URI (uniform resource identifier)統(tǒng)一資源標志符；URL(uniform resource location )統(tǒng)一資源定位符（或統(tǒng)一資源定位器）；URI是一個相對來說更廣泛的概念，URL是URI的一種，是URI命名機制的一個子集，可以說URI是抽象的，而具體要使用URL來定位資源。URI指向的一般不是物理資源路徑，而是整個系統(tǒng)中的映射后的資源標識符。URL是Internet上用來描述信息資源的字符串，主要用在各種WWW客戶程序和服務(wù)器程序上。采用URL可以用一種統(tǒng)一的格式來描述各種信息資源，包括文件、服務(wù)器的地址和目錄等。

 URL url=new URL(http://www.apptest.com:8080/test/ios.php);

 "https", "ftp", "mailto", "telnet", "file", "ldap", "gopher", "jdbc", "rmi", "jndi", "jar", "doc", "netdoc", "nfs", "verbatim", "finger", "daytime", "systemresource"

 URL url=new URL("oschina://www.apptest.com:8080/test/ios.php");

java.net.MalformedURLException: unknown protocol

<?php$raw_post_data = file_get_contents('php://input', 'r'); 
echo "-------\$_POST------------------\n<br/>"; 
echo var_dump($_POST) . "\n";
 echo "-------php://input-------------\n<br/>"; 
echo $raw_post_data . "\n<br/>";
 $rs = json_encode($_SERVER);file_put_contents('text.html',$rs);echo '寫入成功';

public class EchoURLStreamHandlerFactory implements URLStreamHandlerFactory {
public URLStreamHandler createURLStreamHandler(String protocol){
//通過這里的分流處理不同的schema請求，當然腦殘人士認為這里才是核心代碼，URL是一套協(xié)議處理框架，如果if-else就是核心，是不是oracle要倒閉  
if(protocol.equals("echo") || protocol.equals("oschina"))   { 
   return new EchoURLStreamHandler(); //實例化協(xié)議處理Handler  
 }  
return null; }}

public class EchoURLStreamHandler extends URLStreamHandler {
@Overrideprotected URLConnection openConnection(URL u) throws IOException {
return new EchoURLConnection(u); 
//在這里我們也可以進行相應(yīng)的分流}
}

