Java文件上传：Restful接口接收上传文件，缓存在本地

接口代码

import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;

import java.io.*;

@RestController
@RequestMapping(value = "/file")
@Slf4j
public class FileController {

    /**
     * windows下的文件路径
     */
    private final String File_PATH = "F:/upload/temp";

    @PostMapping(value = "/upload")
    String uploadFileBufferToLocal(MultipartFile file) {

            //将文件缓冲到本地
            boolean localFile = createLocalFile(File_PATH, file);
            if(!localFile){
                log.error("Create local file failed!");
                return "Create local file failed!";
            }
            log.info("Create local file successfully");

        return "Create local file successfully";
    }

    /**
     * 通过上传的文件名，缓冲到本地，后面才能解压、验证
     * @param filePath 临时缓冲到本地的目录
     * @param file
     */
    public boolean createLocalFile(String filePath,MultipartFile file) {
        File localFile = new File(filePath);
        //先创建目录
        localFile.mkdirs();

        String originalFilename = file.getOriginalFilename();
        String path = filePath+"/"+originalFilename;

        log.info("createLocalFile path = {}", path);

        localFile = new File(path);
        FileOutputStream fos = null;
        InputStream in = null;
        try {

            if(localFile.exists()){
                //如果文件存在删除文件
                boolean delete = localFile.delete();
                if (delete == false){
                    log.error("Delete exist file \"{}\" failed!!!",path,new Exception("Delete exist file \""+path+"\" failed!!!"));
                }
            }
            //创建文件
            if(!localFile.exists()){
                //如果文件不存在，则创建新的文件
                localFile.createNewFile();
                log.info("Create file successfully,the file is {}",path);
            }

            //创建文件成功后，写入内容到文件里
            fos = new FileOutputStream(localFile);
            in = file.getInputStream();
            byte[] bytes = new byte[1024];

            int len = -1;

            while((len = in.read(bytes)) != -1) {
                fos.write(bytes, 0, len);
            }

            fos.flush();
            log.info("Reading uploaded file and buffering to local successfully!");
        } catch (FileNotFoundException e) {
            e.printStackTrace();
            return false;
        } catch (IOException e) {
            e.printStackTrace();
            return false;
        }finally {
            try {
                if(fos != null) {
                    fos.close();
                }
                if(in != null) {
                    in.close();
                }
            } catch (IOException e) {
                log.error("InputStream or OutputStream close error : {}", e);
                return false;
            }
        }

        return true;
    }
}

过程是：

首先接口接收文件；

创建将要缓冲文件的目录，存在指定目录就不创建；

判断该目录是否有重复的文件名，如果有，先删除再生成，如果没有，就生成文件；

然后将通过文件流以每次1024bytes写入指定目录的文件；

最后关闭流。

更多Java文件操作可使用强大的Java文件工具：org.apache.commons.io.FileUtils;