基于JAAS实现登录

本例是认证的实现，JAAS定义了可插拔的认证机制，使认证逻辑独立开来，可通过修改配置文件切换认证模块。

官方参考：
http://java.sun.com/products/archive/jaas/ http://java.sun.com/j2se/1.4.2/docs/guide/security/jaas/JAASRefGuide.html
security.pdf

一、配置文件及设置

1. 配置文件（假设为D:/jaas.conf）：



Sample{



com.fastunit.samples.jaas.SampleLoginModule required debug
=
false
;



}
;

此文件定义了一个“Sample”验证模块，使用SampleLoginModule来进行验证。

2. 启用配置文件：

-Djava.security.auth.login.config=D:/jaas.conf

二、客户端调用

import
javax.security.auth.login.LoginContext;

import
javax.security.auth.login.LoginException;

import
javax.servlet.http.HttpServletRequest;

public

class
LoginManager {


public

static

boolean
login(HttpServletRequest request) {


try
{

String username
=
request.getParameter(
"
username
"
);

String password
=
request.getParameter(
"
password
"
);


//
此处指定了使用配置文件的“Sample”验证模块，对应的实现类为SampleLoginModule

LoginContext lc
=

new
LoginContext(
"
Sample
"
,
new
SampleCallbackHandler(

username, password));

lc.login();
//
如果验证失败会抛出异常


return

true
;

}
catch
(LoginException e) {

e.printStackTrace();


return

false
;

}
catch
(SecurityException e) {

e.printStackTrace();


return

false
;

}

}

}



import
java.io.IOException;

import
javax.security.auth.callback.Callback;

import
javax.security.auth.callback.CallbackHandler;

import
javax.security.auth.callback.NameCallback;

import
javax.security.auth.callback.PasswordCallback;

import
javax.security.auth.callback.UnsupportedCallbackException;

public

class
SampleCallbackHandler
implements
CallbackHandler {


private
String username;


private
String password;


public
SampleCallbackHandler(
final
String username,
final
String password) {


this
.username
=
username;


this
.password
=
password;

}


public

void
handle(Callback[] callbacks)
throws
IOException,

UnsupportedCallbackException {


for
(
int
index
=

0
; index
<
callbacks.length; index
++
) {


if
(callbacks[index]
instanceof
NameCallback) {

NameCallback ncb
=
(NameCallback) callbacks[index];

ncb.setName(username);

}


if
(callbacks[index]
instanceof
PasswordCallback) {

PasswordCallback pcb
=
(PasswordCallback) callbacks[index];

pcb.setPassword(password.toCharArray());

}

}

}

}

三、验证实现

import
java.io.IOException;

import
java.util.Map;

import
javax.security.auth.Subject;

import
javax.security.auth.callback.Callback;

import
javax.security.auth.callback.CallbackHandler;

import
javax.security.auth.callback.NameCallback;

import
javax.security.auth.callback.PasswordCallback;

import
javax.security.auth.callback.UnsupportedCallbackException;

import
javax.security.auth.login.LoginException;

import
javax.security.auth.spi.LoginModule;

public

class
SampleLoginModule
implements
LoginModule {


private

boolean
isAuthenticated
=

false
;


private
CallbackHandler callbackHandler;


private
Subject subject;


private
SamplePrincipal principal;


public

void
initialize(Subject subject, CallbackHandler callbackHandler,

Map sharedState, Map options) {


this
.subject
=
subject;


this
.callbackHandler
=
callbackHandler;

}


public

boolean
login()
throws
LoginException {


try
{

NameCallback nameCallback
=

new
NameCallback(
"
username
"
);

PasswordCallback passwordCallback
=

new
PasswordCallback(
"
password
"
,


false
);


final
Callback[] calls
=

new
Callback[] { nameCallback, passwordCallback };


//
获取用户数据

callbackHandler.handle(calls);

String username
=
nameCallback.getName();

String password
=
String.valueOf(passwordCallback.getPassword());


//
TODO 验证，如：查询数据库、LDAP。。。


if
(
true
) {
//
验证通过

principal
=

new
SamplePrincipal(username);

isAuthenticated
=

true
;

}
else
{


throw

new
LoginException(
"
user or password is wrong
"
);

}

}
catch
(IOException e) {


throw

new
LoginException(
"
no such user
"
);

}
catch
(UnsupportedCallbackException e) {


throw

new
LoginException(
"
login failure
"
);

}


return
isAuthenticated;

}


/**

* 验证后的处理,在Subject中加入用户对象


*/


public

boolean
commit()
throws
LoginException {


if
(isAuthenticated) {

subject.getPrincipals().add(principal);

}
else
{


throw

new
LoginException(
"
Authentication failure
"
);

}


return
isAuthenticated;

}


public

boolean
abort()
throws
LoginException {


return

false
;

}


public

boolean
logout()
throws
LoginException {

subject.getPrincipals().remove(principal);

principal
=

null
;


return

true
;

}

}



import
java.security.Principal;

public

final

class
SamplePrincipal
implements
Principal {


private
String name;


public
SamplePrincipal(String name) {


this
.name
=
name;

}


public
String getName() {


return
name;

}


public

boolean
equals(Object o) {


return
(o
instanceof
SamplePrincipal)


&&

this
.name.equalsIgnoreCase(((SamplePrincipal) o).name);

}


public

int
hashCode() {


return
name.toUpperCase().hashCode();

}

}