springboot poi derived using data generating excel (.xlsx) files

Introduction: in the actual development often need to export data from the database into excel file, poi one embodiment is more commonly derived framework. Simple to read excel file in the previous one has explained

The project implementation requirements: user issues a request to export student information, download excel file containing all student information to the machine. Just put the key code , not put up is very simple, self-brain supplement

Overall process (the server): receiving a request ------> ------ extracted database data> data is saved as a temporary file excel ------> allows the browser in response to the first temporary file download ------> delete temporary files

Project structure:

1. Import dependence

<!--poi-->
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>4.1.0</version>
</dependency>
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml</artifactId>
    <version>4.1.0</version>
</dependency>

2.controller

package com.zjk.excel.controller;

import com.zjk.excel.service.UserServiceI;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import javax.servlet.http.HttpServletResponse;
import java.io.*;

/**
 * @Auther: zjk
 * @Date: 2019/9/16
 * @Description:
 */
@Controller
@RequestMapping("/user")
public class UserController {
    @Autowired
    UserServiceI UserServiceI; 

    @ RequestMapping ( "/ Export" )
     public  void exportStu (HttpServletResponse the Response) {
         // set the default download filename 
        String name = "Student Information table .xlsx" ;
         the try {
             // avoid Chinese file name garbled, the UTF8 recombined break ISO-8859-1 encoding 
            name = new new String (name.getBytes ( "the UTF8"), "ISO-8859-1" ); 
        } the catch (UnsupportedEncodingException E) { 
            e.printStackTrace (); 
        } 
        // type response header set 
        the response.setContentType ( "file application / vnd.openxmlformats-officedocument.spreadsheetml.sheet" );
        // let the browser download the file, name is above the default file name to download 
        response.addHeader ( "Content-Disposition", "attachment; filename = \ "" + name + "\" " ); 
        InputStream inputStream = null ; 
        OutputStream outputStream = null ;
         // has become excel data is stored in a temporary file service layer, and return to the path of the temporary file 
        String DownloadPath = userServiceI.exportStu ();
         // create file objects based on the path for temporary files, you need to use FileInputStream read 
        file file = new new file (DownloadPath);
        try {
            // by FileInputStream read the temporary file, ServletOutputStream written to the temporary file browser 
            inputStream = new new  FileInputStream (file);
            the outputStream = response.getOutputStream ();
             int len = -1 ;
             byte [] B = new new  byte [1024 ];
             the while ((len = inputStream .read (B)) = -1! ) { 
                OutputStream.write (B); 
            } 
            // refresh 
            outputStream.flush (); 
         } the catch (Exception E) { 
            e.printStackTrace (); 
        } the finally {
            // Close the input and output streams 
            the try {
                 IF (inputStream =! Null {) 
                    inputStream.close (); 
                } 
            } the catch (IOException E) { 
                e.printStackTrace (); 
            } 
            the try {
                 IF (! The outputStream = null ) { 
                    outputStream.close (); 
                } 
            } the catch (IOException E) { 
                e.printStackTrace (); 
            } 

        } 
        // Finally to delete the temporary file if the use of a temporary file stream, File.delete () is not deleted
         File.delete (); 
    } 
}

3.service

package com.zjk.excel.service.impl;

import com.zjk.excel.dao.StudentDao;
import com.zjk.excel.dao.UserDao;
import com.zjk.excel.entity.Student;
import com.zjk.excel.service.UserServiceI;
import org.apache.poi.xssf.usermodel.XSSFCell;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.io.*;
importjava.util.List;
 Import java.util.UUID; 

/ ** 
 * @Auther: ZJK 
 * @date: 2019/9/16 
 * @Description: 
 * / 
@Service 
public  class UserService the implements UserServiceI {
　　// create a temporary file storage path
     Private String TEMP = "D: \\ TEMP \\ \\ Excel" ; 

    @Autowired 
    UserDao userDao; 

    @Autowired 
    StudentDAO StudentDAO; 

