JAVA实现下载resources下的文件

JAVA实现下载resources下的文件 概述

 JAVA实现resources下的文件，本次实现的是下载一个模板文件。导入的包都是默认的io流这些。

首先在pom.xml引入包

             org.apache.maven.plugins
                maven-resources-plugin
                2.6
                
                    
                        xlsx
                        xls
                        docx
                    
                

 ExcelUtil工具类

import com.alibaba.nacos.common.utils.CollectionUtils;
import org.apache.poi.hssf.usermodel.HSSFCell;

import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;

import javax.servlet.http.HttpServletResponse;
import java.io.ByteArrayOutputStream;
import java.util.List;

public class ExcelUtil {

    private static Workbook appendTitles(Workbook wb, List titles) throws Exception {

        Sheet sheet = wb.getSheetAt(0);
        // 设置表头的说明
        Row topRow = sheet.getRow(1);
        for (int i = 0; i < titles.size(); i++) {
            Cell cell = topRow.createCell(i + 6);
//            cell.setCellType(HSSFCell.CELL_TYPE_NUMERIC);
            cell.setCellValue(titles.get(i));
            sheet.setColumnWidth( i + 6, titles.get(i).getBytes().length * 258);
        }
        return wb;
    }

    
    public static void export(Workbook wb, String fileName, List titles,
                              HttpServletResponse response) throws Exception {
        try {
            if(!CollectionUtils.isEmpty(titles)){
                wb = appendTitles(wb, titles);
            }
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            wb.write(baos);
            baos.flush();
            byte[] aa = baos.toByteArray();
            response.addHeader("Content-Disposition",
                    "attachment;filename*=utf-8'zh_cn'" + fileName);
            response.setHeader("Content-Type", "application/vnd.ms-excel");
            response.setCharacterEncoding("UTF-8");
            response.getOutputStream().write(aa);
            response.setContentLength(aa.length);
        } catch (Exception e) {
            e.printStackTrace();
            throw new Exception("write excel to stream error!", e);
        } finally {
            if (response.getOutputStream() != null) {
                response.getOutputStream().flush();
            }
        }
    }
}

ProjectConfiguration（扫描resources下面的文件）

import org.apache.commons.io.IOUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;
import org.springframework.stereotype.Component;
import javax.annotation.PostConstruct;
import java.io.IOException;
import java.io.InputStream;

@Component
public class ProjectConfiguration {

    @Autowired
    private ResourceLoader resourceLoader;
    public static byte[] fileBytes;
    public static String fileName;

    @PostConstruct
    public void init(){
        Resource resource = resourceLoader.getResource("classpath:templates/areaTemplate.xls");
        try {
            InputStream inputStream = resource.getInputStream();
            fileName = "areaTemplate.xls";
            fileBytes = IOUtils.toByteArray(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Controlleer控制层调用

 
    @CrossOrigin
    @PostMapping(value = "/downloadTemplate" , produces = {"application/json;charset=UTF-8"})
    public WeaResult downloadTemplate(HttpServletResponse response){
    byte[] fileSource = ProjectConfiguration.fileBytes;
    //防止对原数据进行 *** 作
    byte[] fileBytes = Arrays.copyOf(fileSource, fileSource.length);
    //下载模板
    try {
      Workbook wb = WorkbookFactory.create(new ByteArrayInputStream(fileBytes));
      List titleList = new ArrayList();
      ExcelUtil.export(wb, ProjectConfiguration.fileName, titleList, response);
    } catch (Exception e) {
      
      e.printStackTrace();
    }
  }

测试（使用postman测试）

 

 

 可以看见就实现下载了resources下面的文件了。