1. 認(rèn)證流程
基于Session認(rèn)證方式的流程是,用戶認(rèn)證成功后,在服務(wù)端生成用戶相關(guān)的數(shù)據(jù)保存在session中(當(dāng)前會(huì)話)中,發(fā)給客戶端對(duì)應(yīng)的session_id存放到cookie中,這樣用戶請(qǐng)求時(shí)帶上session_id就可以驗(yàn)證服務(wù)器端是否存在session數(shù)據(jù),以完成用戶的合法校驗(yàn),當(dāng)用戶退出系統(tǒng)或session過期銷毀時(shí),客戶端的session_id也就無效了。

基于Session的認(rèn)證機(jī)制由Servlet規(guī)范定制,Servlet容器已經(jīng)實(shí)現(xiàn),用戶通過HttpSession的操作方式即可實(shí)現(xiàn),如下是HttpSession相關(guān)的操作API:

2. 創(chuàng)建工程
本案例工程使用maven進(jìn)行構(gòu)建,使用SpringMVC、Servlet3.0實(shí)現(xiàn)。
2.1 創(chuàng)建maven工程
創(chuàng)建maven工程security-springmvc,工程結(jié)構(gòu)如下:

2.2 Spring容器配置
在config包下定義ApplicationConfig,它對(duì)應(yīng)web.xml中的ContextLoaderListener
/**
* 相當(dāng)于apllicationContext.xml配置文件
*/
@Configuration
@ComponentScan(basePackages = "com.pengjs.book.admin.security",
excludeFilters = {@ComponentScan.Filter(type = FilterType.ANNOTATION, value = Controller.class)})
public class ApplicationConfig {
// 配置除了Controller的其他bean,如:數(shù)據(jù)庫(kù)連接池、事務(wù)管理器、業(yè)務(wù)bean等
}
2.3 ServletContext配置
本案例采用Servlet3.0無web.xml方式,在config包下定義WebConfig,它對(duì)應(yīng)于DispatcherServlet配置
/**
* 相當(dāng)于springmvc.xml配置文件
*/
@Configuration
@EnableWebMvc
@ComponentScan(basePackages = "com.pengjs.book.admin.security",
includeFilters = {@ComponentScan.Filter(type = FilterType.ANNOTATION, value = Controller.class)})
public class WebConfig implements WebMvcConfigurer {
@Autowired
private SimpleAuthenticationInterceptor simpleAuthenticationInterceptor;
/**
* 配置視圖解析器
* @return
*/
@Bean
public InternalResourceViewResolver viewResolver() {
InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
viewResolver.setPrefix("/WEB-INF/view/");
viewResolver.setSuffix(".jsp");
return viewResolver;
}
@Override
public void addViewControllers(ViewControllerRegistry registry) {
// 將"/"定向到"/login"
registry.addViewController("/").setViewName("login");
}
/**
* 添加攔截器,讓攔截器生效
* @param registry
*/
@Override
public void addInterceptors(InterceptorRegistry registry) {
// login接口不攔截,只攔截:/r/**
registry.addInterceptor(simpleAuthenticationInterceptor).addPathPatterns("/r/**");
}
}
2.4 加載Spring容器
在init包下定義Spring容器初始化類SpringApplicationInitializer,此類實(shí)現(xiàn)WebApplicationInitializer接口,Spring容器啟動(dòng)時(shí)加載WebApplicationInitializer接口的所有實(shí)現(xiàn)類。
public class SpringApplicationInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
/**
* spring容器,相當(dāng)于加載apllicationContext.xml
* @return
*/
@Override
protected Class<?>[] getRootConfigClasses() {
// 指定rootContext的配置類
return new Class<?>[]{ApplicationConfig.class};
}
/**
* servletContext,相當(dāng)于加載springmvc.xml配置文件
* @return
*/
@Override
protected Class<?>[] getServletConfigClasses() {
// 指定servletContext的配置類
return new Class<?>[]{WebConfig.class};
}
/**
* url-mapping
* @return
*/
@Override
protected String[] getServletMappings() {
return new String[] {"/"};
}
}
SpringApplicationInitializer相當(dāng)于web.xml,使用了Servlet3.0開發(fā)則不需要要再定義web.xml,ApplicationConfig對(duì)應(yīng)以下配置的application-context.xml,WebConfig對(duì)應(yīng)以下配置的spring-mvc.xml,web.xml的參考內(nèi)容:
<web-app>
<listener>
<listner-class>
org.springframework.web.context.ContextLoaderListener
