不兼容类型-找到void java.util.optional

Question

有一个红色下划线，下划线为消息:不兼容类型。必需：...在jpafindbyid方法上找到了model.constants:java.util.optional。

Constants constants=constantsRepository.findById(1L);

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "pkid")
private Long id;

public Long getId() {
    return id;
}

public void setId(Long id) {
    this.id = id;
}

package com.destek.salaryCalculation.repository;

import com.destek.salaryCalculation.model.Constants;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface ConstantsRepository extends  JpaRepository<Constants, Long>{

}

package com.destek.salaryCalculation.controller;

import com.destek.salaryCalculation.helper.BesCreateExcelHelper;
import com.destek.salaryCalculation.model.Personal;
import com.destek.salaryCalculation.repository.PersonalRepository;
import org.apache.poi.openxml4j.exceptions.InvalidFormatException;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.List;

@RestController
@CrossOrigin(origins = "http://localhost:3000")
@RequestMapping("/salarycalc")
public class BesCreateController {

    @Autowired
    private PersonalRepository personalRepository;

    @GetMapping("/besexcel/{group}")
    public void exportToExcelByGroup(HttpServletResponse response,@PathVariable String group) throws IOException, InvalidFormatException {
        response.setContentType("application/octet-stream");

        String headerKey = "Content-Disposition";
        String headerValue = "attachment; filename=bes.xlsx";
        response.setHeader(headerKey, headerValue);
        List<Personal> listPersonal = personalRepository.getListPersonelByGroup(group);
        System.out.println(listPersonal);
        BesCreateExcelHelper excelExporter = new 
       BesCreateExcelHelper(listPersonal);
       excelExporter.export(response);
    }
}

和BesCreateHelper java

package com.destek.salaryCalculation.helper;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.Calendar;
import java.util.List;
import java.util.Optional;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import com.destek.salaryCalculation.model.Constants;
import com.destek.salaryCalculation.model.Personal;
import com.destek.salaryCalculation.repository.ConstantsRepository;
import org.apache.poi.openxml4j.exceptions.InvalidFormatException;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.XSSFFont;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.springframework.beans.factory.annotation.Autowired;

public class BesCreateExcelHelper {
    private XSSFWorkbook workbook;
    private XSSFSheet sheet;
    private List<Personal> listPersonalBes;

    @Autowired
    private ConstantsRepository constantsRepository;
    public BesCreateExcelHelper(List<Personal> listPersonalBes) throws IOException, InvalidFormatException {
        FileInputStream inputStream = new FileInputStream(new File("bes.xlsx"));
        this.listPersonalBes = listPersonalBes;
        //workbook = new XSSFWorkbook();
        workbook = (XSSFWorkbook) WorkbookFactory.create(inputStream);
        sheet = workbook.getSheetAt(0);
        inputStream.close();
    }

    private void createCell(Row row, int columnCount, Object value, CellStyle style) {
        //sheet.autoSizeColumn(columnCount);
        Cell cell = row.createCell(columnCount);
        if (value instanceof Integer) {
            cell.setCellValue((Integer) value);
        } else if (value instanceof Boolean) {
            cell.setCellValue((Boolean) value);
        }else {
            cell.setCellValue((String) value);
        }
        cell.setCellStyle(style);
    }

    private void writeDataLines() {
        int rowCount = sheet.getLastRowNum();

        CellStyle style = workbook.createCellStyle();
        XSSFFont font = workbook.createFont();
        font.setFontHeight(15);
        style.setFont(font);

       Optional<Constants> constants2 = constantsRepository.findById(1L);
       Constants constants = constants2.orElseThrow(() ->new RuntimeException("No such data found"));;

        for (Personal personal : listPersonalBes) {
            Row row = sheet.createRow(++rowCount);
            int columnCount = 0;
            int i = 1;
            createCell(row, columnCount++, i++, style);
            createCell(row, columnCount++, personal.getName(), style);
            createCell(row, columnCount++, personal.getIdentity().toString(), style);
            double besAmount=0;
            if(personal.getBes()==1){
                int numberDayOfMonth=constants.getDayOfWork();
           int sanitaryPermit=personal.getSanitaryPermit();
            double grossWages=0;
           if(sanitaryPermit<numberDayOfMonth) {
                grossWages = constants.getDailyWage() * (numberDayOfMonth - sanitaryPermit);
           }
               float socialHelp=constants.getSocialHelp();
               float mealBonus=constants.getMealBonus();
               float tisSupport=constants.getTisSupport();
               double deservedVehicleHelp=0;
               if(numberDayOfMonth>0){
                   int dayOfWork=numberDayOfMonth-sanitaryPermit-personal.getAnnualPermit();
                   // TODO: 11.01.2021 busTicketHelp tekrar hesaplatılacak.
                   double busTicketHelp=3.25*numberDayOfMonth;
                    deservedVehicleHelp=busTicketHelp*dayOfWork/numberDayOfMonth;
               }
               double mealPrice=(constants.getDayOfWork()-(personal.getSanitaryPermit()- Math.floor(personal.getSanitaryPermit()/7)*2)-personal.getAnnualPermit())*constants.getMealBonus();
               double extraWorkHourPrice=Math.ceil(personal.getExtraWorkHour()*constants.getDailyWage()/5);
               double extraWorkHourPriceSpecial=Math.ceil(personal.getExtraWorkHourSpecial()*constants.getDailyWage()/7.5*1.5);
               double mealException=constants.getMinimumWage()/30*6/100*mealPrice;
               double sgkPrimBaseAmount=grossWages+socialHelp+mealBonus+tisSupport+deservedVehicleHelp+mealPrice+extraWorkHourPrice+extraWorkHourPriceSpecial+mealException;
               besAmount=sgkPrimBaseAmount*0.03;
               }
            createCell(row, columnCount++, String.valueOf(besAmount), style);
        }
    }
    public void export(HttpServletResponse response) throws IOException {
        //writeHeaderLine();
        writeDataLines();
        ServletOutputStream outputStream = response.getOutputStream();
        workbook.write(outputStream);
        // workbook.close();
        outputStream.close();
    }
}

Answer 1

正如@anishb所述，您需要从可选的解析值，但我不会使用

... = constants.get(); 

因为这是危险的constants.get()将抛出NosuchelementException如果值不存在

您应该使用：

Constants value = constants.orElse(null); 

Constants value = constants.orElseThrow(() -> new CustomException()); 

BesCreateExcelHelper将类似于：

@Component
public class BesCreateExcelHelper {
...
public void init(List<Personal> listPersonalBes) { // notice this was the constructor logic
  .......
}
}

然后将BesCreateExcelHelper注入到BesCreateController中，并将..new BesCreateController()行替换为BesCreateExcelHelper.init(listPersonal)

#2您可以保持besCreateExcelHelper原样，但删除常量提取行并从外部传递常量值，当然，这里的外部意味着其他一些Spring组件，就像您在ExportToExcelByGroup中所做的那样，因此您只需在控制器中执行ConstantsRepository.findById(1L)；然后将其作为第二个构造函数参数传递给Helper类

...

constant = ...constantsRepository.findById(1L);
excelExporter = new 
       BesCreateExcelHelper(listPersonal, constant);

我更喜欢第一选择