cookie 的作用，就是当一个浏览器通过http 请求访问一个服务器时，这个服务器会返回key/value 键值对给客户端浏览器，在servlet 中可以这样增加cookie ，tomcat的 版本是7
public void addcookies(HttpServletResponse response,String key,String value){
Cookie cookie = new Cookie(key,value);
response.addCookie(cookie);
}
生成cookie 对象，将对象增加到httpServletResponse 对象中，用于返回到客户端，在tomcat 服务器中，其实就是调用response 的门面方法。org.apache.catalina.connector.ResponseFacade 的addCookie 方法
@Override
public void addCookie(Cookie cookie) {
//判断response 是否提交
if (isCommitted()) {
return;
}
response.addCookie(cookie);
}
将cookie 对象委托给被装饰的org.apache.catalina.connector.Response 类处理，ResponseFacade 是Responese 类的一个门面类，
public void addCookie(final Cookie cookie) {
if (included || isCommitted()) {
return;
}
// 生成符合http 协议 cookie 格式的字符串
final StringBuffer sb = generateCookieString(cookie);
//将字符串放到响应头中
addHeader("Set-Cookie", sb.toString());
}
具体的生成方式
扫描二维码关注公众号，回复：
301005 查看本文章
public StringBuffer generateCookieString(final Cookie cookie) {
final StringBuffer sb = new StringBuffer();
//web application code can receive a IllegalArgumentException
//from the appendCookieValue invocation
if (SecurityUtil.isPackageProtectionEnabled()) {
AccessController.doPrivileged(new PrivilegedAction<Void>() {
@Override
public Void run(){
ServerCookie.appendCookieValue
(sb, cookie.getVersion(), cookie.getName(),
cookie.getValue(), cookie.getPath(),
cookie.getDomain(), cookie.getComment(),
cookie.getMaxAge(), cookie.getSecure(),
cookie.isHttpOnly());
return null;
}
});
} else {
ServerCookie.appendCookieValue
(sb, cookie.getVersion(), cookie.getName(), cookie.getValue(),
cookie.getPath(), cookie.getDomain(), cookie.getComment(),
cookie.getMaxAge(), cookie.getSecure(),
cookie.isHttpOnly());
}
return sb;
}
org.apache.tomcat.util.http.ServerCookie 类是处理生成cookie 的一个实体类,继承 Serializable 接口，可以序列化在网络上传输具体生成cookie 的处理逻辑
public static void appendCookieValue( StringBuffer headerBuf,
int version,
String name,
String value,
String path,
String domain,
String comment,
int maxAge,
boolean isSecure,
boolean isHttpOnly)
{
StringBuffer buf = new StringBuffer();
// Servlet implementation checks name
buf.append( name );
buf.append("=");
// Servlet implementation does not check anything else
/*
* The spec allows some latitude on when to send the version attribute
* with a Set-Cookie header. To be nice to clients, we'll make sure the
* version attribute is first. That means checking the various things
* that can cause us to switch to a v1 cookie first.
*
* Note that by checking for tokens we will also throw an exception if a
* control character is encountered.
*/
// Start by using the version we were asked for
int newVersion = version;
// If it is v0, check if we need to switch
if (newVersion == 0 &&
(!CookieSupport.ALLOW_HTTP_SEPARATORS_IN_V0 &&
CookieSupport.isHttpToken(value) ||
CookieSupport.ALLOW_HTTP_SEPARATORS_IN_V0 &&
CookieSupport.isV0Token(value))) {
// HTTP token in value - need to use v1
newVersion = 1;
}
if (newVersion == 0 && comment != null) {
// Using a comment makes it a v1 cookie
newVersion = 1;
}
if (newVersion == 0 &&
(!CookieSupport.ALLOW_HTTP_SEPARATORS_IN_V0 &&
CookieSupport.isHttpToken(path) ||
CookieSupport.ALLOW_HTTP_SEPARATORS_IN_V0 &&
CookieSupport.isV0Token(path))) {
// HTTP token in path - need to use v1
newVersion = 1;
}
if (newVersion == 0 &&
(!CookieSupport.ALLOW_HTTP_SEPARATORS_IN_V0 &&
CookieSupport.isHttpToken(domain) ||
CookieSupport.ALLOW_HTTP_SEPARATORS_IN_V0 &&
CookieSupport.isV0Token(domain))) {
// HTTP token in domain - need to use v1
newVersion = 1;
}
// Now build the cookie header
// Value
maybeQuote(buf, value);
// Add version 1 specific information
if (newVersion == 1) {
// Version=1 ... required
buf.append ("; Version=1");
// Comment=comment
if ( comment!=null ) {
buf.append ("; Comment=");
maybeQuote(buf, comment);
}
}
// Add domain information, if present
if (domain!=null) {
buf.append("; Domain=");
maybeQuote(buf, domain);
}
// Max-Age=secs ... or use old "Expires" format
if (maxAge >= 0) {
if (newVersion > 0) {
buf.append ("; Max-Age=");
buf.append (maxAge);
}
// IE6, IE7 and possibly other browsers don't understand Max-Age.
// They do understand Expires, even with V1 cookies!
if (newVersion == 0 || CookieSupport.ALWAYS_ADD_EXPIRES) {
// Wdy, DD-Mon-YY HH:MM:SS GMT ( Expires Netscape format )
buf.append ("; Expires=");
// To expire immediately we need to set the time in past
if (maxAge == 0) {
buf.append( ancientDate );
} else {
OLD_COOKIE_FORMAT.get().format(
new Date(System.currentTimeMillis() +
maxAge*1000L),
buf, new FieldPosition(0));
}
}
}
// Path=path
if (path!=null) {
buf.append ("; Path=");
maybeQuote(buf, path);
}
// Secure
if (isSecure) {
buf.append ("; Secure");
}
// HttpOnly
if (isHttpOnly) {
buf.append("; HttpOnly");
}
headerBuf.append(buf);
}
tomcat 最终构造响应头的方法在org.apache.coyote.http11.AbstractHttp11Processor 的prepareResponse中，具体片段
int size = headers.size();
for (int i = 0; i < size; i++) {
getOutputBuffer().sendHeader(headers.getName(i), headers.getValue(i));
}