自己动手写SSO（单点登录）

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）

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">  <modelVersion>4.0.0</modelVersion>  <groupId>com.cloud.sso.server</groupId>  <artifactId>sso-server</artifactId>  <packaging>war</packaging>  <version>0.0.1-SNAPSHOT</version>  <name>sso-server Maven Webapp</name>  <url>http://maven.apache.org</url>  <dependencies>      <dependency>          <groupId>javax.servlet</groupId>          <artifactId>servlet-api</artifactId>          <version>2.5</version>          <scope>provided</scope>      </dependency>  </dependencies>  <build>    <finalName>sso-server</finalName>    <plugins>      <plugin>          <groupId>org.mortbay.jetty</groupId>          <artifactId>jetty-maven-plugin</artifactId>          <version>8.1.9.v20130131</version>          <configuration>              <stopKey>stop</stopKey>              <stopPort>6000</stopPort>              <webAppConfig>                  <contextPath>/sso</contextPath>              </webAppConfig>              <scanIntervalSeconds>4</scanIntervalSeconds>              <connectors>                  <connector implementation="org.eclipse.jetty.server.nio.SelectChannelConnector">                      <port>8081</port>                      <maxIdleTime>60000</maxIdleTime>                  </connector>              </connectors>          </configuration>      </plugin>    </plugins>  </build></project>

 

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<String, String> TICKET_AND_NAME = new HashMap<String, String>();}

 

web.xml

<?xml version="1.0" encoding="UTF-8"?><web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:jsp="http://java.sun.com/xml/ns/javaee/jsp" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">    <welcome-file-list>        <welcome-file>index.jsp</welcome-file>    </welcome-file-list>    <filter>        <filter-name>ssoServerFilter</filter-name>        <filter-class>com.cloud.sso.server.filter.SSOServerFilter</filter-class>    </filter>    <filter-mapping>        <filter-name>ssoServerFilter</filter-name>        <url-pattern>/*</url-pattern>    </filter-mapping>    <servlet>        <servlet-name>login</servlet-name>        <servlet-class>com.cloud.sso.server.servlet.LoginServlet</servlet-class>    </servlet>    <servlet-mapping>        <servlet-name>login</servlet-name>        <url-pattern>/user/login</url-pattern>    </servlet-mapping>    <servlet>        <servlet-name>ticket</servlet-name>        <servlet-class>com.cloud.sso.server.servlet.TicketServlet</servlet-class>    </servlet>    <servlet-mapping>        <servlet-name>ticket</servlet-name>        <url-pattern>/ticket</url-pattern>    </servlet-mapping></web-app>

 

下面是OA系统中的代码：

pom.xml

（注意：端口为8082）

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">  <modelVersion>4.0.0</modelVersion>  <groupId>com.cloud.sso.oa</groupId>  <artifactId>sso-oa</artifactId>  <packaging>war</packaging>  <version>0.0.1-SNAPSHOT</version>  <name>sso-oa Maven Webapp</name>  <url>http://maven.apache.org</url>  <dependencies>      <dependency>          <groupId>javax.servlet</groupId>          <artifactId>servlet-api</artifactId>          <version>2.5</version>          <scope>provided</scope>      </dependency>      <dependency>          <groupId>commons-httpclient</groupId>          <artifactId>commons-httpclient</artifactId>          <version>3.1</version>       </dependency>  </dependencies>  <build>    <finalName>sso-oa</finalName>    <plugins>      <plugin>          <groupId>org.mortbay.jetty</groupId>          <artifactId>jetty-maven-plugin</artifactId>          <version>8.1.9.v20130131</version>          <configuration>              <stopKey>stop</stopKey>              <stopPort>6000</stopPort>              <webAppConfig>                  <contextPath>/oa</contextPath>              </webAppConfig>              <scanIntervalSeconds>4</scanIntervalSeconds>              <connectors>                  <connector implementation="org.eclipse.jetty.server.nio.SelectChannelConnector">                      <port>8082</port>                      <maxIdleTime>60000</maxIdleTime>                  </connector>              </connectors>          </configuration>      </plugin>    </plugins>  </build></project>

 

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

<?xml version="1.0" encoding="UTF-8"?><web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:jsp="http://java.sun.com/xml/ns/javaee/jsp" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">    <welcome-file-list>        <welcome-file>index.jsp</welcome-file>    </welcome-file-list>    <filter>        <filter-name>ssoClientFilter</filter-name>        <filter-class>com.cloud.sso.oa.filter.SSOClientFilter</filter-class>    </filter>    <filter-mapping>        <filter-name>ssoClientFilter</filter-name>        <url-pattern>/*</url-pattern>    </filter-mapping>    <servlet>        <servlet-name>list</servlet-name>        <servlet-class>com.cloud.sso.oa.servlet.OAServlet</servlet-class>    </servlet>    <servlet-mapping>        <servlet-name>list</servlet-name>        <url-pattern>/list</url-pattern>    </servlet-mapping></web-app>

 

 

下面是PRO系统的代码：

pom.xml

（注意：端口为8083）

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">  <modelVersion>4.0.0</modelVersion>  <groupId>com.cloud.sso.pro</groupId>  <artifactId>sso-pro</artifactId>  <packaging>war</packaging>  <version>0.0.1-SNAPSHOT</version>  <name>sso-pro Maven Webapp</name>  <url>http://maven.apache.org</url>  <dependencies>    <dependency>          <groupId>javax.servlet</groupId>          <artifactId>servlet-api</artifactId>          <version>2.5</version>          <scope>provided</scope>      </dependency>      <dependency>          <groupId>commons-httpclient</groupId>          <artifactId>commons-httpclient</artifactId>          <version>3.1</version>       </dependency>  </dependencies>  <build>    <finalName>sso-pro</finalName>    <plugins>      <plugin>          <groupId>org.mortbay.jetty</groupId>          <artifactId>jetty-maven-plugin</artifactId>          <version>8.1.9.v20130131</version>          <configuration>              <stopKey>stop</stopKey>              <stopPort>6000</stopPort>              <webAppConfig>                  <contextPath>/pro</contextPath>              </webAppConfig>              <scanIntervalSeconds>4</scanIntervalSeconds>              <connectors>                  <connector implementation="org.eclipse.jetty.server.nio.SelectChannelConnector">                      <port>8083</port>                      <maxIdleTime>60000</maxIdleTime>                  </connector>              </connectors>          </configuration>      </plugin>    </plugins>  </build></project>

 

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

<?xml version="1.0" encoding="UTF-8"?><web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:jsp="http://java.sun.com/xml/ns/javaee/jsp" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">    <welcome-file-list>        <welcome-file>index.jsp</welcome-file>    </welcome-file-list>    <filter>        <filter-name>ssoClientFilter</filter-name>        <filter-class>com.cloud.sso.pro.filter.SSOClientFilter</filter-class>    </filter>    <filter-mapping>        <filter-name>ssoClientFilter</filter-name>        <url-pattern>/*</url-pattern>    </filter-mapping>    <servlet>        <servlet-name>list</servlet-name>        <servlet-class>com.cloud.sso.pro.servlet.ProServlet</servlet-class>    </servlet>    <servlet-mapping>        <servlet-name>list</servlet-name>        <url-pattern>/list</url-pattern>    </servlet-mapping></web-app>

 

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：

 
 

 

工程源代码供下载：

 

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