java使用http实现文件下载学习示例
package com.hongyuan.test;
import java.io.file;
import java.io.fileoutputstream;
import java.io.ioexception;
import java.io.inputstream;
import java.io.outputstream;
import java.net.httpurlconnection;
import java.net.malformedurlexception;
import java.net.url;
import java.net.urldecoder;
public class filedownload {
public static final string local_path="d:/";
public static void main(string[] args) {
//待下载文件地址
string fileurl="http://211.162.55.16/cdn.baidupcs.com/file/6a73dab7c03023a9835cc737f447674d?xcode=af6ffdc43a44169bac968d32c4bd420084a9a97c308112c9&fid=3255571826-250528-130564002&time=1397293108&sign=fdtaxer-dcb740ccc5511e5e8fedcff06b081203-mqkoerdtxpyqwwyjki%2bxkjpxn5k%3d&to=cb&fm=n,b,u,nc&newver=1&expires=1397297563&rt=sh&r=854979042&logid=1751715936&sh=1&vuk=3255571826&fn=web%e7%a8%8b%e5%ba%8f%e8%ae%be%e8%ae%a1%20%e7%ac%ac5%e7%89%88.pdf&wshc_tag=0&wsiphost=ipdbm";
inputstream in=null;
outputstream out=null;
httpurlconnection conn=null;
string filename=null;
try {
//初始化连接
url url=new url(fileurl);
conn = (httpurlconnection) url.openconnection();
conn.setdoinput(true);
conn.setdooutput(true);
//获取文件名
string disposition=conn.getheaderfield("content-disposition");
if(disposition!=null&&!"".equals(disposition)){
//从头中获取文件名
filename=disposition.split(";")[1].split("=")[1].replaceall("\"","");
}else{
//从地址中获取文件名
filename=fileurl.substring(fileurl.lastindexof("/")+1);
}
if(filename!=null&&!"".equals(filename)){
//文件名解码
filename=urldecoder.decode(filename, "utf-8");
}else{
//如果无法获取文件名,则随机生成一个
filename="file_"+(int)(math.random()*10);
}
//读取数据
if(conn.getresponsecode()==httpurlconnection.http_ok){
byte[] buffer=new byte[2048];
in = conn.getinputstream();
out=new fileoutputstream(new file(local_path,filename));
int count=0;
int finished=0;
int size=conn.getcontentlength();
while((count=in.read(buffer))!=-1){
if(count!=0){
out.write(buffer,0,count);
finished+=count;
system.out.printf("########################################---->%1$.2f%%\n",(double)finished/size*100);
}else{
break;
}
}
}
} catch (malformedurlexception e) {
e.printstacktrace();
} catch (ioexception e) {
e.printstacktrace();
}finally{
try {
out.close();
in.close();
conn.disconnect();
} catch (ioexception e) {
e.printstacktrace();
}
}
}
}
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