JAX-RS之上传文件

今天学习的是jax-rs中的上传文件.
1 首先要包含的是resteasy-multipart-provider.jar这个文件

2) 之后是简单的HTML FORM
  

JAX-RS Upload Form

  
Select a file :
  


  

3 代码如下,先列出,再讲解:
  

 import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
import java.util.Map;
import javax.ws.rs.Consumes;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.core.Response;
import org.apache.commons.io.IOUtils;
import org.jboss.resteasy.plugins.providers.multipart.InputPart;
import org.jboss.resteasy.plugins.providers.multipart.MultipartFormDataInput;

@Path("/file")
public class UploadFileService {

    private final String UPLOADED_FILE_PATH = "d:\\";

    @POST
    @Path("/upload")
    @Consumes("multipart/form-data")
    public Response uploadFile(MultipartFormDataInput input) {

        String fileName = "";

        Map> uploadForm = input.getFormDataMap();
        List inputParts = uploadForm.get("uploadedFile");

        for (InputPart inputPart : inputParts) {

         try {

            MultivaluedMap header = inputPart.getHeaders();
            fileName = getFileName(header);

            //convert the uploaded file to inputstream
            InputStream inputStream = inputPart.getBody(InputStream.class,null);

            byte [] bytes = IOUtils.toByteArray(inputStream);

            //constructs upload file path
            fileName = UPLOADED_FILE_PATH + fileName;

            writeFile(bytes,fileName);

            System.out.println("Done");

          } catch (IOException e) {
            e.printStackTrace();
          }

        }

        return Response.status(200)
            .entity("uploadFile is called, Uploaded file name : " + fileName).build();

    }

    /**
     * header sample
     * {
     *  Content-Type=[image/png],
     *  Content-Disposition=[form-data; name="file"; filename="filename.extension"]
     * }
     **/
    //get uploaded filename, is there a easy way in RESTEasy?
    private String getFileName(MultivaluedMap header) {

        String[] contentDisposition = header.getFirst("Content-Disposition").split(";");

        for (String filename : contentDisposition) {
            if ((filename.trim().startsWith("filename"))) {

                String[] name = filename.split("=");

                String finalFileName = name[1].trim().replaceAll("\"", "");
                return finalFileName;
            }
        }
        return "unknown";
    }

    //save to somewhere
    private void writeFile(byte[] content, String filename) throws IOException {

        File file = new File(filename);

        if (!file.exists()) {
            file.createNewFile();
        }

        FileOutputStream fop = new FileOutputStream(file);

        fop.write(content);
        fop.flush();
        fop.close();

    }
}

 import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
import java.util.Map;
import javax.ws.rs.Consumes;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.core.Response;
import org.apache.commons.io.IOUtils;
import org.jboss.resteasy.plugins.providers.multipart.InputPart;
import org.jboss.resteasy.plugins.providers.multipart.MultipartFormDataInput;
 
@Path("/file")
public class UploadFileService {
 
	private final String UPLOADED_FILE_PATH = "d:\\";
 
	@POST
	@Path("/upload")
	@Consumes("multipart/form-data")
	public Response uploadFile(MultipartFormDataInput input) {
 
		String fileName = "";
 
		Map> uploadForm = input.getFormDataMap();
		List inputParts = uploadForm.get("uploadedFile");
 
		for (InputPart inputPart : inputParts) {
 
		 try {
 
			MultivaluedMap header = inputPart.getHeaders();
			fileName = getFileName(header);
 
			//convert the uploaded file to inputstream
			InputStream inputStream = inputPart.getBody(InputStream.class,null);
 
			byte [] bytes = IOUtils.toByteArray(inputStream);
 
			//constructs upload file path
			fileName = UPLOADED_FILE_PATH + fileName;
 
			writeFile(bytes,fileName);
 
			System.out.println("Done");
 
		  } catch (IOException e) {
			e.printStackTrace();
		  }
 
		}
 
		return Response.status(200)
		    .entity("uploadFile is called, Uploaded file name : " + fileName).build();
 
	}
 
	/**
	 * header sample
	 * {
	 * 	Content-Type=[image/png], 
	 * 	Content-Disposition=[form-data; name="file"; filename="filename.extension"]
	 * }
	 **/
	//get uploaded filename, is there a easy way in RESTEasy?
	private String getFileName(MultivaluedMap header) {
 
