我有一个我想要自动装配的存储库的DaoImpl。这个班级是这样的
@Repository("referralDao")
@Transactional(value = "txManager", propagation = Propagation.REQUIRES_NEW , readOnly = true)
public class ReferralDaoImpl extends ReferralCommonDao implements IReferralDao {
@Override
public ReferralProperty getReferralProperty(String name) {
String sQuery = " FROM " + ReferralProperty.class.getSimpleName() + " WHERE name = :name";
Query query = getCurrentSession().createQuery(sQuery);
query.setParameter("name", name);
ReferralProperty property = (ReferralProperty)query.uniqueResult();
return property;
}
}
我还有一个控制器，我正在自动装配这个类。控制器：
@Controller
@RequestMapping(value="UploadExcel")
public class ExcelController {
private boolean isMultipart;
private String filePath;
private String fileName;
private int maxFileSize = 50 * 1024;
private int maxMemSize = 4 * 1024;
private File file ;
@Autowired
private ReferralDaoImpl referralDaoImpl;
private ReferralProperty referralProperty;
@RequestMapping(value="/excel", method=RequestMethod.GET )
public String excel() {
return "UploadExcel/excel";
}
@RequestMapping(value="UploadNew" , method=RequestMethod.POST)
public String excel1() {
return "UploadExcel/excel";
}
@RequestMapping(value = "Upload", method = RequestMethod.POST)
public String doPost (HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException , Exception{
isMultipart = ServletFileUpload.isMultipartContent(request);
response.setContentType("text/html");
referralProperty = referralDaoImpl.getReferralProperty("excel.sheet.directory");
filePath = referralProperty.getValue();
// java.io.PrintWriter out = response.getWriter( );
if( !isMultipart ){
return "index";
}
DiskFileItemFactory factory = new DiskFileItemFactory();
factory.setSizeThreshold(maxMemSize);
factory.setRepository(new File("/home/aman"));
ServletFileUpload upload = new ServletFileUpload(factory);
upload.setSizeMax( maxFileSize );
try{
List fileItems = upload.parseRequest(request);
Iterator i = fileItems.iterator();
while ( i.hasNext () )
{
FileItem fi = (FileItem)i.next();
if ( !fi.isFormField () )
{
String name = fi.getName();
System.out.println(name + "\n\n\n\n\n\n\n");
referralProperty = referralDaoImpl.getReferralProperty("excel.sheet.name");
/*referralProperty.setValue(name);
referralProperty.setDescription(name);
referralProperty = referralDaoImpl.getReferralProperty("excel.sheet.name");
System.out.println(referralProperty.getDescription() + "\n\n\n\n\n\n\n");*/
fileName = referralProperty.getValue();
if( fileName.lastIndexOf("\\") >= 0 ){
file = new File( filePath +
fileName.substring( fileName.lastIndexOf("\\"))) ;
}else{
file = new File( filePath +
fileName.substring(fileName.lastIndexOf("\\")+1)) ;
}
fi.write( file );
processExcel p = new processExcel();
int p1 = p.Excel();
// Excel();
}
}
}catch(Exception ex) {
System.out.println(ex);
}
return "UploadExcel/downloadexcel";
}
@RequestMapping(value = "Download", method = RequestMethod.POST)
public void doPost1(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
PrintWriter out = response.getWriter();
referralProperty = referralDaoImpl.getReferralProperty("excel.sheet.directory");
String filepath = referralProperty.getValue();
referralProperty = referralDaoImpl.getReferralProperty("excel.sheet.name");
String filename = referralProperty.getValue();
response.setContentType("APPLICATION/OCTET-STREAM");
response.setHeader("Content-Disposition", "attachment; filename=\"" + filename + "\"");
FileInputStream fileInputStream = new FileInputStream(filepath + filename);
int i;
while ((i = fileInputStream.read()) != -1) {
out.write(i);
}
fileInputStream.close();
out.close();
}
public int Excel() throws Exception
{
System.out.println(referralDaoImpl.toString());
System.out.println(referralProperty.toString());
try {
boolean eligible;
referralProperty = referralDaoImpl.getReferralProperty("excel.sheet.directory");
