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代码：
package com.github.reston.servlet;
import java.io.file;
import java.io.fileoutputstream;
import java.io.ioexception;
import java.io.printwriter;
import java.util.iterator;
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 class ajaxupload extends httpservlet{
@override
public void init(servletconfig config) throws servletexception{
// todo auto-generated method stub
super.init(config);
}
@override
protected void service(httpservletrequest request,httpservletresponse response) throws servletexception,ioexception{
response.setcontenttype("text/html");
request.setcharacterencoding("utf-8");
boolean ismultipart=servletfileupload.ismultipartcontent(request);
string basepath=getservletcontext().getrealpath("/upload");
file basedirectory=new file(basepath);
string filename="";
long start=0;
if(!basedirectory.isdirectory()) basedirectory.mkdirs();
if(ismultipart){
try{
fileitemfactory factory=new diskfileitemfactory();
servletfileupload upload=new servletfileupload(factory);
@suppresswarnings("unchecked") list fileitems=upload.parserequest(request);
for(fileitem i:fileitems){
if(i.isformfield()){
string name=i.getfieldname();
string value=i.getstring();
if(name.equals("start"))start=long.parselong(i.getstring());
}
}
for(fileitem item:fileitems){
if(item.isformfield()) continue;
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(exception e){
}
}
}
private file createfile(string path,string name) throws ioexception{
file tmp=new file(path,name);
if(!tmp.exists()){
tmp.createnewfile();
}
return tmp;
}
private boolean mkdir(string path){
boolean result=true;
file tmp=new file(path);
if(!tmp.isdirectory()){
result=tmp.mkdirs();
}
return result;
}
}
2、java代码：
var ajaxupload = function(e) {
/**
* e url method data success error
*/
var xmlhttprequest;
if (window.xmlhttprequest) {
xmlhttprequest = new xmlhttprequest();
if (xmlhttprequest.overridemimetype) {
xmlhttprequest.overridemimetype("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]);
break;
} catch (e) {
return;
}
}
}
if (xmlhttprequest == undefined || xmlhttprequest == null) {
alert("xmlhttprequest对象创建失败！！");
return;
} 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!!!");
return;
}
if (e.url == null || e.url == undefined) {
e.alert("http的请求地址必须设置！");
return;
}
}
this.xmlhttp.onreadystatechange = function() {
if (this.readystate == 4) {
if (this.status == 200) {
var responsetext = this.responsetext;
var responsexml = this.reponsexml;
if (e.success == undefined || e.success == null) {
alert("没有设置处理数据正确返回的方法");
alert("返回的数据：" + responsetext);
} else {
e.success(responsetext, 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！");
alert("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="
";
var filename = getfilename(e.id);
this.xmlhttp.open(e.method, e.url, true);
var data = new formdata(document.getelementbyid("output"));
data.append("name", filename);
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);
}
function 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);
}
function getfilesize(id) {
return document.getelementbyid(id).files[0].size;
}
3、html代码：
请选择要上传的文件(小于1g)
function test(){
ajaxupload({
id : "upload",
url : "/pcc/reston/ajaxupload",
method : "post",
data : {start:0},
success : function(e) {
var l=json.parse(e).length;
ajaxupload({
id : "upload",
url : "/pcc/reston/ajaxupload",
method : "post",
data : {start:l},
success : function(e) {
},
error : function(e) {
console.log(e);
}
});
},
error : function(e) {
console.log(e);
}
});
}
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