Java实现表单提交（支持多文件同时上传）

发布时间：2020-12-14 14:35:21 所属栏目：Java 来源：网络整理

导读：在Android里面或者J2EE后台需要趴别人网站数据，模拟表单提交是一件很常见的事情，但是在Android里面要实现多文件上传，还要夹着普通表单字段上传，这下可能就有点费劲了，今天花时间整理了一个工具类，主要是借助于HttpClient，其实也很简单，看一下代码就

在Android里面或者J2EE后台需要趴别人网站数据，模拟表单提交是一件很常见的事情，但是在Android里面要实现多文件上传，还要夹着普通表单字段上传，这下可能就有点费劲了，今天花时间整理了一个工具类，主要是借助于HttpClient，其实也很简单，看一下代码就非常清楚了

HttpClient工具类：

HttpClientUtil.java

package cn.com.ajava.util;
import java.io.File;
import java.io.Serializable;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Map.Entry;
import org.apache.http.Consts;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.mime.MultipartEntityBuilder;
import org.apache.http.entity.mime.content.FileBody;
import org.apache.http.entity.mime.content.StringBody;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;

/**
 * HttpClient工具类
 * 
 * @author 曾繁添
 * @version 1.0
 */
public class HttpClientUtil
{
 public final static String Method_POST = "POST";
 public final static String Method_GET = "GET";
 /**
  * multipart/form-data类型的表单提交
  * 
  * @param form
  *   表单数据
  */
 public static String submitForm(MultipartForm form)
 {
  // 返回字符串
  String responseStr = "";
  // 创建HttpClient实例
  HttpClient httpClient = new DefaultHttpClient();
  try
  {
   // 实例化提交请求
   HttpPost httpPost = new HttpPost(form.getAction());
   // 创建MultipartEntityBuilder
   MultipartEntityBuilder entityBuilder = MultipartEntityBuilder.create();
   // 追加普通表单字段
   Map<String,String> normalFieldMap = form.getNormalField();
   for (Iterator<Entry<String,String>> iterator = normalFieldMap.entrySet().iterator(); iterator.hasNext();)
   {
    Entry<String,String> entity = iterator.next();
    entityBuilder.addPart(entity.getKey(),new StringBody(entity.getValue(),ContentType.create("text/plain",Consts.UTF_8)));
   }
   // 追加文件字段
   Map<String,File> fileFieldMap = form.getFileField();
   for (Iterator<Entry<String,File>> iterator = fileFieldMap.entrySet().iterator(); iterator.hasNext();)
   {
    Entry<String,File> entity = iterator.next();
    entityBuilder.addPart(entity.getKey(),new FileBody(entity.getValue()));
   }
   // 设置请求实体
   httpPost.setEntity(entityBuilder.build());
   // 发送请求
   HttpResponse response = httpClient.execute(httpPost);
   int statusCode = response.getStatusLine().getStatusCode();
   // 取得响应数据
   HttpEntity resEntity = response.getEntity();
   if (200 == statusCode)
   {
    if (resEntity != null)
    {
     responseStr = EntityUtils.toString(resEntity);
    }
   }
  } catch (Exception e)
  {
   System.out.println("提交表单失败，原因：" + e.getMessage());
  } finally
  {
   httpClient.getConnectionManager().shutdown();
  }
  return responseStr;
 }
 /** 表单字段Bean */
 public class MultipartForm implements Serializable
 {
  /** 序列号 */
  private static final long serialVersionUID = -2138044819190537198L;
  /** 提交URL **/
  private String action = "";
  /** 提交方式：POST/GET **/
  private String method = "POST";
  /** 普通表单字段 **/
  private Map<String,String> normalField = new LinkedHashMap<String,String>();
  /** 文件字段 **/
  private Map<String,File> fileField = new LinkedHashMap<String,File>();
  public String getAction()
  {
   return action;
  }
  public void setAction(String action)
  {
   this.action = action;
  }
  public String getMethod()
  {
   return method;
  }
  public void setMethod(String method)
  {
   this.method = method;
  }
  public Map<String,String> getNormalField()
  {
   return normalField;
  }
  public void setNormalField(Map<String,String> normalField)
  {
   this.normalField = normalField;
  }
  public Map<String,File> getFileField()
  {
   return fileField;
  }
  public void setFileField(Map<String,File> fileField)
  {
   this.fileField = fileField;
  }
  public void addFileField(String key,File value)
  {
   fileField.put(key,value);
  }
  public void addNormalField(String key,String value)
  {
   normalField.put(key,value);
  }
 }
}

