上傳文件異步處理注意事項

時間 2021-02-13

標籤 java web spring apache tomcat dom 異步 async code 欄目 Java 简体版

原文原文鏈接

問題

上傳Excel進行處理不用用戶等待處理完以後會郵件告知處理結果
因此是異步處理java

public void readExcel(@RequestParam("file") MultipartFile file) {
        
    CompletableFuture.runAsync(() -> {
        try {
            service.readExcel(file);
        } catch (IOException e) {
            e.printStackTrace();
        }
    });
}

實際使用的過程當中發現常常上傳失敗報錯以下web

java.io.FileNotFoundException: /private/tmp/upload_2cc08ec8_c3eb_4633_8c0f_0cc20e34ff55_00000000.tmp (No such file or directory)
    at java.io.FileInputStream.open0(Native Method)
    at java.io.FileInputStream.open(FileInputStream.java:195)
    at java.io.FileInputStream.<init>(FileInputStream.java:138)
    at org.apache.tomcat.util.http.fileupload.disk.DiskFileItem.getInputStream(DiskFileItem.java:188)
    at org.apache.catalina.core.ApplicationPart.getInputStream(ApplicationPart.java:100)
    at org.springframework.web.multipart.support.StandardMultipartHttpServletRequest$StandardMultipartFile.getInputStream(StandardMultipartHttpServletRequest.java:297)

緣由

請求返回後會自動刪除臨時文件致使實際讀取Excel的時候找不到文件spring

// org.apache.catalina.core.ApplicationPart#delete
public void delete() throws IOException {
    fileItem.delete();
}

解決

複製該臨時文件將複製後的文件傳給異步程序處理處理完以後刪除該臨時文件apache

String uuid = UUID.randomUUID().toString().replace('-', '_');
String tmpFileName = String.format("/tmp/upload_%s.tmp", uuid);
final File tmpFile = new File(tmpFileName);
try {
    Files.copy(file.getInputStream(), tmpFile.toPath());
} catch (IOException e) {
    e.printStackTrace();
}
CompletableFuture.runAsync(() -> {
    try {
        service.readExcel(tmpFile);
    } catch (IOException e) {
        e.printStackTrace();
    }
});