urlconnection类给应用程序和web资源之间架设起了通信的桥梁，这些web资源通常是通过url来标记的,本文将讲述如何使用httpurlconnection来访问web页面(发送数据流)和读取数据流。
在servlet中对于需要用post方式(get会暴露参数)写入参数的时候就用到了httpurlconnection.
请求的servlet，也可以写入main方法中进行测试
package com;
import java.io.bufferedreader;
import java.io.ioexception;
import java.io.inputstreamreader;
import java.io.outputstream;
import java.io.outputstreamwriter;
import java.net.httpurlconnection;
import java.net.url;
import javax.servlet.servletexception;
import javax.servlet.http.httpservlet;
import javax.servlet.http.httpservletrequest;
import javax.servlet.http.httpservletresponse;
@suppresswarnings("serial")
public class ioservlet extends httpservlet
{
/** *//**
* 对于主动请求其它接口的参数流写入(post方式)
*/
public void doget(httpservletrequest request, httpservletresponse response)
throws servletexception, ioexception
{
system.out.println("begin send");
string inputparam = ""1.0\" encoding=\"utf-8\"?>爱心天使26";
url url = null;
httpurlconnection httpconn = null;
outputstream output = null;
outputstreamwriter outr = null;
url = new ;
httpconn = (httpurlconnection) url.openconnection();
httpurlconnection.setfollowredirects(true);
httpconn.setdooutput(true);
httpconn.setrequestmethod("post");
httpconn.setrequestproperty("content-type", "text/xml");
httpconn.connect();
output = httpconn.getoutputstream();
outr = new outputstreamwriter(output);
// 写入请求参数
outr.write(inputparam.tostring().tochararray(), 0, inputparam
.tostring().length());
outr.flush();
outr.close();
system.out.println("send ok");
int code = httpconn.getresponsecode();
system.out.println("code " code);
system.out.println(httpconn.getresponsemessage());
//读取响应内容
string scurrentline = "";
string stotalstring = "";
if (code == 200)
{
java.io.inputstream is = httpconn.getinputstream();
bufferedreader reader = new bufferedreader(
new inputstreamreader(is));
while ((scurrentline = reader.readline()) != null)
if (scurrentline.length() > 0)
stotalstring = stotalstring scurrentline.trim();
} else
{
stotalstring = "远程服务器连接失败,错误代码:" code;
}
system.out.println("response:" stotalstring);
}
public void dopost(httpservletrequest request, httpservletresponse response)
throws servletexception, ioexception
{
this.doget(request, response);
}
}
readservlet(相当于被请求的服务器):
package com;
import java.io.ioexception;
import java.io.printwriter;
import javax.servlet.servletexception;
import javax.servlet.servletinputstream;
import javax.servlet.http.httpservlet;
import javax.servlet.http.httpservletrequest;
import javax.servlet.http.httpservletresponse;
@suppresswarnings("serial")
public class readservlet extends httpservlet
{
public void doget(httpservletrequest request, httpservletresponse response) throws ioexception
{
system.out.println("begin read");
servletinputstream instream = request.getinputstream(); // 取http请求流
int size = request.getcontentlength(); // 取http请求流长度
byte[] buffer = new byte[size]; // 用于缓存每次读取的数据
byte[] in_b = new byte[size]; // 用于存放结果的数组
int count = 0;
int rbyte = 0;
// 循环读取
while (count < size)
{
rbyte = instream.read(buffer); // 每次实际读取长度存于rbyte中 sflj
for (int i = 0; i < rbyte; i)
{
in_b[count i] = buffer[i];
}
count = rbyte;
}
system.out.println("result:" new string(in_b,0,in_b.length));
response.setcontenttype("text/html");
//注意响应中文数据时要设置
response.setcharacterencoding("gbk");
printwriter out = response.getwriter();
//回与响应数据
out.write("您已经请求成功，这是响应数据!");
}
public void dopost(httpservletrequest request, httpservletresponse response)
throws servletexception, ioexception
{
this.doget(request, response);
}
}
打开页面:http://localhost:8888/iotest/ioservlet
你会在后台看到如下输出说明你已经成功了:
begin send
send ok
begin read
result:xml version="1.0" encoding="utf-8"?><page><username>爱心天使usernaem><age>26age>page>
code 200
ok
response:您已经请求成功，这是响应数据!
源码下载: