servlet 用组件上传文件
简单的上传图片
1.在index.jsp文件中的body之间加
<form action="/Test/servlet/RegisterServlet" method="post" enctype="multipart/form-data"> <br> 头像:<input type="file" name="userHead"> <br> <input type="submit" value="提交"> </form>
2.在Test项目中创建servlet类命名为 RegisterServlet
在servlet文件中doPost方法中加
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
response.setCharacterEncoding("utf-8");
PrintWriter out = response.getWriter();
//保存路径
String Path= null;
//判断请求消息中的内容是否是“multipart/form-data”类型
boolean multipart = ServletFileUpload.isMultipartContent(request);
if (multipart) {
FileItemFactory factory = new DiskFileItemFactory();
ServletFileUpload upload = new ServletFileUpload(factory);
try {
List<FileItem> fileItems = upload.parseRequest(request);
//将图片保存到指定文件夹下
File userHead = uploadHead(fileItems, "userHead");
if(userHead!=null && userHead.exists())
{
String fullPath=userHead.getPath();
String[] paths=fullPath.split("/");
String fileName=paths[paths.length-1];
//拼出网络路径
Path= SystemConfig.API_BASE_URL_HEAD+fileName;
}
}catch (FileUploadException e) {
e.printStackTrace();
}
}
//直接在网页中打印图片
// out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
// out.println("<HTML>");
// out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>");
// out.println(" <BODY>");
// out.println(" <img src=\""+Path+"\"> ");
// out.println(" </BODY>");
// out.println("</HTML>");
// out.flush();
// out.close();
}
3.将图片保存到指定文件夹
把方法加到RegisterServlet类中
public File uploadHead(List<FileItem> items, String name) {
for (FileItem item : items) {
if (!item.isFormField() && name.equals(item.getFieldName())) {
NameValuePair pair = FileHelper.getTempFile(item.getName());
File file = new File(pair.getKey());
if (!file.exists()) {
try {
file.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
}
try {
item.write(file);
} catch (Exception e) {
e.printStackTrace();
}
return file;
}
}
return null;
}
4.定义路径宏定义 SystemConfig类中
public class SystemConfig {
public static final String API_BASE_URL_HEAD="http://127.0.0.1:8080/Test/img/";//图片的访问地址
public static final String API_BASE_PATH_HEAD="/Users/ty/Desktop/apache-tomcat-7.0.50/webapps/Test/img/";//要存储的路径
}
图片一定要放到tomcat下相应项目的文件夹下（不然会访问不到！）
5.FileHelper.java文件
public class FileHelper {
public static NameValuePair getTempFile(String name) {
//String path = System.currentTimeMillis() + "." + getEndWith(name);
String path=getFileShortName(name);
String key = SystemConfig.API_BASE_PATH_HEAD + path;
return new NameValuePair(key, path);
}
public static String getEndWith(String fileName) {
int i = fileName.lastIndexOf(".");
if (i >= 0) {
return fileName.substring(i + 1, fileName.length());
}
return "";
}
public static String getFileShortName(String fileName)
{
String[] strs=fileName.split("/");
return strs[strs.length-1];
}
}6.
NameValuePair.java文件
public class NameValuePair {
private String key;
private String value;
public NameValuePair(String key, String value) {
this.key = key;
this.value = value;
}
public String getKey(){
return key;
}
public String getValue(){
return value;
}
public String toString(){
return "key="+key+";value="+value;
}
}
7.一定要加入文件上传组件
8.看在指定的文件夹中是否有 所传的文件或图片