
}
}
}
FileController：
@ManagedBean
@SessionScoped
public class FileController1 {
private FileDbUtil1 fileDbUtil;
private Logger logger = Logger.getLogger(getClass().getName());
public FileController1() throws Exception {
fileDbUtil = FileDbUtil1.getInstance();
}
public String uploadFile(UploadedFile theFile) {
logger.info("Uploading File: " + theFile);
try {
fileDbUtil.uploadFile(theFile);
} catch (Exception exc) {
logger.log(Level.SEVERE, "Error adding files", exc);
addErrorMessage(exc);
return null;
}
return "welcomePrimefaces";
}
private void addErrorMessage(Exception exc) {
FacesMessage message = new FacesMessage("Error: " + exc.getMessage());
FacesContext.getCurrentInstance().addMessage(null, message);
}
}
FileDbUtil文件
public static FileDbUtil1 getInstance() throws Exception {
if (instance == null) {
instance = new FileDbUtil1();
}
return instance;
}
private FileDbUtil1() throws Exception {
dataSource = getDataSource();
}
private DataSource getDataSource() throws NamingException {
Context context = new InitialContext();
DataSource theDataSource = (DataSource) context.lookup(jndiName);
return theDataSource;
}
public void uploadFile(UploadedFile theFile) throws Exception {
fileName = theFile.getFileName();
input = theFile.getInputstream();
Connection myConn = null;
PreparedStatement myStmt = null;
try {
myConn = getConnection();
String sql = "insert into upload"
+ "(name, file)"
+ " values (?,?)";
myStmt = myConn.prepareStatement(sql);
// set params
myStmt.setString(1, fileName);
myStmt.setBinaryStream(2, input);
myStmt.executeUpdate();
} finally {
close(myConn, myStmt);
}
}
private Connection getConnection() throws Exception {
Connection theConn = dataSource.getConnection();
return theConn;
}
private void close(Connection theConn, Statement theStmt) {
close(theConn, theStmt, null);
}
private void close(Connection theConn, Statement theStmt, ResultSet theRs) {
try {
if (theRs != null) {
theRs.close();
}
if (theStmt != null) {
theStmt.close();
}
if (theConn != null) {
theConn.close();
}
} catch (Exception exc) {
exc.printStackTrace();
}
}
}
堆栈跟踪：请注意，我可以在调用帮助程序类之前打印文件大小
Info: filesize 3501
Info: filesize3 3501
Warning: java.lang.NullPointerException
javax.el.ELException: java.lang.NullPointerException
at com.sun.el.parser.AstValue.invoke(AstValue.java:293)
at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:304)
at javax.faces.event.MethodExpressionActionListener.processAction(MethodExpressionActionListener.java:149)
at javax.faces.event.ActionEvent.processListener(ActionEvent.java:88)
at javax.faces.component.UIComponentBase.broadcast(UIComponentBase.java:814)
at javax.faces.component.UICommand.broadcast(UICommand.java:300)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:790)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1282)
at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:198)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:658)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1682)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:318)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:416)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:283)
at com.sun.enterprise.v3.services.impl.ContainerMapper$HttpHandlerCallable.call(ContainerMapper.java:459)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:167)
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:235)
at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:283)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:200)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:132)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:111)
at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:536)
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$Worker.doWork(AbstractThreadPool.java:591)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:571)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException
at com.uploadfile.test.FileUploadView1.upload(FileUploadView1.java:70)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at com.sun.el.parser.AstValue.invoke(AstValue.java:289)
... 39 more
FATAL: JSF1073: javax.faces.FacesException caught during processing of INVOKE_APPLICATION 5 : UIComponent-ClientId=, Message=java.lang.NullPointerException
FATAL: java.lang.NullPointerException
javax.faces.FacesException: java.lang.NullPointerException
at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:89)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:198)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:658)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1682)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:318)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:416)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:283)
at com.sun.enterprise.v3.services.impl.ContainerMapper$HttpHandlerCallable.call(ContainerMapper.java:459)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:167)
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:235)
at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:283)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:200)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:132)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:111)
at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:536)
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$Worker.doWork(AbstractThreadPool.java:591)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:571)
at java.lang.Thread.run(Thread.java:745)
Caused by: javax.el.ELException: java.lang.NullPointerException
at com.sun.el.parser.AstValue.invoke(AstValue.java:293)
at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:304)
at javax.faces.event.MethodExpressionActionListener.processAction(MethodExpressionActionListener.java:149)
at javax.faces.event.ActionEvent.processListener(ActionEvent.java:88)
at javax.faces.component.UIComponentBase.broadcast(UIComponentBase.java:814)
at javax.faces.component.UICommand.broadcast(UICommand.java:300)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:790)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1282)
at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
... 31 more
Caused by: java.lang.NullPointerException
at com.uploadfile.test.FileUploadView1.upload(FileUploadView1.java:70)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at com.sun.el.parser.AstValue.invoke(AstValue.java:289)
... 39 more
答案 0 :(得分：1)
引起：java.lang.NullPointerException 在com.uploadfile.test.FileUploadView1.upload（FileUploadView1.java:68）
fileController没有被注入。
使用@Inject private FileController1 fileController。
BalusC对他的评论是正确的。