服务器端实现文件上传、并且读取参数方法：（借助于Apache的fileupload组件实现，实现了获取表单action后面直接拼接参数、表单普通项目、文件项目三种字段获取方法）

后台我就直接写了一个Servlet，具体代码如下：

ServletUploadFile.java

package cn.com.ajava.servlet;
import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Enumeration;
import java.util.Iterator;
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.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
/**
 * 文件上传Servlet
 * @author 曾繁添
 */
public class ServletUploadFile extends HttpServlet
{
 private static final long serialVersionUID = 1L;
 // 限制文件的上传大小 1G
 private int maxPostSize = 1000 * 1024 * 10;
 public ServletUploadFile()
 {
 super();
 }
 @Override
 protected void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException
 {
 doPost(request,response);
 }
 protected void doPost(HttpServletRequest request,IOException
 {
 PrintWriter out = response.getWriter();
 String contextPath = request.getSession().getServletContext().getRealPath("/");
 String webDir = "uploadfile" + File.separator + "images" + File.separator;
 String systemPath = request.getContextPath();
 String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort()+ systemPath + "/";
 request.setCharacterEncoding("UTF-8");
 response.setContentType("text/html;charset=UTF-8");
 try
 {
  DiskFileItemFactory factory = new DiskFileItemFactory();
  factory.setSizeThreshold(1024 * 4); // 设置写入大小
  ServletFileUpload upload = new ServletFileUpload(factory);
  upload.setSizeMax(maxPostSize); // 设置文件上传最大大小
  System.out.println(request.getContentType());
  //获取action后面拼接的参数(如：http://www.baidu.com?q=android)
  Enumeration enumList = request.getParameterNames();
  while(enumList.hasMoreElements()){
  String key = (String)enumList.nextElement();
  String value = request.getParameter(key);
  System.out.println(key+"="+value);
  }
  //获取提交表单项目
  List listItems = upload.parseRequest(request);
  Iterator iterator = listItems.iterator();
  while (iterator.hasNext())
  {
  FileItem item = (FileItem) iterator.next();
  //非普通表单项目
  if (!item.isFormField())
  {
   //获取扩展名
   String ext = item.getName().substring(item.getName().lastIndexOf("."),item.getName().length());
   String fileName = System.currentTimeMillis() + ext;
   File dirFile = new File(contextPath + webDir + fileName);
   if (!dirFile.exists())
   {
   dirFile.getParentFile().mkdirs();
   }
   item.write(dirFile);
   System.out.println("fileName：" + item.getName() + "=====" + item.getFieldName() + " size： "+ item.getSize());
   System.out.println("文件已保存到： " + contextPath + webDir + fileName);
   //响应客户端请求
   out.print(basePath + webDir.replace("","/") + fileName);
   out.flush();
  }else{
   //普通表单项目
   System.out.println("表单普通项目："+item.getFieldName()+"=" + item.getString("UTF-8"));// 显示表单内容。item.getString("UTF-8")可以保证中文内容不乱码
  }
  }
 } catch (Exception e)
 {
  e.printStackTrace();
 } finally
 {
  out.close();
 }
 }
}

工具类、服务器端代码上面都贴出来了，具体怎么调用应该就不需要说了吧？封装的已经够清晰明了了

调用示例DEMO：

//创建HttpClientUtil实例
HttpClientUtil httpClient = new HttpClientUtil();
MultipartForm form = httpClient.new MultipartForm();
//设置form属性、参数
form.setAction("http://192.168.1.7:8080/UploadFileDemo/cn/com/ajava/servlet/ServletUploadFile");
File photoFile = new File(sddCardPath+"//data//me.jpg");
form.addFileField("photo",photoFile);
form.addNormalField("name","曾繁添");
form.addNormalField("tel","15122946685");
//提交表单
HttpClientUtil.submitForm(form);

最后说明一下jar问题：

要是android里面应用的话，需要注意一下额外引入httpmime-4.3.1.jar（我当时下的这个是最高版本了），至于fileUpload的jar，直接去apache官网下载吧

以上就是本文的全部内容，希望本文的内容对大家的学习或者工作能带来一定的帮助，同时也希望多多支持编程小技巧！

（编辑：李大同）

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