public class EchoURLConnection extends URLConnection {
private Socket connection = null;
public final static int DEFAULT_PORT = 80;public EchoURLConnection(URL url) {
super(url);}
public synchronized InputStream getInputStream() throws IOException {
if (!connected) {connect();
}
return connection.getInputStream();
}
public synchronized OutputStream getOutputStream() throws IOException {
if (!connected) {connect();
}
return connection.getOutputStream();
}
public String getContentType() {
return "text/plain";
}public synchronized void connect() throws IOException {
if (!connected) {
int port = url.getPort();
if (port < 0 || port > 65535)port = DEFAULT_PORT;
this.connection = new Socket(url.getHost(), port);
// true表示關(guān)閉Socket的緩沖,立即發(fā)送數(shù)據(jù)..其默認值為false// 
若Socket的底層實現(xiàn)不支持TCP_NODELAY選項,則會拋出SocketExceptionthis.connection.setTcpNoDelay(true);
// 表示是否允許重用Socket所綁定的本地地址this.connection.setReuseAddress(true);
// 表示接收數(shù)據(jù)時的等待超時時間,單位毫秒..其默認值為0,表示會無限等待,永遠不會超時
// 當通過Socket的輸入流讀數(shù)據(jù)時,如果還沒有數(shù)據(jù),就會等待
// 超時后會拋出SocketTimeoutException,且拋出該異常后Socket仍然是連接的,可以嘗試再次讀數(shù)據(jù)this.connection.setSoTimeout(30000);
// 表示當執(zhí)行Socket.close()時,是否立即關(guān)閉底層的Socket
// 這里設(shè)置為當Socket關(guān)閉后,底層Socket延遲5秒后再關(guān)閉,而5秒后所有未發(fā)送完的剩余數(shù)據(jù)也會被丟棄
// 默認情況下,執(zhí)行Socket.close()方法,該方法會立即返回,但底層的Socket實際上并不立即關(guān)閉
// 它會延遲一段時間,直到發(fā)送完所有剩余的數(shù)據(jù),才會真正關(guān)閉Socket,斷開連接
// Tips:當程序通過輸出流寫數(shù)據(jù)時,僅僅表示程序向網(wǎng)絡(luò)提交了一批數(shù)據(jù),由網(wǎng)絡(luò)負責(zé)輸送到接收方
// Tips:當程序關(guān)閉Socket,有可能這批數(shù)據(jù)還在網(wǎng)絡(luò)上傳輸,還未到達接收方
// Tips:這里所說的"未發(fā)送完的剩余數(shù)據(jù)"就是指這種還在網(wǎng)絡(luò)上傳輸,未被接收方接收的數(shù)據(jù)this.connection.setSoLinger(true, 5);
// 表示發(fā)送數(shù)據(jù)的緩沖區(qū)的大小this.connection.setSendBufferSize(1024);
// 表示接收數(shù)據(jù)的緩沖區(qū)的大小this.connection.setReceiveBufferSize(1024);
// 表示對于長時間處于空閑狀態(tài)(連接的兩端沒有互相傳送數(shù)據(jù))的Socket,是否要自動把它關(guān)閉,true為是
// 其默認值為false,表示TCP不會監(jiān)視連接是否有效,不活動的客戶端可能會永久存在下去,而不會注意到服務(wù)器已經(jīng)崩潰this.connection.setKeepAlive(true);
// 表示是否支持發(fā)送一個字節(jié)的TCP緊急數(shù)據(jù),socket.sendUrgentData(data)用于發(fā)送一個字節(jié)的TCP緊急數(shù)據(jù)
// 其默認為false,即接收方收到緊急數(shù)據(jù)時不作任何處理,直接將其丟棄..若用戶希望發(fā)送緊急數(shù)據(jù),則應(yīng)設(shè)其為true
// 設(shè)為true后,接收方會把收到的緊急數(shù)據(jù)與普通數(shù)據(jù)放在同樣的隊列中this.connection.setOOBInline(true);
// 該方法用于設(shè)置服務(wù)類型,以下代碼請求高可靠性和最小延遲傳輸服務(wù)(把0x04與0x10進行位或運算)
// Socket類用4個整數(shù)表示服務(wù)類型// 0x02:低成本(二進制的倒數(shù)第二位為1)
// 0x04:高可靠性(二進制的倒數(shù)第三位為1)// 0x08:最高吞吐量(二進制的倒數(shù)第四位為1)
// 0x10:最小延遲(二進制的倒數(shù)第五位為1)this.connection.setTrafficClass(0x04 | 0x10);
// 該方法用于設(shè)定連接時間,延遲,帶寬的相對重要性(該方法的三個參數(shù)表示網(wǎng)絡(luò)傳輸數(shù)據(jù)的3項指標)
// connectionTime--該參數(shù)表示用最少時間建立連接
// latency---------該參數(shù)表示最小延遲
// bandwidth-------該參數(shù)表示最高帶寬// 可以為這些參數(shù)賦予任意整數(shù)值,這些整數(shù)之間的相對大小就決定了相應(yīng)參數(shù)的相對重要性/
// 如這里設(shè)置的就是---最高帶寬最重要,其次是最小連接時間,最后是最小延遲this.connection.setPerformancePreferences(2, 1, 3);this.connected = true;StringBuilder sb = new StringBuilder();sb.append("POST " + url.getPath() + " HTTP/1.1 \r\n");
//if(url.getPort()<0 || url.getPort()>65536){sb.append("Host:").append(url.getHost()).append("\r\n");}else{sb.append("Host:").append(url.getHost()).append(":").append(url.getPort()).append("\r\n");}sb.append("Connection:keep-alive\r\n");sb.append("Date:Fri, 22 Apr 2016 13:17:35 GMT\r\n");sb.append("Vary:Accept-Encoding\r\n");sb.append("Content-Type: application/x-www-form-urlencoded,charset=utf-8\r\n");sb.append("Content-Length: ").append("name=zhangsan&password=123456".getBytes("UTF-8").length).append("\r\n");sb.append("\r\n");this.connection.getOutputStream().write(sb.toString().getBytes("UTF-8"));}}public synchronized void disconnect() throws IOException {if (connected) {this.connection.close();this.connected = false;}}}

URL.setURLStreamHandlerFactory(new EchoURLStreamHandlerFactory());
// URLConnection.setContentHandlerFactory(new EchoContentHandlerFactory());
URL url=new URL("oschina://localhost:8080/test/ios.php");
EchoURLConnection connection=(EchoURLConnection)url.openConnection();
connection.setDoOutput(true);connection.setDoInput(true); 
PrintWriter pw = new PrintWriter(new OutputStreamWriter(connection.getOutputStream()));
pw.write("name=zhangsan&password=123456");pw.flush(); 
 InputStream stream = connection.getInputStream();    
 int len = -1;  byte[] buf = new byte[256];  
while((len=stream.read(buf, 0, 256))>-1)  { 
 String line = new String(buf, 0, len);  
if(line.endsWith("\r\n0\r\n\r\n")&&len<256)   {    
     //服務(wù)器返回的是Transfer-chunked編碼,\r\n0\r\n\r\n表示讀取結(jié)束了，chunked編碼解析：http://dbscx.iteye.com/blog/830644  line = line.substring(0, line.length()-"\r\n0\r\n\r\n".length()); 
 System.out.println(line);  
break;  
}else{  System.out.println(line); 
  } 
 }  
 pw.close(); 
stream.close();

public class EchoContentHandler extends ContentHandler {
public Object getContent(URLConnection connection) throws IOException {
InputStream in = connection.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(in));
return br.readLine();
}
public Object getContent(URLConnection connection, Class[] classes) 
throws IOException {InputStream in = connection.getInputStream();
for (int i = 0; i < classes.length; i++) {
if (classes[i] == InputStream.class)return in;
else if (classes[i] == String.class)return getContent(connection);
}return null;}}

 URLConnection.setContentHandlerFactory(new EchoContentHandlerFactory());