导出csv文件（浏览器直接下载）

落日映苍穹つ 2021-10-09 10:36 541阅读 0赞

1.添加工具类CSVUtil

import java.io.BufferedWriter;
    import java.io.File;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.OutputStreamWriter;
    import java.lang.reflect.Method;
    import java.util.HashMap;
    import java.util.Iterator;
    import java.util.List;
    
    import javax.servlet.http.HttpServletResponse;
    
    
    public class CSVUtil {
    	@SuppressWarnings({ "resource", "rawtypes", "unchecked" })
        public static void exportFile(HttpServletResponse response,
                HashMap map, List exportData, String fileds[])
                throws IOException {
            try {
                // 写入临时文件
                File tempFile = File.createTempFile("vehicle", ".csv");
                BufferedWriter csvFileOutputStream = null;
                // UTF-8使正确读取分隔符","
                csvFileOutputStream = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(tempFile), "GBK"), 1024);
                // 写入文件头部
                for (Iterator propertyIterator = map.entrySet().iterator(); propertyIterator.hasNext();) {
                    java.util.Map.Entry propertyEntry = (java.util.Map.Entry) propertyIterator.next();
                    csvFileOutputStream.write((String) propertyEntry.getValue() != null ? new String(((String) propertyEntry.getValue()).getBytes("GBK"), "GBK") : "");
                    if (propertyIterator.hasNext()) {
                        csvFileOutputStream.write(",");
                    }
                }
                csvFileOutputStream.write("\r\n");
                // 写入文件内容,
                // ============ //：Arraylist<实体类>填充实体类的基本信息==================
                for (int j = 0; exportData != null && !exportData.isEmpty()
                        && j < exportData.size(); j++) {
                    // RealTimeSO2 t = (BankWageMonth) exportData.get(j);
                    Class clazz = exportData.get(j).getClass();
                    String[] contents = new String[fileds.length];
                    for (int i = 0; fileds != null && i < fileds.length; i++) {
                        String filedName = toUpperCaseFirstOne(fileds[i]);
                        Object obj = null;
                        try {
                            Method method = clazz.getMethod(filedName);
                            method.setAccessible(true);
                            obj = method.invoke(exportData.get(j));
                        } catch (Exception e) {
    
                        }
                        String str = String.valueOf(obj);
                        if (str == null || str.equals("null"))
                            str = "";
                        contents[i] = str;
                    }
    
                    for (int n = 0; n < contents.length; n++) {
                        // 将生成的单元格添加到工作表中
                        csvFileOutputStream.write(contents[n]);
                        if(n < contents.length-1) { //去除掉最后一个,
                        	csvFileOutputStream.write(",");
                        }
                        
                    }
                    csvFileOutputStream.write("\r\n");
                }
    
                csvFileOutputStream.flush();
    
                /**
                 * 写入csv结束，写出流
                 */
                java.io.OutputStream out = response.getOutputStream();
                byte[] b = new byte[10240];
                java.io.File fileLoad = new java.io.File(tempFile.getCanonicalPath());
                response.reset();
                response.setContentType("application/csv");
    //            SimpleDateFormat fdate=new SimpleDateFormat("yyyy-MM-dd-HH-mm-ss");
    //            String trueCSVName=fdate.format(new Date())+".csv"; 
                String trueCSVName="导出数据.csv";
                response.setHeader("Content-Disposition", "attachment;  filename="+ new String(trueCSVName.getBytes("GBK"), "ISO8859-1")); 
                long fileLength = fileLoad.length();
                String length1 = String.valueOf(fileLength);
                response.setHeader("Content_Length", length1);
                java.io.FileInputStream in = new java.io.FileInputStream(fileLoad);
                int n;
                while ((n = in.read(b)) != -1) {
                    out.write(b, 0, n); // 每次写入out1024字节
                }
                in.close();
                out.close();
    
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    
        /**
         * 将第一个字母转换为大写字母并和get拼合成方法
         * 
         * @param origin
         * @return
         */
        private static String toUpperCaseFirstOne(String origin) {
            StringBuffer sb = new StringBuffer(origin);
            sb.setCharAt(0, Character.toUpperCase(sb.charAt(0)));
            sb.insert(0, "get");
            return sb.toString();
        }
    
     
    }

2.编写Controller进行调用

@RequestMapping(value = "/exportCsvs")
    					public Object exportCsvs(ParamsBean paramsBean,HttpServletResponse response) throws ParseException {
    
    					  List<CVSBean> list=	eventUserService.exportCsvs(paramsBean);
    				        HashMap map = new LinkedHashMap();
    				        map.put("1", "event_id");
    				        map.put("2", "type_name");
    				        map.put("3", "road_name");
    				        map.put("4", "date");
    				        map.put("5", "time");
    				        String fileds[] = new String[] { "event_id", "type_name","road_name","date","time" };
    				        try {
    							CSVUtil.exportFile(response, map, list, fileds);
    							/*
    							 * response：直接传入response
    							 * map：对应文件的第一行 
    							 * list：对应 List<CVSBean>  list对象形式
    							 * fileds：对应每一列的数据
    							 * */
    						} catch (IOException e) {
    							// TODO Auto-generated catch block
    							e.printStackTrace();
    						}//直接调用
    
    		            
    			        return null;
    			    }

3.省略 service和dao的方法

4.测试  浏览器输入访问地址级参数

文件下载成功：

![20190509174517436.png][]

[20190509174517436.png]: /images/20211009/02a9bd0ff0724ebd8d5b22f4e564cd39.png