[alibaba/easyexcel]填充Excel 遇到OOM

你好，我把实现流程完整描述一下。

背景： 我们项目要实现一个 模板下载，模板里面有个sheet（不是第一个sheet）的数据是动态查询填充上去的。模板文件存储在OSS， OSS 会返回路径，例如：http://yunexpress-fileupload.oss-cn-shenzhen.aliyuncs.com/wos/workOrder/issueFile1。 该 OSS 路径可以下载附件。

问题： 附件大小在 100-200KB 左右，每下载一次，JVM 内存飙升上百MB，次数多了，造成OOM

技术： springBoot

控制层：FileController

PostMapping(value = "/download") public void downloadFile(HttpServletResponse response, String ossUrl) throws Exception { fileService.downloadFile(response, param); }

服务实现层：FileServiceImpl

public void downloadFile(HttpServletResponse response, String ossUrl) throws IOException { URL url = new URL(ossUrl); URLConnection conn = url.openConnection(); conn.setConnectTimeout(3 * 1000); // 设置超时间为3秒 conn.setRequestProperty("User-Agent","Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/57.0.2987.110 Safari/537.36"); InputStream inputStream = conn.getInputStream();

String fileName = "数据填充模板.xlsx";
//数据填充
issueDynamicFill(response, fileName, inputStream);

}

public void issueDynamicFill(HttpServletResponse response,
InputStream inputStream) throws IOException { ServletOutputStream outputStream = exportHeader(response, fileName);

ExcelWriter excelWriter = EasyExcel.write(outputStream).withTemplate(inputStream).build();
WriteSheet writeSheet = EasyExcel.writerSheet().sheetNo(2).build();

//dynamicFillAddValues 原本是查库的，为省略时间，数据写死
excelWriter.fill(dynamicFillAddValues(), writeSheet);

excelWriter.finish();
inputStream.close();
outputStream.flush();

}

public ServletOutputStream exportHeader(HttpServletResponse response, String fileName) throws IOException { response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"); response.setHeader("Access-Control-Expose-Headers", "Content-Disposition"); response.setHeader("Content-Disposition", "attachment; filename=" + URLEncoder.encode(fileName, CHARACTER)); return response.getOutputStream(); }

public List dynamicFillAddValues(){ return initData(); }

//初始化数据 public List initData(){ String jsonStr = "[\n" + " {\n" + " \"addValueCode\":\"201\",\n" + " \"addValueName\":\"换单\"\n" + " },\n" + " {\n" + " \"addValueCode\":\"203\",\n" + " \"addValueName\":\"更换包装\"\n" + " },\n" + " {\n" + " \"addValueCode\":\"206\",\n" + " \"addValueName\":\"加固\"\n" + " },\n" + " {\n" + " \"addValueCode\":\"207\",\n" + " \"addValueName\":\"核重\"\n" + " },\n" + " {\n" + " \"addValueCode\":\"205\",\n" + " \"addValueName\":\"分箱\"\n" + " },\n" + " {\n" + " \"addValueCode\":\"204\",\n" + " \"addValueName\":\"合箱\"\n" + " },\n" + " {\n" + " \"addValueCode\":\"202\",\n" + " \"addValueName\":\"清点拍照\"\n" + " },\n" + " {\n" + " \"addValueCode\":\"208\",\n" + " \"addValueName\":\"核重拍照\"\n" + " },\n" + " {\n" + " \"addValueCode\":\"209\",\n" + " \"addValueName\":\"核材积\"\n" + " },\n" + " {\n" + " \"addValueCode\":\"210\",\n" + " \"addValueName\":\"核材积拍照\"\n" + " }\n" + "]"; return JSONObject.parseArray(jsonStr, AddValueService.class);
}

实体：

@Data @Builder @AllArgsConstructor @NoArgsConstructor @ApiModel(value = "AddValueService") public class AddValueService {

@ApiModelProperty(value = "编号")
private String addValueCode;

@ApiModelProperty(value = "名称")
private String addValueName;    

}