feat: 导出

nladmin-system/nlsso-server/src/main/java/org/nl/common/utils/FileUtil.java

@@ -19,12 +19,18 @@ import cn.hutool.core.io.IoUtil;
 import cn.hutool.core.util.IdUtil;
 import cn.hutool.poi.excel.BigExcelWriter;
 import cn.hutool.poi.excel.ExcelUtil;
+import com.google.common.collect.Lists;
+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.util.IOUtils;
 import org.apache.poi.xssf.streaming.SXSSFSheet;
+import org.apache.poi.xssf.streaming.SXSSFWorkbook;
 import org.nl.common.exception.BadRequestException;
 import org.nl.config.language.LangProcess;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import org.springframework.util.CollectionUtils;
 import org.springframework.web.multipart.MultipartFile;
 
 import javax.servlet.ServletOutputStream;
@@ -34,9 +40,7 @@ import java.io.*;
 import java.security.MessageDigest;
 import java.text.DecimalFormat;
 import java.text.SimpleDateFormat;
-import java.util.Date;
-import java.util.List;
-import java.util.Map;
+import java.util.*;
 
 /**
  * File工具类，扩展 hutool 工具包
@@ -45,6 +49,7 @@ import java.util.Map;
  * @date 2018-12-27
  */
 public class FileUtil extends cn.hutool.core.io.FileUtil {
+    private static final Integer BATCH_WRITE_EXCEL_ROW_AMOUNT = 500;
 
     private static final Logger log = LoggerFactory.getLogger(FileUtil.class);
 
@@ -227,6 +232,86 @@ public class FileUtil extends cn.hutool.core.io.FileUtil {
         IoUtil.close(out);
     }
 
+    /**
+     * 流导出
+     * @param list
+     * @param response
+     * @throws IOException
+     */
+    public void downloadExcelIO(List<Map<String, String>> list, String[] columnExcelNameArr, HttpServletResponse response) {
+        List<Map<String, String>> lastRestDataList = list;
+        int blockNum = 0;
+        List<String> allFileLocations = new ArrayList<>();
+        ServletOutputStream out = null;
+        try {
+            boolean allFinish = false;
+            while (!allFinish) {
+                int thisFileRowNumber = 1;
+                SXSSFWorkbook wb = null;
+                try {
+                    // 流式写入EXCEL，只保留少数行(比如50行)数据在内存，防止内存溢出
+                    wb = new SXSSFWorkbook(BATCH_WRITE_EXCEL_ROW_AMOUNT);
+                    Sheet sh = wb.createSheet();
+                    Row titleRow = sh.createRow(0);
+                    for (int cellNum = 0; cellNum < columnExcelNameArr.length; cellNum++) {
+                        Cell cell = titleRow.createCell(cellNum);
+                        cell.setCellValue(columnExcelNameArr[cellNum]);
+                    }
+                    if (!CollectionUtils.isEmpty(lastRestDataList)) {
+                        for (int i = 0; i < lastRestDataList.size(); i++) {
+                            Row dataRow = sh.createRow(thisFileRowNumber);
+                            Map<String, String> columnMap = lastRestDataList.get(i);
+                            for (int cellNum = 0; cellNum < columnExcelNameArr.length; cellNum++) {
+                                Cell cell = dataRow.createCell(cellNum);
+                                String valueStr = columnMap.get(columnExcelNameArr[cellNum]);
+                                cell.setCellValue(valueStr);
+                            }
+                            thisFileRowNumber++;
+                        }
+                    }
+
+                    String localFilePath = SYS_TEM_DIR + IdUtil.fastSimpleUUID() + blockNum + ".xlsx";
+                    allFileLocations.add(localFilePath);
+                    response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet;charset=utf-8");
+                    response.setHeader("Content-Disposition", "attachment;filename=" + localFilePath);
+                    out = response.getOutputStream();
+                    wb.write(out);
+                    // 必须清理流式写入Excel生成的临时文件
+                    wb.dispose();
+                    allFinish = true;
+                } catch (Exception ex) {
+                    log.warn(ex.getMessage());
+                    throw new BadRequestException(ex.getMessage());
+                } finally {
+                    if (out != null) {
+                        try {
+                            out.flush();
+                            out.close();
+                        } catch (IOException e) {
+                            log.warn(e.getMessage());
+                        }
+                    }
+                    if (wb != null) {
+                        try {
+                            wb.dispose();
+                        } catch (Exception e) {
+                            log.warn(e.getMessage());
+                        }
+                    }
+                }
+            }
+        } finally {
+            if (out != null) {
+                try {
+                    out.flush();
+                    out.close();
+                } catch (IOException e) {
+                    log.warn(e.getMessage());
+                }
+            }
+        }
+    }
+
     public static String getFileType(String type) {
         String documents = "txt doc pdf ppt pps xlsx xls docx";
         String music = "mp3 wav wma mpa ram ra aac aif m4a";
@@ -343,5 +428,4 @@ public class FileUtil extends cn.hutool.core.io.FileUtil {
     public static String getMd5(File file) {
         return getMd5(getByte(file));
     }
-
 }