自己动手写SSO（单点登录）

2022年 11月 4日

自己动手写SSO（单点登录）

2019独角兽企业重金招聘Python工程师标准>>>

SSO在我们的应用中非常常见，例如我们在OA系统登录了，我们就可以直接进入采购系统，不需要再登录了，这样使我们非常方便。现在网上也有很多实现方法，于是乎我也想写一个看看。我主要用到的是cookie的机制。在此，分享给大家， 同时提供源代码下载 。

进入主题：

工程说明

SSO的实现一般是会有一个SSO Server，也会叫认证中心，同时也会有被认证的系统，如OA系统、采购系统等，他们就相当于SSO Server的client。

为了更形象体现SSO，我写的SSO是有三个工程：一个SSO Server端口为8081，一个OA系统端口为8082，一个采购系统端口为8083。如图：

流程介绍

在整个SSO流程当，有两个流程非常重要，第一个是用户没有登录系统到登录系统的过程；第二是用户在一个系统当中已经登录（例如在OA系统中登录了），但又想进入另一个系统（例如进入PRO系统）的过程，如果把这两个过程搞定了，那么SSO也就搞定了。我画了两幅图来说明这两个过程。

先看用户没有登录系统到登录系统的过程，如图：

1：用户通过URL访问OA系统。

2：在OA系统中的filter发现这个URL没有ticket（你暂且就把ticket看做是门票），此时就会跳转到SSO Server。

3：SSO Server中的filter发现该客户端中的cookie中没有相应信息，也即是一个没有登录的用户，那么会跳转到登录页面。

4：用户在登录页面填写相应信息，然后通过post方式提交到SSO Server中。

5：SSO Server会校验用户信息（我为了快，我的校验方式就是要用户名为：cloud，同时密码为：cloud），同时在cookie中放username。

6：将生成ticket和username放到JVMCache中，在实际项目应该放到Memcached中，它的用处等下分析。

7，8：就是在用户访问OA系统的URL基础上加上了一个ticket参数，这样跳转到OA系统。

（此时进入OA系统时，filter发现URL是带ticket的，则filter会根据带过来的ticket并通过HttpClient的形式去调用SSO Server中的TicektServlet，这样就会返回用户名，其实这个用户名就是从JVMCache拿到的，同时马上将这个ticket从JVMCache中移除，这样保证一个ticket只会用一次，然后把返回的用户名放到session中）

9：session中有了用户名，说明用户登录成功了，则会去本应该返问的servlet。

10，11：将OA系统返回的视图给用户。

第二过程，用户已经登录成功了，但要访问另一个系统，如图：

1：用户通过URL访问PRO系统。

2：在PRO系统中的filter发现这个URL没有ticket，此时就会跳转到SSO Server。此时，由于用户登录了，所以cookie中有相应的信息（例如用户名），此时SSO Server中的filter会生成一个ticket。

3：将生成的ticket和username放到JVMCache中。

4：就是在用户访问PRO系统的URL基础上加上了一个ticket参数，这样跳转到PRO系统。

（此时进入PRO系统时，filter发现URL是带ticket的，则filter会根据带过来的ticket并通过HttpClient的形式去调用SSO Server中的TicektServlet，这样就会返回用户名，其实这个用户名就是从JVMCache拿到的，同时马上将这个ticket从JVMCache中移除，这样保证一个ticket只会用一次，然后把返回的用户名放到session中）

5：session中有了用户名，说明用户登录成功了，则会去本应该返问的servlet。

5，7：将PRO系统返回的视图给用户。

关键代码

先看SSO Server工程中的代码：

pom.xml

（注意：端口为8081）

4.0.0com.cloud.sso.serversso-serverwar0.0.1-SNAPSHOTsso-server Maven Webapphttp://maven.apache.orgjavax.servletservlet-api2.5providedsso-serverorg.mortbay.jettyjetty-maven-plugin8.1.9.v20130131stop6000/sso4808160000

