本文实例为大家分享了java实现文件上传的具体代码，具体内容如下
1 java：：
com.github.reston.servlet;导入java.io.file; import java.io.fileOutputstream; import java.io.io.ioexception; import java.io.printwriter; import java java.util.itel.itel.terrator; import java.util.list; import javax.servlet.ServletConfig;import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;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.FileItemFactory;import org.apache.commons.fileupload.disk.DiskFileItemFactory;import org.apache.commons.fileupload.servlet.ServletFileUpload;import org.apache.commons.io.ioutils; @webservlet（“/ajaxupload”）public类ajaxupload扩展了httpservlet {@override public void init（servletConfig config）抛出servletException {// todo auto-nato auto-generated auto-generated auto-generated方法stub suble suble.init（config）; } @Override受保护的void Service（httpservletrequest请求，httpservletresponse响应）抛出ServletException，ioexception {wendment.setContentType（“ text/html”）; request.setCharacterEncoding（“ UTF-8”）; boolean ismultipart = servletfileupload.ismultipartcontent（请求）;字符串basepath = getservletContext（）。getRealPath（“/upload”）; File daseRectory = new File（basepath）;字符串文件名=“”;长启动= 0; if（！spedieRectory.isdirectory（））laseectory.mkdirs（）;如果（ismultipart）{尝试{fileItemFactory Factory = new DiskFileItemFactory（）; ServletFileUpload上传=新的ServletFileUpload（工厂）; @suppresswarnings（“ UNACKECT”）list <FileItem> fileItems = upload.parserequest（request）; for（fileItem i：fileItems）{if（i.isformfield（））{字符串name = i.getFieldName（）;字符串值= i.getString（）; if（name.equals（“ start”））start = long.parselong（i.getString（））; }} for（fileItem item：fileItems）{if（item.isformfield（））继续； filename = item.getFieldName（）; if（mkdir（basepath））{file fileonserver = createfile（basepath，filename）; if（fileonServer.length（）== 0）{fileOutputStream fos = new fileOutputStream（fileonServer，true）; ioutils.copy（item.getInputStream（），fos）; } if（start> 0）{fileOutputStream fos = new fileOutputStream（fileonServer，true）; ioutils.copy（item.getInputStream（），fos）; } printWriter pw = response.getWriter（）; pw.write（“ {/” length/“”：/“”+fileonserver.length（）+“/“}”）; pw.flush（）; }}}} catch（异常E）{}}} private file createfile（字符串路径，字符串名称）抛出ioexception {file tmp = new file（path，name）;如果（！tmp.exists（））{tmp.createnewfile（）; }返回TMP; } private boolean mkdir（string path）{boolean result = true;文件tmp =新文件（path）;如果（！tmp.isdirectory（））{结果= tmp.mkdirs（）; }返回结果; }}}2，java：：
var ajaxupload = function（e）{ / ** * e url方法数据成功错误 * / var xmlhttprequest; if（window.xmlhttprequest）{xmlhttprequest = new xmlhttprequest（）; if（xmlhttprequest.overridemeType）{xmlhttprequest.overridememetype（“ text/xml”）; }}} else if（window.activexobject）{var activename = [“ msxml2.xmlhttp”，“ microsoft.xmlhttp”]; for（var i = 0; i <activename.length; i ++）{try {xmlhttprequest = new ActiveXobject（activename [i]）;休息; } catch（e）{return; }}} if（xmlhttprequest == undefined || xmlhttprequest == null）{arter（“ xmlhttprequest 对象创建失败！！”）;返回; } else {this.xmlhttp = xmlhttprequest; } var file = document.getElementById（e.id）; if（this.xmlhttp！= undefined && this.xmlhttp！= null）{e.method = e.method.touppercase（）; if（e.Method！=“ get” && e.method！=“ post”）{alert（“ http的请求方法必须为get或post !!!”）;返回; } if（e.url == null || e.url == undefined）{e.Alert（“ http 的请求地址必须设置！”）;返回; }} this.xmlhttp.onreadyStateChange = function（）{if（this.dreadystate == 4）{if（this.status == 200）{var ponsepteText = this.responseText; var Responsexml = this.reponsexml; if（e.success == undectined || e.success == null）{alert（“没有设置处理数据正确返回的方法”）;警报（“返回的数据：” + ponsponseText）; } else {e.Success（ponsponseText，responsexml）; }} else {if（e.Error == undefined || e.error == null）{alert（“ 没有设置处理数据返回失败的处理方法！”）;警报（“ http的响应码：“ + this.status +”，响应码的文本信息：“ + this.statustext）; } else {e.Error（this.status，this.statustext）; }}}} // var formhtm =“ <form id ='output'enctype ='multipart/form-data'> </form>”; var filename = getFilename（e.id）; this.xmlhttp.open（e.method，e.url，true）; var data = new FormData（document.getElementById（“ output”））; data.append（“名称”，文件名）; data.append（“ start”，e.data.start）; data.append（fileName，document.getElementById（e.id）.files [0] .slice（e.data.start，getFilesize（e.id）））; this.xmlhttp.send（data）;}函数getfileName（id）{var path = document.getElementById（id）.value var pos1 = path.lastIndexof（'/'/'）; var pos2 = path.lastIndexof（'//'）; var pos = math.max（pos1，pos2）; return path.substring（pos + 1）;}函数getfilesize（id）{return document.getElementById（id）.files [0] .size;}3 html：：
<！doctype html> <html> <head> <meta http-equiv =“ content-type” content =“ text/html; charset = utf-8”> <script type =“ text/javascript” text/javascript“ src =“ src =” src =“ test.js”> value =“上传”/> <span>请选择要上传的文件（小于1G）</span> <input type =“ button” value =“上传” onclick =“ test（）;”/> <form id =“输出” enctype =“ multipart/form-data/form> </form> </form> </form> </form> </form> </form> </form <script> <script>函数test（） “/pcc/reston/ajaxupload”，方法：“ post”，数据：{start：0}，成功：函数（e）{var l = json.parse（e）.length; ajaxupload; ajaxupload; }，错误：函数（e）{console.log（e）;};}; } </script> </body> </html>以上就是本文的全部内容，Java程序设计有所帮助。