File和MultipartFile互相转化工具类

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1 File转MultipartFile工具类

引入以下依赖：

<dependency>
    <groupId>commons-fileupload</groupId>
    <artifactId>commons-fileupload</artifactId>
    <version>1.3.1</version>
</dependency>

下面是具体代码：

package com.oldlu.file.excel.one;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileItemFactory;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.multipart.commons.CommonsMultipartFile;

public class FileUtil {

    public MultipartFile fileToMultipartFile(File file) {
        FileItem fileItem = createFileItem(file);
        MultipartFile multipartFile = new CommonsMultipartFile(fileItem);
        return multipartFile;
    }

    private static FileItem createFileItem(File file) {
        FileItemFactory factory = new DiskFileItemFactory(16, null);
        FileItem item = factory.createItem("textField", "text/plain", true, file.getName());
        int bytesRead = 0;
        byte[] buffer = new byte[8192];
        try {
            FileInputStream fis = new FileInputStream(file);
            OutputStream os = item.getOutputStream();
            while ((bytesRead = fis.read(buffer, 0, 8192)) != -1) {
                os.write(buffer, 0, bytesRead);
            }
            os.close();
            fis.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return item;
    }

}

复制代码
　　注意：导入的是org.apache.commons下的包，一定记住，我踩过的雷。。。

2 MultipartFile转File

接受前端文件：

MultipartFile file111 = ((MultipartHttpServletRequest) httpServletRequest).getFile("前端传得文件名");

转换：

package com.oldlu.common.FileUtil;/**
 * Created by oldlu
 */
 
import org.springframework.web.multipart.MultipartFile;
 
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
 
/**
 * @ClassName MultipartFileToFile
 * @Description MultipartFile转fie
 * @Author oldlu
 **/
public class MultipartFileToFile {
 
    /**
     * MultipartFile 转 File
     *
     * @param file
     * @throws Exception
     */
    public static File multipartFileToFile(MultipartFile file) throws Exception {
 
        File toFile = null;
        if (file.equals("") || file.getSize() <= 0) {
            file = null;
        } else {
            InputStream ins = null;
            ins = file.getInputStream();
            toFile = new File(file.getOriginalFilename());
            inputStreamToFile(ins, toFile);
            ins.close();
        }
        return toFile;
    }
 
    //获取流文件
    private static void inputStreamToFile(InputStream ins, File file) {
        try {
            OutputStream os = new FileOutputStream(file);
            int bytesRead = 0;
            byte[] buffer = new byte[8192];
            while ((bytesRead = ins.read(buffer, 0, 8192)) != -1) {
                os.write(buffer, 0, bytesRead);
            }
            os.close();
            ins.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
 
    /**
     * 删除本地临时文件
     * @param file
     */
    public static void delteTempFile(File file) {
    if (file != null) {
        File del = new File(file.toURI());
        del.delete();
    }
}
}