Ⅰ java查找本機ip地址
注意第九行：InetAddress host_address = ....; 這說明host_address 本身是一個InetAddress類型的對象而不是String類型，所以要用toString（）轉換成String類型才能被String類型的str接收。這是嚴格意義上按照規范來講。但如果你不用toString的話應該也可以，會默認把它轉成String類型的。
Ⅱ java中如何獲取到本機的外網ip地址
java獲取本機的外網ip示例：
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* 獲取本機外網IP地址
* 思想是訪問網站http://checkip.dyndns.org/，得到返回的文本後解析出本機在外網的IP地址
* @author pieryon
*
*/
public class ExternalIpAddressFetcher {
// 外網IP提供者的網址
private String externalIpProviderUrl;
// 本機外網IP地址
private String myExternalIpAddress;
public ExternalIpAddressFetcher(String externalIpProviderUrl) {
this.externalIpProviderUrl = externalIpProviderUrl;
String returnedhtml = fetchExternalIpProviderHTML(externalIpProviderUrl);
parse(returnedhtml);
}
/**
* 從外網提供者處獲得包含本機外網地址的字元串
* 從http://checkip.dyndns.org返回的字元串如下
* <html><head><title>Current IP Check</title></head><body>Current IP Address: 123.147.226.222</body></html>
* @param externalIpProviderUrl
* @return
*/
private String fetchExternalIpProviderHTML(String externalIpProviderUrl) {
// 輸入流
InputStream in = null;
// 到外網提供者的Http連接
HttpURLConnection httpConn = null;
try {
// 打開連接
URL url = new URL(externalIpProviderUrl);
httpConn = (HttpURLConnection) url.openConnection();
// 連接設置
HttpURLConnection.setFollowRedirects(true);
httpConn.setRequestMethod("GET");
httpConn.setRequestProperty("User-Agent",
"Mozilla/4.0 (compatible; MSIE 6.0; Windows 2000)");
// 獲取連接的輸入流
in = httpConn.getInputStream();
byte[] bytes=new byte[1024];// 此大小可根據實際情況調整
// 讀取到數組中
int offset = 0;
int numRead = 0;
while (offset < bytes.length
&& (numRead=in.read(bytes, offset, bytes.length-offset)) >= 0) {
offset += numRead;
}
// 將位元組轉化為為UTF-8的字元串
String receivedString=new String(bytes,"UTF-8");
// 返回
return receivedString;
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
in.close();
httpConn.disconnect();
} catch (Exception ex) {
ex.printStackTrace();
}
}
// 出現異常則返回空
return null;
}
/**
* 使用正則表達式解析返回的HTML文本,得到本機外網地址
* @param html
*/
private void parse(String html){
Pattern pattern=Pattern.compile("(\\d{1,3})[.](\\d{1,3})[.](\\d{1,3})[.](\\d{1,3})", Pattern.CASE_INSENSITIVE);
Matcher matcher=pattern.matcher(html);
while(matcher.find()){
myExternalIpAddress=matcher.group(0);
}
}
/**
* 得到本機外網地址,得不到則為空
* @return
*/
public String getMyExternalIpAddress() {
return myExternalIpAddress;
}
public static void main(String[] args){
ExternalIpAddressFetcher fetcher=new ExternalIpAddressFetcher("http://checkip.dyndns.org/");
System.out.println(fetcher.getMyExternalIpAddress());
}
}
Ⅲ java中獲取本地IP地址
方法如下：
方法一，使用CMD命令：
public static String getLocalIPForCMD(){
StringBuilder sb = new StringBuilder();
String command = "cmd.exe /c ipconfig | findstr IPv4";
try {
Process p = Runtime.getRuntime().exec(command);
BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));
String line = null;
while((line = br.readLine()) != null){
line = line.substring(line.lastIndexOf(":")+2,line.length());
sb.append(line);
}
br.close();
p.destroy();
} catch (IOException e) {
e.printStackTrace();
}
return sb.toString();
}
方法二，使用Java方法：
public static String getLocalIPForJava(){
StringBuilder sb = new StringBuilder();
try {
Enumeration<NetworkInterface> en = NetworkInterface.getNetworkInterfaces();
while (en.hasMoreElements()) {
NetworkInterface intf = (NetworkInterface) en.nextElement();
Enumeration<InetAddress> enumIpAddr = intf.getInetAddresses();
while (enumIpAddr.hasMoreElements()) {
InetAddress inetAddress = (InetAddress) enumIpAddr.nextElement();
if (!inetAddress.isLoopbackAddress() && !inetAddress.isLinkLocalAddress()
&& inetAddress.isSiteLocalAddress()) {
sb.append(inetAddress.getHostAddress().toString()+"\n");
}
}
}
} catch (SocketException e) { }
return sb.toString();
}
Ⅳ java獲得IP地址
簡單實現代碼如下：
js獲取來源頁地址方法：
var url = document.referrer;
document.write（url）；
jsp獲取來源頁地址方法：
String url = request.getHeader（」Referer」）；
System.out.println（url）；
對比兩個方法：
1.js里是」referrer」，jsp里是」referer」，前者比後者多一個」r」；
2.前者如直接輸入網址，則顯示為空，後者顯示null;
import java.net.*;
public class ip5 {
public static void main(String args[]) throws Exception {
String ip = InetAddress.getLocalHost().getHostAddress();
System.out.println(ip);
}
}