Java 中的 Java.net.Authenticator 类
原文:https://www . geesforgeks . org/Java-net-authenticator-class-Java/
认证器类用于需要认证才能访问某个网址的情况。一旦知道需要进行身份验证，它就会提示用户输入相同的内容，或者使用一些硬编码的用户名和密码。 要使用该类，请遵循以下步骤-
- 创建一个扩展验证器的类。让我们将其命名为 customAuth。
- 重写 getPasswordAuthentication()方法。此方法包含获取请求身份验证的实体的详细信息的几种方法。所有这些方法将在后面详细讨论。
-
Set the newly created subclass as the default authenticator to be used when a http server asks for authentcation, with setDefault(Authenticator a) method of Authenticator class.
方法:
-
设置默认值(认证者 a) : 设置当 HTTP 服务器需要认证时使用的认证者。
```java Syntax : public static void setDefault(Authenticator a) throws SecurityException Parameter : a : authenticator to be set as default Throws : SecurityException : if security manager doesn't allow setting default authenticator
```
-
requestPasswordAuthentication() : Asks the authenticator registered with the system for password. Returns username/password or null if not found.
```java Syntax : public static PasswordAuthentication requestPasswordAuthentication( InetAddress addr, int port, String protocol, String prompt, String scheme) Parameter : addr : Inet address of the site asking for authentication port : port of requesting site protocol : protocol used for connection prompt : message for the user scheme : authentication scheme Throws : SecurityException : if security manager doesn't allow setting password authentication.
```
另一种重载方法，可以在 inetaddress 不可用时使用主机名的情况下使用。
```java Syntax : public static PasswordAuthentication requestPasswordAuthentication( String host, InetAddress addr, int port, String protocol, String prompt, String scheme) Parameter : host : hostname of the site asking for authentication addr : Inet address of the site asking for authentication port : port of requesting site protocol : protocol used for connection prompt : message for the user scheme : authentication scheme Throws : SecurityException : if security manager doesn't allow setting password authentication.
```
另一种重载方法，如果请求身份验证的站点的 URL 是已知的，而不是地址和主机名，则可以使用这种方法。
```java Syntax : public static PasswordAuthentication requestPasswordAuthentication( String host, InetAddress addr, int port, String protocol, String prompt, URL url, String scheme) Parameter : host : hostname of the site asking for authentication addr : Inet address of the site asking for authentication port : port of requesting site protocol : protocol used for connection prompt : message for the user url : URL of the site requesting authentication scheme : authentication scheme Throws : SecurityException : if security manager doesn't allow setting password authentication.
```
-
getRequestingHost() :返回请求身份验证的站点的主机名。
```java Syntax : protected final String getRequestingHost()
```
-
getRequestingSite() :返回请求认证的站点的地址。
```java Syntax : protected final InetAddress getRequestingSite()
```
-
getRequestingPort() :返回连接的端口。
```java Syntax : protected final int getRequestingPort()
```
-
getRequestingProtocol() :返回请求连接的协议。
```java Syntax : protected final String getRequestingProtocol()
```
-
getrequestingrompt():返回请求者提示的消息。
```java Syntax : protected final String getRequestingPrompt()
```
-
getRequestingScheme() :返回请求站点的方案。
```java Syntax : protected final String getRequestingScheme()
```
-
getpassword authentication():需要密码验证时调用此方法。所有子类都必须重写此方法，因为默认方法总是返回 null。
```java Syntax : protected PasswordAuthentication getPasswordAuthentication()
```
-
getRequestingURL() :返回请求者的 URL。
```java Syntax : protected final URL getRequestingURL()
```
-
getRequestorType() :如果请求者是代理或者服务器，返回。
```java Syntax : protected Authenticator.RequestorType getRequestorType()
```
Java 实现:
```java import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.net.Authenticator; import java.net.InetAddress; import java.net.MalformedURLException; import java.net.PasswordAuthentication; import java.net.URL;
public class javanetauthenticator { public static void main(String[] args) {
try {
// setDefault() method // Sets the authenticator that will be used by the networking code // when a proxy or an HTTP server asks for authentication. Authenticator.setDefault(new CustomAuthenticator());
URL url = new URL("http://securedwebsite.co.in/index.htm");
// read text returned by server BufferedReader in = new BufferedReader(new InputStreamReader(url.openStream()));
String line; while ((line = in.readLine()) != null) { System.out.println(line); } in.close();
} catch (MalformedURLException e) { System.out.println("Malformed URL: " + e.getMessage()); } catch (IOException e) { System.out.println("I/O Error: " + e.getMessage()); }
}
public static class CustomAuthenticator extends Authenticator {
// getPasswordAuthentication() method // Called when password authorization is needed protected PasswordAuthentication getPasswordAuthentication() {
// requestPasswordAuthentication() method // uncomment this if default authenticator is registered with // the system // PasswordAuthentication pa=requestPasswordAuthentication // (inetaddr, port, protocol, prompt, scheme);
// getRequestingPrompt() method String prompt = getRequestingPrompt();
// getRequestingHost() method String hostname = getRequestingHost();
// getRequestingSite() method InetAddress ipaddr = getRequestingSite();
// getRequestingPort() method int port = getRequestingPort();
// getRequestingProtocol() method String protocol = getRequestingProtocol();
// getRequestingScheme() method String scheme = getRequestingScheme();
// getRequestingURL() method URL u = getRequestingURL();
// getRequestorType() method RequestorType rtype = getRequestorType();
System.out.println("prompt:" + prompt); System.out.println("hostname:" + hostname); System.out.println("ipaddress:" + ipaddr); System.out.println("port:" + port); System.out.println("protocolo:" + protocol); System.out.println("scheme:" + scheme); System.out.println("URL:" + u); System.out.println("Requester Type:" + rtype);
// hardcoded username and password to be used // this part can be replaced by an interactive code // to take uid and pwd form user String username = "admin"; String password = "admin1";
// Return the information (a data holder that is used by // Authenticator) return new PasswordAuthentication(username, password.toCharArray());
}
} } ```
注意:这个程序只是为了解释 Authenticator 类程序的流程。程序中使用的网址是随机选择的，不代表任何实际的网址。这个程序只是展示了如何使用 Authenticator 类的方法。通过将网址更改为需要验证才能进入的服务器来测试该程序。
参考: 官方 Java 文档
本文由里沙布·马赫塞供稿。如果你喜欢 GeeksforGeeks 并想投稿，你也可以使用contribute.geeksforgeeks.org写一篇文章或者把你的文章邮寄到 contribute@geeksforgeeks.org。看到你的文章出现在极客博客主页上，帮助其他极客。
如果你发现任何不正确的地方，或者你想分享更多关于上面讨论的话题的信息，请写评论。
-
版权属于：月萌API www.moonapi.com，转载请注明出处