String filepath = referralProperty.getValue();
referralProperty = referralDaoImpl.getReferralProperty("excel.sheet.name");
String filename = referralProperty.getValue();
FileInputStream myInput = new FileInputStream(filepath+filename);
XSSFWorkbook myWorkBook = new XSSFWorkbook(myInput);
XSSFSheet mySheet = myWorkBook.getSheetAt(0);
XSSFRow row = mySheet.getRow(0);
int emailColumn = 0;
int eligibilityColumn = row.getLastCellNum();
for(Cell cell : row) {
XSSFCell cell1 = (XSSFCell)cell;
if(cell1.getStringCellValue().equals("email") || cell1.getStringCellValue().equals("Email"))
{
emailColumn = cell1.getColumnIndex();
break;
}
}
XSSFCell cell2 = (XSSFCell)row.createCell(eligibilityColumn);
cell2.setCellValue("Eligibility");
for (Row row1 : mySheet)
{
XSSFCell cell1 = (XSSFCell)row1.getCell(emailColumn);
if(row1.getRowNum()!=0 && cell1!=null) {
eligible = isValidRefree(cell1.getStringCellValue());
if(eligible==true)
{
cell2 = (XSSFCell)row1.createCell(eligibilityColumn);
cell2.setCellValue("Eligible");
}
else
{
cell2 = (XSSFCell)row1.createCell(eligibilityColumn);
cell2.setCellValue("InEligible");
}
}
}
myInput.close();
FileOutputStream output_file =new FileOutputStream(new File(filepath+filename));
System.out.println(filepath+filename);
myWorkBook.write(output_file);
output_file.close();
} catch (Exception e) {
System.out.println(e.toString());
}
return 1;
}
public boolean isValidRefree( String email)
{
return true;
}
}
这里的课程自动装配没有任何问题，一切正常。现在，如果我创建另一个包和一个名为processExcel.java的类，该类看起来像这样：
@Service
public class processExcel {
@Autowired
private ReferralDaoImpl referralDaoImpl;
private ReferralProperty referralProperty;
public int Excel() throws Exception
{
//System.out.println(referralDaoImpl.toString());
System.out.println(referralProperty.toString());
try {
boolean eligible;
System.out.println("akjsfbjaksf" + "\n\n\n\n\n");
referralProperty = referralDaoImpl.getReferralProperty("excel.sheet.directory");
System.out.println("akjsfbjaksf" + "\n\n\n\n\n");
String filepath = referralProperty.getValue();
System.out.println("akjsfbjaksf" + "\n\n\n\n\n");
referralProperty = referralDaoImpl.getReferralProperty("excel.sheet.name");
String filename = referralProperty.getValue();
System.out.println("akjsfbjaksf" + "\n\n\n\n\n");
FileInputStream myInput = new FileInputStream(filepath+filename);
XSSFWorkbook myWorkBook = new XSSFWorkbook(myInput);
XSSFSheet mySheet = myWorkBook.getSheetAt(0);
Iterator<Row> rowIter = mySheet.rowIterator();
while(rowIter.hasNext()){
System.out.println("akjsfbjaksf" + "\n\n\n\n\n");
XSSFRow myRow = (XSSFRow) rowIter.next();
Iterator<Cell> cellIter = myRow.cellIterator();
if(cellIter.hasNext()) {
XSSFCell cell = (XSSFCell)cellIter.next();
String email = cell.getStringCellValue();
eligible = isValidRefree (email);
if(eligible == true)
{
if (cellIter.hasNext()){
XSSFCell cell1 = (XSSFCell) cellIter.next();
cell1.setCellValue("Eligible");
}
else
{
XSSFCell cell1 = myRow.createCell(1);
cell1.setCellValue("Eligible");
}
}
else
{
if(cellIter.hasNext()){
XSSFCell cell1 = (XSSFCell) cellIter.next();
cell1.setCellValue("InEligible");
}
else
{
XSSFCell cell1 = myRow.getCell(1);
cell1.setCellValue("InEligible");
}
}
}
}
myInput.close();
FileOutputStream output_file =new FileOutputStream(new File(filepath+"ama.xlsx"));
System.out.println(filepath+filename);
myWorkBook.write(output_file);
output_file.close();
} catch (Exception e) {
System.out.println(e.toString());
}
return 1;
}
public boolean isValidRefree( String email)
{
return true;
}
}
并尝试自动装配ReferralDaoImpl它不起作用并显示NUllPointerException。为什么会这样？
答案 0 :(得分：1)
检查您的代码我看到您在processExcel ExcelController手动实例化processExcel p = new processExcel();，这是您的问题。
为了让Spring能够自动装配你需要使用Spring创建的bean，当你使用new这样做时，Spring对这个对象一无所知。
使用它的正确方法是自动装配该类，并使用此bean而不是创建自己的bean：
@Autowired
private processExcel processExcel;
快速抬头，不要使用小写的类名称，并始终自动装配接口，而不是实现。
答案 1 :(得分：-1)
确保在加载此类之前初始化并加载spring上下文。