    @Override 
    public String exportStu () { 

        List <Student> List = studentDao.queryAllStu ();
         / / create workbooks  
        xSSFWorkbook xssfWorkbook =new new XSSFWorkbook ();
        // Create a worksheet 
        XSSFSheet Sheet = xssfWorkbook.createSheet (); 
        xssfWorkbook.setSheetName ( 0, "Student Information Form" );
         // Create a header 
        XSSFRow head = sheet.createRow (0 ); 
        String [] Heads = { "No. "," name "," age "," sex "," phone number " };
         for ( int I = 0; I <. 5; I ++ ) { 
            XSSFCell Cell = head.createCell (I); 
            cell.setCellValue (Heads [ I]); 
        } 
        for ( int I =. 1; I <=. 4; I ++ ) {
            Student student  = List.get (I -. 1 );
             // create a row, starting from the second row, so that the for loop i from 1 starts taking 
            XSSFRow Row = sheet.createRow (i);
             // create a cell and padding data 
            XSSFCell cell = row.createCell (0 ); 
            cell.setCellValue (student.getS_id ()); 
            Cell = row.createCell (. 1 ); 
            cell.setCellValue (student.getS_name ()); 
            Cell = row.createCell (2 ); 
            cell.setCellValue (student.getS_age ()); 
            the Cell = row.createCell (3 ); 
            cell.setCellValue ( "male" .equals (student.getS_gender () trim ( )) " man":? "female" );
            the Cell = row.createCell (4 a FileOutputStream (DownloadPath); );
            cell.setCellValue (student.getS_tel ()); 
        } 
        // create temporary files directory 
        File File = new new File (the TEMP);
         IF (! {File.Exists ()) 
            file.mkdirs (); 
        } 
        // temporary file path / file name 
        String file + DownloadPath = "\\" + System.currentTimeMillis () + UUID.randomUUID (); 
        the OutputStream the outputStream = null ;
         the try { 
　　　　　　　data in memory will be written to the local FileOutputStream // use, generates a temporary file 
            the outputStream = new new 
            xssfWorkbook.write (the outputStream); 
            outputStream.flush ();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if(outputStream != null) {
                    outputStream.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return downloadPath;
    }
}

4. Effects

After the WPS Open: can be said to be very ugly, then optimize it

Increases in service in the following code: Overall still very troublesome, create CellStyle, but also you want to change the style of the cell were cell.setCellStyle (style1) can

* Bo master version is relatively new, so there are many places older version differences

        //创建styleHead
        CellStyle styleHead = xssfWorkbook.createCellStyle();
        styleHead.setFillForegroundColor(IndexedColors.SKY_BLUE.getIndex());//背景色
        styleHead.setFillPattern(FillPatternType.SOLID_FOREGROUND);
        styleHead.setAlignment(HorizontalAlignment.CENTER);//水平居中
        XSSFFont font = xssfWorkbook.createFont();
        font.setBold(true);//加粗
        font.setFontHeight((short)240);//字体大小
        styleHead.setFont(font);
        //创建style1
        CellStyle style1 = xssfWorkbook.createCellStyle();
        style1.setFillForegroundColor(IndexedColors.LEMON_CHIFFON.getIndex());//背景色
        style1.setFillPattern(FillPatternType.SOLID_FOREGROUND);
        style1.setAlignment(HorizontalAlignment.CENTER);//水平居中
        //创建style2
        CellStyle style2 = xssfWorkbook.createCellStyle();
        style2.setFillForegroundColor(IndexedColors.LIGHT_TURQUOISE.getIndex());//背景色
        style2.setFillPattern(FillPatternType.SOLID_FOREGROUND);
        style2.setAlignment(HorizontalAlignment.CENTER);//水平居中　　　　
　　　　 sheet.setColumnWidth(4,3500);//给第5列设置宽度(tel栏)

优化后：

总结一下：

poi的简单使用还是不难的，说白了就数据库一个表对应一个sheet，表的一行对应一个row，表某一行的一个数据对应一个cell，嗯，就是这么简单。

　　说到调样式就非常头疼了，而且新版本的较之前改动比较大，百度出来的东西很多都没法用，勉强捣鼓了一些出来。

　　最后给自己打打气-——世上无难事，只要肯登攀！