java获取外网ip地址

转自：http://blog.163.com/houjunchang_daxue/blog/static/13037938320134543310451/
/**
* 获取外网IP、归属地、操作系统
* @return
*/
public static String[] getIp(){
String[] obj = new String[3];
StringBuffer strForeignIP = new StringBuffer("");
StringBuffer strLocation = new StringBuffer("");
StringBuffer strOperatorMessageation = new StringBuffer("");
String ipAddress = "";
String ipLocation = "";
String ipSystem = "";
StringBuffer strUrl =new StringBuffer("http://www.cz88.net/ip/viewip778.aspx");
try{
URL url = new URL(strUrl.toString());
URLConnection context = url.openConnection();
InputStream in = context.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(in, "gb2312"));//防止读出来的是乱码

String s = "";
StringBuffer sb = new StringBuffer("");
while ((s = br.readLine()) != null) {
sb.append(s + "\r\n");
}
br.close();
String webContent = sb.toString();
if (null!=webContent && webContent.trim().length()>0){
String flagofForeignIPString = "IPMessage";
int startIP = webContent.indexOf(flagofForeignIPString) + flagofForeignIPString.length() + 2;
int endIP = webContent.indexOf("</span>", startIP);
strForeignIP.delete(0, webContent.length());
strForeignIP.append(webContent.substring(startIP, endIP));

String flagofLocationString = "AddrMessage";
int startLoc = webContent.indexOf(flagofLocationString)+ flagofLocationString.length() + 2;
int endLoc = webContent.indexOf("</span>", startLoc);
strLocation.delete(0, webContent.length());
strLocation.append(webContent.substring(startLoc, endLoc));

String flagoOperatorMessage = "OperatorMessage";
int startOpera = webContent.indexOf(flagoOperatorMessage)+ flagoOperatorMessage.length() + 2;
int endOpera = webContent.indexOf("</span>", startOpera);
strOperatorMessageation.delete(0, webContent.length());
strOperatorMessageation.append(webContent.substring(startOpera, endOpera));
}
}catch(Exception e){
System.out.println("IpUtil:get ip is failed:"+e.getMessage());
e.printStackTrace();
}
if(strForeignIP.toString().trim().length()<0){
ipAddress = "未知";
}else{
ipAddress = strForeignIP.toString();
}

if(strForeignIP.toString().trim().length()<0){
ipLocation = "未知";
}else{
ipLocation = strLocation.toString();
}

if(strForeignIP.toString().trim().length()<0){
ipSystem = "未知";
}else{
ipSystem = strOperatorMessageation.toString();
}
obj[0]=ipAddress;
obj[1]=ipLocation;
obj[2]=ipSystem;
return obj;
}