		String[] contentDisposition = header.getFirst("Content-Disposition").split(";");
 
		for (String filename : contentDisposition) {
			if ((filename.trim().startsWith("filename"))) {
 
				String[] name = filename.split("=");
 
				String finalFileName = name[1].trim().replaceAll("\"", "");
				return finalFileName;
			}
		}
		return "unknown";
	}
 
	//save to somewhere
	private void writeFile(byte[] content, String filename) throws IOException {
 
		File file = new File(filename);
 
		if (!file.exists()) {
			file.createNewFile();
		}
 
		FileOutputStream fop = new FileOutputStream(file);
 
		fop.write(content);
		fop.flush();
		fop.close();
 
	}
}

   这里,用户选择了文件上传后,会URL根据REST的特性,自动map
到uploadFile方法中,然后通过:
   Map> uploadForm = input.getFormDataMap();

List inputParts = uploadForm.get("uploadedFile"); 
   找出所有的上传文件框(可以是多个),然后进行循环工作:
  首先是获得每个文件头的HEADER,用这个
MultivaluedMap header = inputPart.getHeaders();
然后在header中取出文件名,这里使用的方法是getFileName,另外写了个方法:

 

  private String getFileName(MultivaluedMap header) {

    String[] contentDisposition = header.getFirst("Content-Disposition").split(";");

    for (String filename : contentDisposition) {
        if ((filename.trim().startsWith("filename"))) {

            String[] name = filename.split("=");

            String finalFileName = name[1].trim().replaceAll("\"", "");
            return finalFileName;
        }
    }
    return "unknown";
}

   private String getFileName(MultivaluedMap header) {
 
		String[] contentDisposition = header.getFirst("Content-Disposition").split(";");
 
		for (String filename : contentDisposition) {
			if ((filename.trim().startsWith("filename"))) {
 
				String[] name = filename.split("=");
 
				String finalFileName = name[1].trim().replaceAll("\"", "");
				return finalFileName;
			}
		}
		return "unknown";
	}

  这里,比较麻烦,要获得header,比如header是如下形式的,然后要再提取其中的文件名:
Content-Disposition=[form-data; name="file"; filename="filename.extension"]
   最后用writeFile写入磁盘.真麻烦呀,还是用spring mvc好.

2
  MultipartForm 的例子,  MultipartForm 中,将上传的文件中的属性配置到
POJO中,例子为:FileUploadForm 类,这个POJO类对应上传的文件类.

  

 import javax.ws.rs.FormParam;
import org.jboss.resteasy.annotations.providers.multipart.PartType;

public class FileUploadForm {

    public FileUploadForm() {
    }

    private byte[] data;

    public byte[] getData() {
        return data;
    }

    @FormParam("uploadedFile")
    @PartType("application/octet-stream")
    public void setData(byte[] data) {
        this.data = data;
    }

}

 import javax.ws.rs.FormParam;
import org.jboss.resteasy.annotations.providers.multipart.PartType;
 
public class FileUploadForm {
 
	public FileUploadForm() {
	}
 
	private byte[] data;
 
	public byte[] getData() {
		return data;
	}
 
	@FormParam("uploadedFile")
	@PartType("application/octet-stream")
	public void setData(byte[] data) {
		this.data = data;
	}
 
}
  

   处理部分就简单多了,可以这样:

Path("/file")
public class UploadFileService {

    @POST
    @Path("/upload")
    @Consumes("multipart/form-data")
    public Response uploadFile(@MultipartForm FileUploadForm form) {

        String fileName = "d:\\anything";

        try {
            writeFile(form.getData(), fileName);
        } catch (IOException e) {

            e.printStackTrace();
        }

        System.out.println("Done");

        return Response.status(200)
            .entity("uploadFile is called, Uploaded file name : " + fileName).build();

    }

Path("/file")
public class UploadFileService {
 
	@POST
	@Path("/upload")
	@Consumes("multipart/form-data")
	public Response uploadFile(@MultipartForm FileUploadForm form) {
 
		String fileName = "d:\\anything";
 
		try {
			writeFile(form.getData(), fileName);
		} catch (IOException e) {
 
			e.printStackTrace();
		}
 
		System.out.println("Done");
 
		return Response.status(200)
		    .entity("uploadFile is called, Uploaded file name : " + fileName).build();
 
	}

  即可.

  但总的感觉,REST有点蛋疼,上传个文件,用SPIRNG MVC或者其他方法都可以了,还用
REST这个方法?