javaee-cookie响应，请求小解

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1.cookie是首先由服务器向浏览器发送的

 

  cookie最早来源于服务器，它像浏览器发送的响应头，如下：

 

 

HTTP/1.1 200
Server:...
Set-Cookie: name=admin
Set-Cookie: nickname=nick_admin; 
Set-Cookie: email="[email protected]";
Set-Cookie: phone=1111111
……

 

每一个Cookie信息都用一个Set-Cookie头传送。实现如上效果的servlet代码如下：

 

 

Cookie ckName = new Cookie("name", name);
			Cookie ckNickname = new Cookie("nickname", nickname);
			ckNickname.setMaxAge(365 * 24 * 3600);
			Cookie ckEmail = new Cookie("email", "[email protected]");
			Cookie ckPhone = new Cookie("phone", "1111111");
			//奇怪，针对chrome就不生成JSESSIONID
			response.addCookie(ckName);
			response.addCookie(ckNickname);
			response.addCookie(ckEmail);
			response.addCookie(ckPhone);

 

 

 

2.浏览器返回cookie信息

 

    浏览器在收到服务器发送的cookie时，存储起来，并在每次向服务器请求时重新将cookie信息返回。如下：

 

 

POSE /** HTTP/1.1

accept : image/gif, image/jpeg, image/pjpeg, image/pjpeg, application/x-shockwave-flash, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*
accept-language : zh-cn
user-agent : Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; Trident/4.0; CIBA; .NET CLR 2.0.50727)
accept-encoding : gzip, deflate
host : localhost:8080
connection : Keep-Alive
Cookie: name=admin; nickname=nick_admin; email="[email protected]"; phone=1111111; JSESSIONID=CDF550D953DAB0E59A57D7D1CCFDDD30

 

 

 

3. http请求、发送小结

 

   通过这样一来一回，返回的cookie信息是一致的（你可以改），就可以判断唯一用户了。这种方式也可以用来实现session。

 

   读取http请求中的cookie方法如下：

 

 

String lastNickname = null;
			Cookie[] cks = request.getCookies();
			for (int i = 0; cks != null && i < cks.length; i++) {
				if ("nickname".equals(cks[i].getName())) {
					lastNickname = cks[i].getValue();
					break;
				}
			}

 

 

   或者也可以这么取

 

 

String cookieHeader = request.getHeader("Cookie");

 

 

   可以通过：http://localhost:8080/Test_servlet/ch7/CookieServlet1?name=admin&nickname=nick_admin

查看效果。

 

 

3.Cookie源代码

 

 

    Cookie类，真是难得一见的类，不是接口。

 

package javax.servlet.http;

import java.text.MessageFormat;
import java.util.ResourceBundle;

public class Cookie
  implements Cloneable
{
  private static final String LSTRING_FILE = "javax.servlet.http.LocalStrings";
  private static ResourceBundle lStrings = ResourceBundle.getBundle("javax.servlet.http.LocalStrings");
  private String name;
  private String value;
  private String comment;
  private String domain;
  private int maxAge = -1;
  private String path;
  private boolean secure;
  private int version = 0;
  private static final String tspecials = ",; ";

  public Cookie(String name, String value)
  {
    if ((!(isToken(name))) || (name.equalsIgnoreCase("Comment")) || (name.equalsIgnoreCase("Discard")) || (name.equalsIgnoreCase("Domain")) || (name.equalsIgnoreCase("Expires")) || (name.equalsIgnoreCase("Max-Age")) || (name.equalsIgnoreCase("Path")) || (name.equalsIgnoreCase("Secure")) || (name.equalsIgnoreCase("Version")) || (name.startsWith("$")))
    {
      String errMsg = lStrings.getString("err.cookie_name_is_token");
      Object[] errArgs = new Object[1];
      errArgs[0] = name;
      errMsg = MessageFormat.format(errMsg, errArgs);
      throw new IllegalArgumentException(errMsg);
    }

    this.name = name;
    this.value = value;
  }

  public void setComment(String purpose)
  {
    this.comment = purpose;
  }

  public String getComment()
  {
    return this.comment;
  }

  public void setDomain(String pattern)
  {
    this.domain = pattern.toLowerCase();
  }

  public String getDomain()
  {
    return this.domain;
  }

  public void setMaxAge(int expiry)
  {
    this.maxAge = expiry;
  }

  public int getMaxAge()
  {
    return this.maxAge;
  }

  public void setPath(String uri)
  {
    this.path = uri;
  }

  public String getPath()
  {
    return this.path;
  }

  public void setSecure(boolean flag)
  {
    this.secure = flag;
  }

  public boolean getSecure()
  {
    return this.secure;
  }

  public String getName()
  {
    return this.name;
  }

  public void setValue(String newValue)
  {
    this.value = newValue;
  }

  public String getValue()
  {
    return this.value;
  }

  public int getVersion()
  {
    return this.version;
  }

  public void setVersion(int v)
  {
    this.version = v;
  }

  private boolean isToken(String value)
  {
    int len = value.length();

    for (int i = 0; i < len; ++i) {
      char c = value.charAt(i);

      if ((c < ' ') || (c >= '') || (",; ".indexOf(c) != -1))
        return false;
    }
    return true;
  }

  public Object clone()
  {
    try
    {
      return super.clone();
    } catch (CloneNotSupportedException e) {
      throw new RuntimeException(e.getMessage());
    }
  }
}

 

参考：《深入体验Java_Web开发内幕-核心基础\》

 

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