</listner-class>
</listener>
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/application-context.xml</param-value>
</context-param>
<servlet>
<servlet-name>springmvc</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/spring-mvc.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>springmvc</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>
2.5 實(shí)現(xiàn)認(rèn)證功能
2.5.1 認(rèn)證頁面
在webapp/WEB-INF/view下定義login.jsp,本案例知識(shí)測(cè)試認(rèn)證流程,沒有添加css樣式,頁面實(shí)現(xiàn)可填入用戶名、密碼,觸發(fā)登錄提交表單信息至/login,內(nèi)容如下:
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>用戶登錄</title>
</head>
<body>
<form action="login" method="post">
用戶名:<input type="text" name="username"><br>
密 碼:<input type="password" name="password"><br>
<input type="submit" value="登錄">
</form>
</body>
</html>
在WebConfig中添加如下配置,將“/”直接定向到login.jsp頁面:
@Override
public void addViewControllers(ViewControllerRegistry registry) {
// 將"/"定向到"/login"
registry.addViewController("/").setViewName("login");
}
2.5.2 啟動(dòng)項(xiàng)目
pom配置:
<?xml version="1.0" encoding="UTF-8"?>
<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/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.pengjs.book.admin.security</groupId>
<artifactId>security-springmvc</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>war</packaging>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>5.1.5.RELEASE</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
<!-- 將來需要實(shí)用tomcat容器運(yùn)行,所以scope為provided -->
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.8</version>
</dependency>
</dependencies>
<build>
<finalName>security-springmvc</finalName>
<pluginManagement>
<plugins>
<plugin>
<groupId>org.apache.tomcat.maven</groupId>
<artifactId>tomcat7-maven-plugin</artifactId>
<version>2.2</version>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.1</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
<plugin>
<artifactId>maven-resources-plugin</artifactId>
<version>3.0.2</version>
<configuration>
<encoding>utf-8</encoding>
<useDefaultDelimiters>true</useDefaultDelimiters>
<resources>
<resource>
<directory>src/main/resources</directory>
<filtering>true</filtering>
<includes>
<include>**/*</include>
</includes>
</resource>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.xml</include>
</includes>
</resource>
</resources>
</configuration>
</plugin>
</plugins>
</pluginManagement>
</build>
</project>
配置maven啟動(dòng):


2.5.3 認(rèn)證接口
用戶進(jìn)入認(rèn)證頁面,熟肉賬號(hào)和密碼,點(diǎn)擊登錄,請(qǐng)求/login進(jìn)行身份認(rèn)證。
- 定義認(rèn)證接口,此接口用于對(duì)傳來的用戶名、密碼校驗(yàn),若成功則返回該用戶的詳細(xì)信息,否則拋出異常:
public interface AuthenticationService {
/**
* 用戶認(rèn)證,校驗(yàn)用戶信息是否合法
* @param authenticationRequest 用戶認(rèn)證請(qǐng)求,賬號(hào)和密碼
* @return 認(rèn)證成功后的用戶信息
*/
UserDto authentication(AuthenticationRequest authenticationRequest);
}
- 認(rèn)證請(qǐng)求結(jié)構(gòu):
/**
* 用戶身份信息
*/
@Data
public class AuthenticationRequest {
/**
* 用戶名
*/
private String username;
/**
* 密碼
*/
private String password;
}
- 認(rèn)證成功后返回的用戶詳細(xì)信息,也就是當(dāng)前登錄用戶的信息:
@Data
@AllArgsConstructor
@NoArgsConstructor
public class UserDto {
