cos是o'rrilly公司开发的一款用于http上传文件的opensource组件。下面通过本文给大家分享使用cos实现文件上传功能，感兴趣的朋友一起看看吧
cos是o'rrilly公司开发的一款用于http上传文件的opensource组件
需要cos.jar
cos上传文件很简单，比fileupload还简单：但是上传最大我试了试，是800多兆，超过直接崩溃：
java.io.ioexception: posted content length of 1627105576 exceeds limit of 889192448 --->byte，800多m
只需一个servelt即可：
package com.lhy.upload;
import java.io.file;
import java.io.fileoutputstream;
import java.io.ioexception;
import java.io.outputstream;
import java.io.printwriter;
import java.util.enumeration;
import java.util.uuid;
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 com.oreilly.servlet.multipartrequest;
import com.oreilly.servlet.multipart.filerenamepolicy;
/**
* cosservlet
* 在cos中就一个类，
* multipartrequest它是request的包装类。
*/
@webservlet(name="cosservlet",urlpatterns="/cosservlet")
public class cosservlet extends httpservlet{
@override
protected void dopost(httpservletrequest req, httpservletresponse resp) throws servletexception, ioexception {
//第一步，声明文件的保存目录
string path = getservletcontext().getrealpath("/up");
//第二步：文件上传
//声明文件重新命名策略,默认的不行不能重命名，自己实现filerenamepolicy接口
// filerenamepolicy rename = new defaultfilerenamepolicy();
multipartrequest multireq = new multipartrequest(req, path, 1024*1024*100, "utf-8",new myrename());
//输出所上传的文件的信息
enumeration filenames = multireq.getfilenames();
while(filenames.hasmoreelements()){
string name = (string)filenames.nextelement();
file file = multireq.getfile(name);//得到上传的文件
if(null != file){
string filename = multireq.getfilesystemname(name); //取得文件名
string contenttype = multireq.getcontenttype(name);//类型
system.out.println("上传的文件: " +filename+"， 文件类型: "+contenttype);
}
}
//输出所提交的表单中其它文本输入域的值
enumeration formvalue = multireq.getparameternames();
while(formvalue.hasmoreelements()){
string param = (string)formvalue.nextelement();
string value = multireq.getparameter(param);
system.out.println(value);
}
//第三步：如果知道input的name，还可以直接获取信息，
/*resp.setcontenttype("text/html;charset=utf-8");
printwriter out = resp.getwriter();
out.print("文件名称1:"+multireq.getoriginalfilename("img1"));
out.print("<br/>新名称:"+multireq.getfilesystemname("img1"));
out.print("<br/>类型1:"+multireq.getcontenttype("img1"));
out.print("<br/>大小1："+multireq.getfile("img1").length());
out.print("<br/>说明:"+multireq.getparameter("desc1"));
if(multireq.getcontenttype("img1").contains("image/")){
out.print("<img width='300px' height='200px' src='"+req.getcontextpath()+"/up/"+multireq.getfilesystemname("img1")+"'></img>");
}
out.print("<hr/>");
out.print("文件名称2:"+multireq.getoriginalfilename("img2"));
out.print("<br/>类型2:"+multireq.getcontenttype("img2"));
out.print("<br/>大小2："+multireq.getfile("img2").length());
out.print("<br/>说明2:"+multireq.getparameter("desc2"));
//
out.print("<hr/>");
out.print("文件名称3:"+multireq.getoriginalfilename("img3"));
out.print("<br/>类型3:"+multireq.getcontenttype("img3"));
out.print("<br/>大小3："+multireq.getfile("img3").length());
out.print("<br/>说明3:"+multireq.getparameter("desc3"));*/
}
}
/**
* 重命名策略，
*/
class myrename implements filerenamepolicy{
@override
public file rename(file file) {
string filename = file.getname();
string extname = filename.substring(filename.lastindexof("."));
string uuid = uuid.randomuuid().tostring().replace("-","");
string newname = uuid+extname;//abc.jpg
file = new file(file.getparent(),newname);
return file;
}
}
表单：
<form action="<c:url value='/cosservlet'/>" method="post"
enctype="multipart/form-data">
file1：<input type="file" name="img1"><br /> 说明1：
<input type="text" name="desc1"><br />
file2：<input type="file" name="img2"><br/>
说明2：<input type="text" name="desc2"><br/>
file3：<input type="file" name="img3"><br/>
说明3：<input type="text" name="desc3"><br/>
<input type="submit" />
</form>
启动上传：
服务端：
总结
以上就是java中关于使用cos实现文件上传功能的详解的详细内容。