首先，先上代码。
package pn.empire.security.filter;
import java.security.interfaces.RSAPrivateKey;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.ResourceBundle;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.lang3.StringUtils;
import org.springframework.security.authentication.AuthenticationServiceException;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.AuthenticationException;
import org.springframework.util.Assert;
import pn.empire.security.exception.CodeException;
import pn.empire.security.exception.ForbidIPException;
import pn.empire.util.NetWorkUtil;
import pn.empire.util.RSAUtils;
public class UsernamePasswordFilter
extends org.springframework.security.web.authentication.UsernamePasswordAuthenticationFilter {
// ~ Static fields/initializers
// =====================================================================================
// 用户名
public static final String SPRING_SECURITY_FORM_USERNAME_KEY = "j_username";
// 密码
public static final String SPRING_SECURITY_FORM_PASSWORD_KEY = "j_password";
public static final String SPRING_SECURITY_FORM_REDERICT_KEY = "spring-security-redirect";
private String usernameParameter = SPRING_SECURITY_FORM_USERNAME_KEY;
private String passwordParameter = SPRING_SECURITY_FORM_PASSWORD_KEY;
private boolean postOnly = true;
private String redirectParameter = SPRING_SECURITY_FORM_REDERICT_KEY;
// ~ Methods
// ========================================================================================================
public Authentication attemptAuthentication(HttpServletRequest request, HttpServletResponse response)
throws AuthenticationException {
if (postOnly && !request.getMethod().equals("POST")) {
throw new AuthenticationServiceException("Authentication method not supported: " + request.getMethod());
}
if (request == null) {
throw new AuthenticationServiceException("request is null");
}
String username = obtainUsername(request);
String password = obtainPassword(request);
String code = request.getParameter("code");
String sessionCode = (String) request.getSession(true).getAttribute("code");
request.getSession(true).removeAttribute("code");
if (sessionCode == null) {
throw new CodeException("您的验证码已过期，请刷新验证码！");
}
// 验证码相关
if (code == null) {
throw new CodeException("请输入验证码");
}
if (!code.toLowerCase().equals(sessionCode.toLowerCase())) {
throw new CodeException("请正确输入验证码！");
}
ResourceBundle resource = ResourceBundle.getBundle("forbidip");
String forbidIpsStr = resource.getString("ip.address");
List forbidIps = new ArrayList();
if (forbidIpsStr != null && forbidIpsStr.indexOf(",") != -1) {
String[] ips = forbidIpsStr.split(",");
forbidIps = Arrays.asList(ips);
}
String ip = "";
ip = NetWorkUtil.getIpAddress(request);
if (ip.indexOf("非法地址：") != -1) {
throw new ForbidIPException("非法IP");
}
if (forbidIps.size() > 0 && forbidIps.contains(ip)) {
throw new ForbidIPException("非法IP");
}
RSAPrivateKey privateKey = (RSAPrivateKey) request.getSession().getAttribute("privateKey");
try {
String str = RSAUtils.decryptByPrivateKey(password, privateKey);
password = StringUtils.reverse(str);
} catch (Exception e) {
e.printStackTrace();
}
String redirectUrl = obtainRedercitUrl(request);
if (username == null) {
username = "";
}
if (password == null) {
password = "";
}
// 自定义回调URL，若存在则放入Session
if (redirectUrl != null && !"".equals(redirectUrl)) {
request.getSession().setAttribute("callCustomRediretUrl", redirectUrl);
}
username = username.trim();
// 在这里处理密码或者用户名
UsernamePasswordAuthenticationToken authRequest = new UsernamePasswordAuthenticationToken(username, password);
// Allow subclasses to set the "details" property
setDetails(request, authRequest);
return this.getAuthenticationManager().authenticate(authRequest);
}
/**
* Enables subclasses to override the composition of the password, such as by
* including additional values and a separator.
*
* This might be used for example if a postcode/zipcode was required in addition to
* the password. A delimiter such as a pipe (|) should be used to separate the
* password and extended value(s). The AuthenticationDao will need to
* generate the expected password in a corresponding manner.
*
*
* @param request
* so that request attributes can be retrieved
*
* @return the password that will be presented in the Authentication
* request token to the AuthenticationManager
*/
protected String obtainPassword(HttpServletRequest request) {
return request.getParameter(passwordParameter);
}
/**
* Enables subclasses to override the composition of the username, such as by
* including additional values and a separator.
*
* @param request
* so that request attributes can be retrieved
*
* @return the username that will be presented in the Authentication
* request token to the AuthenticationManager
*/
protected String obtainUsername(HttpServletRequest request) {
return request.getParameter(usernameParameter);
}
/**
* Provided so that subclasses may configure what is put into the authentication
* request's details property.
