commonutil.java

很简单的几个类

package cn.onlinema.util;

public class CommonUtil {

	
	/**
	 * 读取输入流中的字节
	 * @param in = java.io.InputStream
	 * @return byte[] 读取到的所有字节
	 * @throws java.io.IOException
	 */
	public static byte[] readInputStream(java.io.InputStream in) throws java.io.IOException{
		int len = 10240;
		byte[] total = new byte[len];
		int length = in.read(total,0,len);//如果没有读取到字节返回-1,读取到则返回读取到的字节长度
		if(length == -1) {//如果没有读取到字节,则返回空
			return new byte[0];
		} else if(length < len) {//如果读取到的字节不足字节数组空间,则截取多余部分
			byte[] t = (byte[])total.clone();
			total = new byte[length];
			for(int i=0; i<total.length; i++) {
				total[i] = t[i];
			}
		}
		while(length == len){//如果读取到的字节长度等于字节空间长度,则意味着很可能还有字节没有读出
			//读取剩余字节
			byte[] temp = new byte[len];
			length = in.read(temp,0,len);
			//重组字节数组
			byte[] t = (byte[])total.clone();
			total = new byte[t.length+length];
			for(int i=0; i<t.length; i++){
				total[i]=t[i];
			}
			for(int i=0; i<length; i++){
				total[t.length+i]=temp[i];
			}
			//重组字节数组完毕
		}
		return total;
	}
	
	/**
	 * 该方法返回以格式format为标准的当前时间
	 * @param format - y(年) M(月) d(日) H(24制时) h(12制时) m(分) s(秒) eg.yyyy-MM-dd HH:mm:ss
	 * @return 返回时间字符串
	 */
	public static String getTime(String format) {
		return new java.text.SimpleDateFormat(format).format(new java.util.Date());
	}
	
	public static String readFromStdin() throws java.io.IOException{
		java.io.BufferedReader br = new java.io.BufferedReader(new java.io.InputStreamReader(System.in));
		return br.readLine();
	}
	
	public static java.net.ServerSocket simpleSocketServer(String host, int port) throws java.io.IOException {
		java.net.ServerSocket server = new java.net.ServerSocket();
		server.bind(new java.net.InetSocketAddress(host, port));
//		java.net.Socket socket = server.accept();
//		java.io.InputStream in = socket.getInputStream();
//		java.io.OutputStream out = socket.getOutputStream();
		return server;
	}
	
	public static java.nio.channels.SocketChannel simpleSocketClient(String host, int port) throws java.io.IOException {
		java.nio.channels.SocketChannel sc = java.nio.channels.SocketChannel.open();
		sc.connect(new java.net.InetSocketAddress(host, port));
//		java.nio.ByteBuffer buffer = java.nio.ByteBuffer.allocate("".getBytes().length);
		return sc;
	}
}