Springboot use of poi export excel download

Because the practice of previous projects is to obtain property by reflection, so the demo is also a reflection, I see many online articles are stored in a List <Map> in, I do not know what these two which is more appropriate point, or have What better way to no.

First introduced pom, lombok optional 

<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>3.13</version>
</dependency>
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml</artifactId>
    <version>3.13</version>
</dependency>
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <optional>true</optional>
</dependency>

 

entity

@Data
@AllArgsConstructor
public class Student {
    public String name;
    public int score;
    public int age;
}

 

Service

import org.springframework.stereotype.Service;

import java.util.ArrayList;
import java.util.List;
@Service
public class StudentService {

    public List<Student> getList(Student student, int index, int size) {
        Student student1 = new Student("张三", 90, 18);
        Student student2 = new Student("李四", 85, 17);
        Student student3 = new Student("王五", 70, 19);
        List<Student> list = new ArrayList<>();
        list.add(student1);
        list.add(student2);
        list.add(student3);
        return list;
    }
}

 

Controller

import lombok.Cleanup;
import org.apache.poi.ss.usermodel.Workbook;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.util.List;

@RestController
public class StudentController {

    @Autowired
    StudentService studentService public;
        } catch (IOException e) {

    @RequestMapping ( "/ exportStudentExcel") 
    public ResponseEntity <byte []> exportExcel (Student Student) { 

        List <Student> List = studentService.getList (Student, 0, 10); // every time these lines only need to change 

        String fileName = "student achievement statistics"; // a time need to change a few lines 
        String [] getters = { "getName ", "getScore", "getAge"}; // each only need to change a few lines 
        String [] headers = { "name", "score", "age"}; // only need to change every few lines 

        Workbook wb = ExcelUtils.createWorkBook (list, getters , headers, student.getClass ()); // every time only a few lines need to change 

        @Cleanup ByteArrayOutputStream ByteArrayOutputStream new new OS = (); 
        the try { 
            wb.write (OS); 
            e.printStackTrace ();
        } 
        Byte [] os.toByteArray content = ();
        HttpHeaders httpHeaders = new HttpHeaders();
        try {
            fileName = URLEncoder.encode(fileName, "UTF-8");
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        httpHeaders.setContentDispositionFormData("attachment", fileName + ".xlsx");
        return new ResponseEntity<byte[]>(content, httpHeaders, HttpStatus.OK);
    }
}

 

ExcelUtils

ExcelUtils class {public 
    / ** 
     * create excel documents 
     * 
     * @param getters List of map of key array collection 
     * @param headers excel column name 
     * / 
    public static Workbook createWorkBook (List List, String [] getters, String [] headers , Class clazz) { 

        List <Method,> = getMethodsByStrs Methods (getters, clazz); 

        // Create .xlsx workbook 
        the workbook new new XSSFWorkbook WB = (); 
        // Create a first sheet (page), and designated 
        Sheet sheet = wb .createSheet ( "Sheet1"); 
        . // manually set the column width to be expressed as a first parameter set of columns, the second column indicates the width parameter, n is the number of columns of pixels to be high. 

        for (int I = 0 ; I <getters.length; I ++) { 
            sheet.setColumnWidth ((Short) I, (Short) (35.7 * 200 is)); 
        }

        // create a first row 
        Row = sheet.createRow header (0); 

        // create two cell formatting 
        the CellStyle cellStyle1 wb.createCellStyle = (); 
        the CellStyle cellStyle2 wb.createCellStyle = (); 

        // create two Font 
        Font font1 = wb.createFont (); // title Font 
        Font font2 = wb.createFont (); // text font 

        // title bold 
        font1.setBoldweight (Font.BOLDWEIGHT_BOLD); 

        // set two cell pattern 
        setCellStype (cellStyle1 , font1); 
        setCellStype (cellStyle2, font2); 

        // set header 
        for (int I = 0; I <headers.length; I ++) { 
            the Cell Cell header.createCell = (I); 
            cell.setCellValue (headers [I]) ; 
            cell.setCellStyle (cellStyle1);
        }

        //设置data
        int headersNum = 1;
        for (int i = 0; i < list.size(); i++) {
            Row row = sheet.createRow(i + headersNum);
            for (int j = 0; j < methods.size(); j++) {
                try {
                    Object invoke = methods.get(j).invoke(list.get(i));
                    if (invoke != null) {
                        row.createCell(j).setCellValue(invoke.toString());
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
        return wb;
    }

    private static void setCellStype(CellStyle cellStyle, Font font) {
        font.setFontHeightInPoints((short) 10);
        font.setColor(IndexedColors.BLACK.getIndex());
        cellStyle.setFont(font);
        cellStyle.setBorderLeft(CellStyle.BORDER_THIN);
        cellStyle.setBorderRight(CellStyle.BORDER_THIN);
        cellStyle.setBorderTop(CellStyle.BORDER_THIN);
        cellStyle.setBorderBottom(CellStyle.BORDER_THIN);
        cellStyle.setAlignment(CellStyle.ALIGN_CENTER);
    }

    private static List<Method> getMethodsByStrs(String[] getters, Class clazz) {
        List<Method> list = new ArrayList<>();
        for (String getter : getters) {
            try {
                list.add(clazz.getDeclaredMethod(getter));
            } catch (NoSuchMethodException e) {
                e.printStackTrace();
            }
        }
        return list;
    }
}