jdk1.5获取子网广播地址
用jdk1.6可以很容易的获取子网广播地址，但是1.5并没有实现相应的方法。我写了如下代码，已经在window xp和linux redhat中测试通过。第一个类：实现子网广播地址
import java.io.BufferedReader;import java.io.DataInputStream;import java.io.InputStreamReader;import java.net.InetAddress;import java.net.NetworkInterface;import java.net.SocketException;import java.net.UnknownHostException;import java.util.Enumeration;import java.util.Vector;public class SubnetAddress{ private static Process p; public void SubnetAddress(){ } /** * 获取本机IP * @return */ private String getIpAddressFromLinux(){ Enumeration netInterfaces; String result=null; try { netInterfaces = NetworkInterface.getNetworkInterfaces(); InetAddress ip = null; while(netInterfaces.hasMoreElements()){ NetworkInterface ni=(NetworkInterface)netInterfaces.nextElement(); ip=(InetAddress) ni.getInetAddresses().nextElement(); if( !ip.isLoopbackAddress()&& ip.getHostAddress().indexOf(":")==-1) { result=ip.getHostAddress(); break; } else ip=null; } } catch (SocketException e) { e.printStackTrace(); } return result; } /** * 获取本机IP * @return */ private String getIpAddress(){ String result=null; InetAddress inet; try { inet = InetAddress.getLocalHost(); result = inet.getHostAddress(); } catch (UnknownHostException e) { e.printStackTrace(); } return result; } /** * 使用ipconfig/all命令 * 获取windows系统上的子网掩码 * @return */ private String getSubnetAddressForWindow(){ String cmd = "cmd.exe /c ipconfig/all"; //window下获取子网掩码的命令 String find ="Subnet Mask";//子网掩码的提示 Vector ipConfigs; ipConfigs = execute(cmd); Object[] ipConfigArray=ipConfigs.toArray(); String result = null; for(int i=0;i<ipConfigArray.length;i++){ String ipConfig = ipConfigArray.toString(); if(!ipConfig.equalsIgnoreCase("") && ipConfig.indexOf(find)!=-1){ String[] subnet = ipConfig.split(":"); result = subnet.substring(1); break; } } return result; } /** * 使用ifconfig命令 * 获取linux系统上的子网掩码 * @return */ private String getSubnetAddressForLinux(){ String cmd = "ifconfig"; //linux下获取子网掩码的命令 String find = "Mask";//子网掩码的提示 Vector ipConfigs; ipConfigs = execute(cmd); Object[] ipConfigArray=ipConfigs.toArray(); String result = null; for(int i=0;i<ipConfigArray.length;i++){ String ipConfig = ipConfigArray.toString(); if(!ipConfig.equalsIgnoreCase("") && ipConfig.indexOf(find)!=-1){ String[] subnet1 = ipConfig.split(find); String[] subnet = subnet1.split(":"); result = subnet; break; } } return result; } /** * 执行命令 * @param shellCommand * @return */ private Vector execute(String shellCommand){ try{ Start(shellCommand); Vector vResult=new Vector(); DataInputStream in=new DataInputStream(p.getInputStream()); BufferedReader reader=new BufferedReader(new InputStreamReader(in)); String line; do{ line=reader.readLine(); if(line==null){ break; } else{ vResult.addElement(line); } }while(true); reader.close(); return vResult; }catch(Exception e){ return null; } } private void Start(String shellCommand){ try{ if(p!=null){ p.destroy(); p=null; } Runtime sys=Runtime.getRuntime(); p=sys.exec(shellCommand); }catch(Exception e){ e.printStackTrace(); } } /** * 根据本机IP和子网掩码，计算子网广播地址 * @param ip 本机ip * @param subnet 本机子网掩码 * @return */ public String calculate() { String os = System.getProperty("os.name").substring(0, 3); String subnet; if(os.equalsIgnoreCase("win")){ subnet = getSubnetAddressForWindow(); } else{ subnet = getSubnetAddressForLinux(); } String ip = getIpAddress(); String[] ips = ip.split("\\."); String[] subnets = subnet.split("\\."); StringBuffer sb = new StringBuffer(); for(int i = 0; i < ips.length; i++) { ips = String.valueOf((~Integer.parseInt(subnets))|(Integer.parseInt(ips))); sb.append(turnToStr(Integer.parseInt(ips))); if(i != (ips.length-1)) sb.append("."); } return turnToIp(sb.toString()); } /** * 把带符号整形转换为二进制 * @param num * @return */ private String turnToStr(int num) { String str = ""; str = Integer.toBinaryString(num); int len = 8 - str.length(); // 如果二进制数据少于8位,在前面补零. for (int i = 0; i < len; i++) { str = "0" + str; } //如果num为负数，转为二进制的结果有32位，如1111 1111 1111 1111 1111 1111 1101 1110 //则只取最后的8位. if (len < 0) str = str.substring(24, 32); return str; } /** * 把二进制形式的ip，转换为十进制形式的ip * @param str * @return */ private String turnToIp(String str){ String[] ips = str.split("\\."); StringBuffer sb = new StringBuffer(); for (int i = 0; i < ips.length; i++) { sb.append(turnToInt(ips)); sb.append("."); } sb.deleteCharAt(sb.length() - 1); return sb.toString(); } /** * 把二进制转换为十进制 * @param str * @return */ private int turnToInt(String str){ int total = 0; int top = str.length(); for (int i = 0; i < str.length(); i++) { String h = String.valueOf(str.charAt(i)); top--; total += ((int) Math.pow(2, top)) * (Integer.parseInt(h)); } return total; }}
第二个类：调用上个类中的方法
import java.net.SocketException;import java.net.UnknownHostException;public class test{ public static void main(String[] args) throws SocketException, UnknownHostException{ System.out.println(System.getProperty("os.name")); SubnetAddress sa = new SubnetAddress(); String s = sa.calculate(); System.out.println(s); }}
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