java 上传图片 cxf,servlet,spring 标准方式

1.标准的java上传方式

package com.weds.common.pay.servlet;
import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.json.JSONObject;

import com.weds.framework.core.common.model.JsonResult;

public class UploadServlet extends HttpServlet {

	/**
	 * Destruction of the servlet. <br>
	 */
	public void destroy() {
		super.destroy(); // Just puts "destroy" string in log
		// Put your code here
	}

	/**
	 * The doGet method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to get.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		response.setContentType("text/html;charset=utf-8");
		request.setCharacterEncoding("utf-8");
		response.setCharacterEncoding("utf-8");
		PrintWriter out = response.getWriter();
		//实现上传的类
		DiskFileItemFactory factory = new DiskFileItemFactory();//磁盘对象
		
		ServletFileUpload upload = new ServletFileUpload(factory);//声明解析request对象
		upload.setFileSizeMax(2*1024*1024);//设置每个文件最大为2M
		upload.setSizeMax(4*1024*1024);//设置一共最多上传4M
		
		try {
			List<FileItem> list = upload.parseRequest(request);//解析
			for(FileItem item:list){//判断FileItem类对象封装的数据是一个普通文本表单字段，还是一个文件表单字段，如果是普通表单字段则返回true，否则返回false。
				if(!item.isFormField()){
					//获取文件名
					String fileName = item.getName();
					//获取服务器端路径
					String file_upload_loader =this.getServletContext().getRealPath("");
					System.out.println("上传文件存放路径:"+file_upload_loader);
					//将FileItem对象中保存的主体内容保存到某个指定的文件中。
					item.write(new File(file_upload_loader+File.separator+fileName));
				}else{
					if(item.getFieldName().equalsIgnoreCase("username")){
						String username = item.getString("utf-8");//将FileItem对象中保存的数据流内容以一个字符串返回
						System.out.println(username);
					}
					if(item.getFieldName().equalsIgnoreCase("password")){
						String password = item.getString("utf-8");
						System.out.println(password);
					}
				}
			}
			//返回响应码（ResultCode）和响应值（ResultMsg）简单的JSON解析
			JsonResult jsonResult=new JsonResult();
			JSONObject json = new JSONObject();
			JSONObject jsonObject = new JSONObject();
			json.put("ResultCode",jsonResult.getCode());
			json.put("ResultMsg",jsonResult.getMsg());
			jsonObject.put("upload",json);
			//System.out.println(jsonObject.toString());
			out.print(jsonObject.toString());
			
		} catch (FileUploadException e) {
			e.printStackTrace();
		} catch (Exception e) {
			e.printStackTrace();
		}finally{
			out.close();
		}
	}

	/**
	 * The doPost method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to post.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		doGet(request,response);
	}

	/**
	 * Initialization of the servlet. <br>
	 *
	 * @throws ServletException if an error occurs
	 */
	public void init() throws ServletException {
		// Put your code here
	}

}

然后配置servlet

   <servlet>
        <servlet-name>upload</servlet-name>
        <servlet-class>com.weds.common.pay.servlet.UploadServlet</servlet-class>
        <load-on-startup>3</load-on-startup>
   </servlet>
   <servlet-mapping>
       <servlet-name>upload</servlet-name>
       <url-pattern>/upload</url-pattern>
   </servlet-mapping>

2. 标准java 通过 request的方式 笔者用的是spring + Apache cxf rest

	接口定义

	@POST  
	@Path("/upload")
	@Consumes(MediaType.MULTIPART_FORM_DATA)//当前方法接收的参数类型
    public String uploadFile();

接收实现

@Override
	public String uploadFile() {
		HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder
				.getRequestAttributes()).getRequest();
		// 实现上传的类
		DiskFileItemFactory factory = new DiskFileItemFactory();// 磁盘对象
		ServletFileUpload upload = new ServletFileUpload(factory);// 声明解析request对象
		upload.setFileSizeMax(2 * 1024 * 1024);// 设置每个文件最大为2M
		upload.setSizeMax(4 * 1024 * 1024);// 设置一共最多上传4M
		try {
			List<FileItem> list = upload.parseRequest(request);// 解析
			for (FileItem item : list) {// 判断FileItem类对象封装的数据是一个普通文本表单字段，还是一个文件表单字段，如果是普通表单字段则返回true，否则返回false。
				if (!item.isFormField()) {
					// 获取文件名
					String fileName = item.getName();
					// 获取服务器端路径
					String file_upload_loader = request.getServletContext()
							.getRealPath("");
					System.out.println("上传文件存放路径:" + file_upload_loader);
					// 将FileItem对象中保存的主体内容保存到某个指定的文件中。
					item.write(new File(file_upload_loader + File.separator
							+ fileName));
				} else {
					if (item.getFieldName().equalsIgnoreCase("username")) {
						String username = item.getString("utf-8");// 将FileItem对象中保存的数据流内容以一个字符串返回
						System.out.println(username);
					}
					if (item.getFieldName().equalsIgnoreCase("password")) {
						String password = item.getString("utf-8");
						System.out.println(password);
					}
				}
			}
		} catch (FileUploadException e) {
			e.printStackTrace();
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			// out.close();
		}
		return "ok";
	}

