try
{
URL	url = new URL("https://www.baidu.com/");
HttpURLConnection conn = (HttpURLConnection)url.openConnection();
conn.setDoOutput(true);
//确定 向外输出数据
//请求头
conn.setRequestProperty("head", "xxx");
//请求体
OutputStream out = conn.getOutputStream();
out.write("data=xxx".getBytes()); //写入缓存 当getResponseCode时候，请求
//响应数据 read response
int code = conn.getResponseCode();//真正请求!
String headerField = conn.getHeaderField("server");
System.out.println(code);
System.out.println(headerField);
//响应体
InputStream is = conn.getInputStream();
int len = 0;
byte buff[] =new byte[1024];
while ((len=is.read(buff))>0)
{
System.out.println(new String(buff,0,len));
}
} catch (Exception e)
{
e.printStackTrace();
}
}

文件上传：

1.目录隐藏
2.文件名不重复uuid
3.文件分目录存储

	/**
* 文件上传的方法
*
* @param path
*
路径
* @param fileName
*
原文件名
* @param srcFile
*
原文件
* @return 路径 + 新文件名
* @throws Exception
*/
public static String upload(String path, String fileName, File srcFile) throws Exception
{
/** 获取项目的部署路径 + 文件存放路径 */
String realPath = ServletActionContext.getServletContext().getRealPath(path);
/** 生成的新的文件名 */
String newFileName = UUID.randomUUID().toString() + "." + FilenameUtils.getExtension(fileName); // a.jpg
/** 文件拷贝 */
FileUtils.copyFile(srcFile, new File(realPath + "/" + newFileName));
System.out.println(realPath + "/" + newFileName);
return path + "/" + newFileName;// 147d65c3-5c97-4922-a3e5-8645e83672e0
}
/**
* 删除文件
*
* @param oldUrl
*
旧文件的URL
*/
public static void delete(String oldUrl)
{
/** 获取项目的部署路径 */
String realPath = ServletActionContext.getServletContext().getRealPath("/");
File file = new File(realPath + oldUrl);
if (file != null && file.isFile())
{
file.delete();
}
}

	/**
* 文件上传
*
* @param filePath
* @param accessToken
* @param type
* @return
* @throws IOException
* @throws NoSuchAlgorithmException
* @throws NoSuchProviderException
* @throws KeyManagementException
*/
public static String upload(String filePath, String url) throws Exception
{
File file = new File(filePath);
if (!file.exists() || !file.isFile())
{
throw new IOException("文件不存在");
}
// String url = UPLOAD_URL.replace("ACCESS_TOKEN",
// accessToken).replace("TYPE",type);
URL urlObj = new URL(url);
// 连接
HttpURLConnection con = (HttpURLConnection) urlObj.openConnection();
con.setRequestMethod("POST");
con.setDoInput(true);
con.setDoOutput(true);
con.setUseCaches(false);
// 设置请求头信息
con.setRequestProperty("Connection", "Keep-Alive");
con.setRequestProperty("Charset", "UTF-8");
// 设置边界
String BOUNDARY = "----------" + System.currentTimeMillis();
con.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + BOUNDARY);
StringBuilder sb = new StringBuilder();
sb.append("--");
sb.append(BOUNDARY);
sb.append("rn");
sb.append("Content-Disposition: form-data;name="file";filename="" + file.getName() + ""rn");
sb.append("Content-Type:application/octet-streamrnrn");
byte[] head = sb.toString().getBytes("utf-8");
// 获得输出流
OutputStream out = new DataOutputStream(con.getOutputStream());
// 输出表头
out.write(head);
// 文件正文部分
// 把文件已流文件的方式 推入到url中
DataInputStream in = new DataInputStream(new FileInputStream(file));
int bytes = 0;
byte[] bufferOut = new byte[1024];
while ((bytes = in.read(bufferOut)) != -1)
{
out.write(bufferOut, 0, bytes);
}
in.close();
// 结尾部分
byte[] foot = ("rn--" + BOUNDARY + "--rn").getBytes("utf-8");// 定义最后数据分隔线
out.write(foot);
out.flush();
out.close();
StringBuffer buffer = new StringBuffer();
BufferedReader reader = null;
String result = null;
try
{
// 定义BufferedReader输入流来读取URL的响应
reader = new BufferedReader(new InputStreamReader(con.getInputStream()));
String line = null;
while ((line = reader.readLine()) != null)
{
buffer.append(line);
}
if (result == null)
{
result = buffer.toString();
}
} catch (IOException e)
{
e.printStackTrace();
} finally
{
if (reader != null)
{
reader.close();
}
}
return result;
}