SSO Server中的filter

SSOServerFilter.java


package com.cloud.sso.server.filter; import java.io.IOException; import javax.servlet.Filter; import javax.servlet.FilterChain; import javax.servlet.FilterConfig; import javax.servlet.ServletException; import javax.servlet.ServletRequest; import javax.servlet.ServletResponse; import javax.servlet.http.Cookie; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import com.cloud.sso.server.JVMCache; public class SSOServerFilter implements Filter { @Override public void destroy() {
    } @Override public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;
        String service = request.getParameter("service");
        String ticket = request.getParameter("ticket");
        Cookie[] cookies = request.getCookies();
        String username = ""; if (null != cookies) { for (Cookie cookie : cookies) { if ("sso".equals(cookie.getName())) {
                    username = cookie.getValue(); break;
                }
            }
        } if (null == service && null != ticket) {
            filterChain.doFilter(servletRequest, servletResponse); return;
        } if (null != username && !"".equals(username)) { long time = System.currentTimeMillis();
            String timeString = username + time;
            JVMCache.TICKET_AND_NAME.put(timeString, username);
            StringBuilder url = new StringBuilder();
            url.append(service); if (0 <= service.indexOf("?")) {
                url.append("&");
            } else {
                url.append("?");
            }
            url.append("ticket=").append(timeString);
            response.sendRedirect(url.toString());
        } else {
            filterChain.doFilter(servletRequest, servletResponse);
        }
    } @Override public void init(FilterConfig arg0) throws ServletException {
    }
 
}

两个servlet:

LoginServlet.java


package com.cloud.sso.server.servlet; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.Cookie; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import com.cloud.sso.server.JVMCache; public class LoginServlet extends HttpServlet { private static final long serialVersionUID = -3170191388656385924L; @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request, response);
    } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        String service = request.getParameter("service"); if ("cloud".equals(username) && "cloud".equals(password)) {
            Cookie cookie = new Cookie("sso", username);
            cookie.setPath("/");
            response.addCookie(cookie); long time = System.currentTimeMillis();
            String timeString = username + time;
            JVMCache.TICKET_AND_NAME.put(timeString, username); if (null != service) {
                StringBuilder url = new StringBuilder();
                url.append(service); if (0 <= service.indexOf("?")) {
                    url.append("&");
                } else {
                    url.append("?");
                }
                url.append("ticket=").append(timeString);
                response.sendRedirect(url.toString());
            } else {
                response.sendRedirect("/sso/index.jsp");
            }
        } else {
            response.sendRedirect("/sso/index.jsp?service=" + service);
        }
    }
 
}

TicketServlet.java


package com.cloud.sso.server.servlet; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import com.cloud.sso.server.JVMCache; public class TicketServlet extends HttpServlet { private static final long serialVersionUID = 5964206637772848290L; @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { super.doGet(request, response);
    } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String ticket = request.getParameter("ticket");
        String username = JVMCache.TICKET_AND_NAME.get(ticket);
        JVMCache.TICKET_AND_NAME.remove(ticket);
        PrintWriter writer = response.getWriter();
        writer.write(username);
    }
 
}

JVMCache.java


package com.cloud.sso.server; import java.util.HashMap; import java.util.Map; public class JVMCache { public static Map TICKET_AND_NAME = new HashMap();
}

web.xml

 index.jspssoServerFiltercom.cloud.sso.server.filter.SSOServerFilterssoServerFilter/*  logincom.cloud.sso.server.servlet.LoginServletlogin/user/loginticketcom.cloud.sso.server.servlet.TicketServletticket/ticket

下面是OA系统中的代码：

pom.xml

（注意：端口为8082）

4.0.0com.cloud.sso.oasso-oawar0.0.1-SNAPSHOTsso-oa Maven Webapphttp://maven.apache.orgjavax.servletservlet-api2.5providedcommons-httpclientcommons-httpclient3.1sso-oaorg.mortbay.jettyjetty-maven-plugin8.1.9.v20130131stop6000/oa4808260000

OA系统中的filter：

SSOClientFilter.java


package com.cloud.sso.oa.filter; import java.io.IOException; import java.net.URLEncoder; import javax.servlet.Filter; import javax.servlet.FilterChain; import javax.servlet.FilterConfig; import javax.servlet.ServletException; import javax.servlet.ServletRequest; import javax.servlet.ServletResponse; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import org.apache.commons.httpclient.HttpClient; import org.apache.commons.httpclient.methods.PostMethod; public class SSOClientFilter implements Filter { @Override public void destroy() {
    } @Override public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;
        HttpSession session = request.getSession();
        String username = (String) session.getAttribute("username");
        String ticket = request.getParameter("ticket");
        String url = URLEncoder.encode(request.getRequestURL().toString(), "UTF-8"); if (null == username) { if (null != ticket && !"".equals(ticket)) {
                PostMethod postMethod = new PostMethod("http://localhost:8081/sso/ticket");
                postMethod.addParameter("ticket", ticket);
                HttpClient httpClient = new HttpClient(); try {
                    httpClient.executeMethod(postMethod);
                    username = postMethod.getResponseBodyAsString();
                    postMethod.releaseConnection();
                } catch (Exception e) {
                    e.printStackTrace();
                } if (null != username && !"".equals(username)) {
                    session.setAttribute("username", username);
                    filterChain.doFilter(request, response);
                } else {
                    response.sendRedirect("http://localhost:8081/sso/index.jsp?service=" + url);
                }
            } else {
                response.sendRedirect("http://localhost:8081/sso/index.jsp?service=" + url);
            }
        } else {
            filterChain.doFilter(request, response);
        }
    } @Override public void init(FilterConfig arg0) throws ServletException {
    }
 