注意这里获取request的时候，必须用上面的写法，通过 @Autowired注入获取request的方式在这里是不能用的，原因不详，求大神指点。

3.cxf rest 风格上传实现 @Multipart的 type是可以省略的，下面的写法，尤其是image，其实限制了图片的类型，要求很严格。

/** 
     * 表单提交，文件上传 
     * @return 
     */  
    @POST  
    @Path("/uploadimage")  
    @Consumes("multipart/form-data")  
    public String uploadFileByForm(  
            @Multipart(value="id",type="text/plain")String id,  
            @Multipart(value="name",type="text/plain")String name,  
            @Multipart(value="file",type="image/png")Attachment image);  

接口的实现：

实现方式很多种：

如下是第一种，这是最简单的方式，直接取出流，然后读取

@Override
	public String uploadFileByForm(
			@Multipart(value = "id", type = "text/plain") String id,
			@Multipart(value = "name", type = "text/plain") String name,
			@Multipart(value = "file", type = "image/png") Attachment image) {
		try {
			OutputStream out = new FileOutputStream(new File("d:\a.png"));
			image.getDataHandler().writeTo(out);
			out.close();
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return "ok";
	}

第二种：

	@Override
	public String uploadFileByForm(
			@Multipart(value = "id", type = "text/plain") String id,
			@Multipart(value = "name", type = "text/plain") String name,
			@Multipart(value = "file", type = "image/png") Attachment image) {
		System.out.println("id:" + id);
		System.out.println("name:" + name);
		DataHandler dh = image.getDataHandler();
		try {
			InputStream ins = dh.getInputStream();
			writeToFile(ins,"d:\"+ new String(dh.getName().getBytes("iso-8859-1"),"utf-8"));
		} catch (Exception e) {
			e.printStackTrace();
		}
		return "ok";
	}

	private void writeToFile(InputStream ins, String path) {		
		try {
			OutputStream out = new FileOutputStream(new File(path));
			byte[] bytes = new byte[1024];
			while (ins.read(bytes) != -1) {
				out.write(bytes);
			}
			out.flush();
			out.close();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

当然 writeToFile方法也可以这么实现：	

private void writeToFile(InputStream ins, String path) {
		try {
			OutputStream out = new FileOutputStream(new File(path));
			int read = 0;
			byte[] bytes = new byte[1024];
			while ((read = ins.read(bytes)) != -1) {
				out.write(bytes, 0, read);
			}
			out.flush();
			out.close();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

注意：笔者在用cxf rest做上传的时候还遇到了个问题，折腾了半天：

笔者写了个cxf的Interceptor 拦截器，实现了AbstractPhaseInterceptor<Message>，用来拦截客户端传过来的数据，做数据处理，比如加解密，身份认证，等等，但是笔者有把客户端传过来的流出来分析了之后，在回写进去的操作，这么一来就发生了一个问题，这里处理的应该是字符流，而上传图片的时候是文件流，流只能读取一次，笔者处理完了之后，cxf的接收实现类里，在执行上面的读取文件流的图片的时候，就出现了个问题，笔者原本的图片是122k，由于拦截器的原因，这时候把图片写到文件里变成了200k，然后图片就打不开了，要注意！！！

另外：writeToFile(ins,"d:\"+ new String(dh.getName().getBytes("iso-8859-1"),"utf-8"));，这里，红色部分是为了防止客户端上传的图片中文名字乱码，其实没啥鸟用，因为我们的文件流上传之后，一般会用GUID 代替原来的文件名字。

4.服务端 rest接口，直接接收客户端的流

	/** 
     * 表单提交，文件上传 
     * @return 
     */  
    @POST  
    @Path("/uploadimage")  
    @Consumes("application/binary")  
    public String uploadFileByForm(InputStream inputStream);