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);