}

OAServlet.java


package com.cloud.sso.oa.servlet; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class OAServlet extends HttpServlet { private static final long serialVersionUID = 3615122544373006252L; @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.getRequestDispatcher("/WEB-INF/jsp/welcome.jsp").forward(request, response);
    } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doGet(request, response);
    }
 
    
}

web.xml

 index.jspssoClientFiltercom.cloud.sso.oa.filter.SSOClientFilterssoClientFilter/*  listcom.cloud.sso.oa.servlet.OAServletlist/list

下面是PRO系统的代码：

pom.xml

（注意：端口为8083）

4.0.0com.cloud.sso.prosso-prowar0.0.1-SNAPSHOTsso-pro Maven Webapphttp://maven.apache.orgjavax.servletservlet-api2.5providedcommons-httpclientcommons-httpclient3.1sso-proorg.mortbay.jettyjetty-maven-plugin8.1.9.v20130131stop6000/pro4808360000

PRO系统中的filter

SSOClientFilter.java


package com.cloud.sso.pro.filter; import java.io.IOException; import java.net.URLEncoder; import javax.servlet.Filter; import javax.servlet.FilterChain; import javax.servlet.FilterConfig; import javax.servlet.ServletException; import javax.servlet.ServletRequest; import javax.servlet.ServletResponse; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import org.apache.commons.httpclient.HttpClient; import org.apache.commons.httpclient.methods.PostMethod; public class SSOClientFilter implements Filter { @Override public void destroy() {
    } @Override public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;
        HttpSession session = request.getSession();
        String username = (String) session.getAttribute("username");
        String ticket = request.getParameter("ticket");
        String url = URLEncoder.encode(request.getRequestURL().toString(), "UTF-8"); if (null == username) { if (null != ticket && !"".equals(ticket)) {
                PostMethod postMethod = new PostMethod("http://localhost:8081/sso/ticket");
                postMethod.addParameter("ticket", ticket);
                HttpClient httpClient = new HttpClient(); try {
                    httpClient.executeMethod(postMethod);
                    username = postMethod.getResponseBodyAsString();
                    postMethod.releaseConnection();
                } catch (Exception e) {
                    e.printStackTrace();
                } if (null != username && !"".equals(username)) {
                    session.setAttribute("username", username);
                    filterChain.doFilter(request, response);
                } else {
                    response.sendRedirect("http://localhost:8081/sso/index.jsp?service=" + url);
                }
            } else {
                response.sendRedirect("http://localhost:8081/sso/index.jsp?service=" + url);
            }
        } else {
            filterChain.doFilter(request, response);
        }
    } @Override public void init(FilterConfig arg0) throws ServletException {
    }
 
}

ProServlet.java


package com.cloud.sso.pro.servlet; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class ProServlet extends HttpServlet { private static final long serialVersionUID = -1334093914490423930L; @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.getRequestDispatcher("/WEB-INF/jsp/welcome.jsp").forward(request, response);
    } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { super.doPost(request, response);
    }
 
}

web.xml

 index.jspssoClientFiltercom.cloud.sso.pro.filter.SSOClientFilterssoClientFilter/*  listcom.cloud.sso.pro.servlet.ProServletlist/list

运行结果：

1：分别启动这三个工程。

2：访问OA系统，URL：http://localhost:8082/oa/list

3：这样到登录页面，如图：

4：用户名为：cloud，密码为：cloud，点击登录则会显示，如图：

5：然后去进入PRO系统，URL：http://localhost:8083/pro/list，则就不需要登录了，直接进入，如图：

源码下载:http://dl.iteye.com/topics/download/50d7ecf9-a49e-3b02-8291-82a58a8c519c

转载于:https://my.oschina.net/lenglingx/blog/205269