*
* @param request
* that an authentication request is being created for
* @param authRequest
* the authentication request object that should have its details
* set
*/
protected void setDetails(HttpServletRequest request, UsernamePasswordAuthenticationToken authRequest) {
authRequest.setDetails(authenticationDetailsSource.buildDetails(request));
}
/**
* Sets the parameter name which will be used to obtain the username from the login
* request.
*
* @param usernameParameter
* the parameter name. Defaults to "username".
*/
public void setUsernameParameter(String usernameParameter) {
Assert.hasText(usernameParameter, "Username parameter must not be empty or null");
this.usernameParameter = usernameParameter;
}
/**
* Sets the parameter name which will be used to obtain the password from the login
* request..
*
* @param passwordParameter
* the parameter name. Defaults to "password".
*/
public void setPasswordParameter(String passwordParameter) {
Assert.hasText(passwordParameter, "Password parameter must not be empty or null");
this.passwordParameter = passwordParameter;
}
/**
* Defines whether only HTTP POST requests will be allowed by this filter. If set to
* true, and an authentication request is received which is not a POST request, an
* exception will be raised immediately and authentication will not be attempted. The
* unsuccessfulAuthentication() method will be called as if handling a failed
* authentication.
*
* Defaults to true but may be overridden by subclasses.
*/
public void setPostOnly(boolean postOnly) {
this.postOnly = postOnly;
}
protected String obtainRedercitUrl(HttpServletRequest request) {
return request.getParameter(redirectParameter);
}
}
说一下变量：
1.SPRING_SECURITY_FORM_USERNAME_KEY：这个静态常量定义了页面传递到后台中用户名的变量名。
2.SPRING_SECURITY_FORM_PASSWORD_KEY：这个静态常量定义了页面传递到后台中用户密码的变量名。
3.SPRING_SECURITY_FORM_REDERICT_KEY：这个静态常量定义了页面传递到后台中路径的变量名，因为是ajax登录，所以可以通过该变量控制登录成功后跳转至哪里。如果是表单登录，应该可以通过重定向来实现。
核心方法attemptAuthentication：
if (postOnly && !request.getMethod().equals("POST")) {
throw new AuthenticationServiceException("Authentication method not supported: " + request.getMethod());
}
上面这一段代码控制了登录请求只能以post方式进行。
String code = request.getParameter("code");
String sessionCode = (String) request.getSession(true).getAttribute("code");
request.getSession(true).removeAttribute("code");
if (sessionCode == null) {
throw new CodeException("您的验证码已过期，请刷新验证码！");
}
// 验证码相关
if (code == null) {
throw new CodeException("请输入验证码");
}
if (!code.toLowerCase().equals(sessionCode.toLowerCase())) {
throw new CodeException("请正确输入验证码！");
}
上面代码简单实现了一个验证码校验功能，在访问登录页面时，后台生成验证码并存储到session中，之后取值移除并进行校验，此处抛出了自定义异常CodeException，目的是方便失败后进行异常捕捉，明确错误信息并提示给用户。
ResourceBundle resource = ResourceBundle.getBundle("forbidip");
String forbidIpsStr = resource.getString("ip.address");
List forbidIps = new ArrayList();
if (forbidIpsStr != null && forbidIpsStr.indexOf(",") != -1) {
String[] ips = forbidIpsStr.split(",");
forbidIps = Arrays.asList(ips);
}
String ip = "";
ip = NetWorkUtil.getIpAddress(request);
if (ip.indexOf("非法地址：") != -1) {
throw new ForbidIPException("非法IP");
}
if (forbidIps.size() > 0 && forbidIps.contains(ip)) {
throw new ForbidIPException("非法IP");
}
上面代码是通过读取配置文件进行ip限制，如果是当前ip被禁止则抛出自定义异常。
当然请求的ip是从request中取得，此种获取ip的方法并不可靠，聊胜于无，如果大家有好的方法，欢迎指导。
RSAPrivateKey privateKey = (RSAPrivateKey)request.getSession().getAttribute("privateKey");
try {
String str = RSAUtils.decryptByPrivateKey(password, privateKey);
password = StringUtils.reverse(str);
} catch (Exception e) {
e.printStackTrace();
}
这一段代码是对前台传递过来的密码进行rsa解密，目前公钥私钥都是存储在session 中的，每个会话都是单独生成的，至于此种做法是否更加安全，待验证。
至于redirectUrl，此属性是为了登录成功后配合ajax可以跳转到指定路径。
setDetails(request, authRequest);
return this.getAuthenticationManager().authenticate(authRequest);
设置details，这里就是设置org.springframework.security.web.authentication.WebAuthenticationDetails实例到details中
之后会通过UserDetailServiceImpl进行校验。
以上便是UsernamePasswordFilter的主要内容了。
之后会写UserDetailServiceImpl。