public static final String SESSION_USER_KEY = "_user";
private String id;
private String username;
private String password;
private String fullname;
private String mobile;
/**
* 用戶權(quán)限
*/
private Set<String> authorities;
}
- 認(rèn)證接口實(shí)現(xiàn)類
AuthenticationServiceImpl:
@Service
public class AuthenticationServiceImpl implements AuthenticationService {
@Override
public UserDto authentication(AuthenticationRequest authenticationRequest) {
// 校驗(yàn)參數(shù)是否為空
if (null == authenticationRequest || StringUtils.isEmpty(authenticationRequest.getUsername())
|| StringUtils.isEmpty(authenticationRequest.getPassword())) {
throw new RuntimeException("賬號(hào)密碼為空");
}
UserDto userDto = getUserDto(authenticationRequest.getUsername());
// 判斷用戶是否為空
if (null == userDto) {
throw new RuntimeException("查詢不到該用戶");
}
// 校驗(yàn)密碼
if (!authenticationRequest.getPassword().equals(userDto.getPassword())) {
throw new RuntimeException("賬號(hào)或者密碼錯(cuò)誤");
}
// 認(rèn)證通過
return userDto;
}
/**
* 模擬用戶查詢
*
* @param username 用戶名
* @return UserDto
*/
private UserDto getUserDto(String username) {
return userMap.get(username);
}
private Map<String, UserDto> userMap = new HashMap<>();
{
// 不同的用戶,不同的權(quán)限
Set<String> authorities1 = new HashSet<>();
// p1權(quán)限標(biāo)識(shí)符,和/r/r1對(duì)應(yīng)
authorities1.add("p1");
// p2權(quán)限標(biāo)識(shí)符,和/r/r2對(duì)應(yīng)
Set<String> authorities2 = new HashSet<>();
authorities2.add("p2");
userMap.put("zhangsan", new UserDto("1000", "zhangsan", "123", "張三", "133433", authorities1));
userMap.put("lisi", new UserDto("1011", "lisi", "456", "李四", "144553", authorities2));
}
}
-
LoginController:
@RestController
public class LoginController {
@Autowired
private AuthenticationService authenticationService;
@PostMapping(value = "/login", produces = "text/plain;charset=utf-8")
public String login(AuthenticationRequest authenticationRequest, HttpSession session) {
UserDto userDto = authenticationService.authentication(authenticationRequest);
// 存入session
session.setAttribute(UserDto.SESSION_USER_KEY, userDto);
return userDto.getFullname() + "登錄成功";
}
}
2.6 實(shí)現(xiàn)會(huì)話功能
會(huì)話是指用戶登錄系統(tǒng)后,系統(tǒng)會(huì)記住該用戶的登錄狀態(tài),他可以在系統(tǒng)連續(xù)操作直到退出系統(tǒng)的過程。
認(rèn)證的目的是對(duì)系統(tǒng)資源的保護(hù),每次對(duì)資源的訪問,系統(tǒng)必須得直到是誰在訪問資源,才能對(duì)該請(qǐng)求進(jìn)行合法攔截。因此,在認(rèn)證成功后,一般會(huì)把認(rèn)證后的用戶信息放入Session中,在后續(xù)的請(qǐng)求中,系統(tǒng)能夠從Session中獲取到當(dāng)前用戶,用這樣的方式來實(shí)現(xiàn)會(huì)話機(jī)制。
- 增加會(huì)話控制
首先在UserDto中定義一個(gè)SESSION_USER_KEY,作為Session中存放登錄用戶信息的key。
public static final String SESSION_USER_KEY = "_user";
- 然后在
LoginController中,認(rèn)證成功后,將用戶信息放入當(dāng)前會(huì)話。并增加用戶登出方法,登出時(shí)session只為無效。
/**
* 退出登錄
* @param session
* @return
*/
@GetMapping(value = "logout", produces = {"text/plain;charset=utf-8"})
public String logout(HttpSession session) {
session.invalidate();
return "退出成功";
}
-
LoginController中增加測(cè)試資源,如果已經(jīng)登錄過則會(huì)在session中獲取“_user”對(duì)應(yīng)的UserDto信息,否則為空。
/**
* 測(cè)試資源1
* @param session
* @return
*/
@GetMapping(value = "/r/r1", produces = {"text/plain;charset=utf-8"})
public String r1(HttpSession session) {
String fullname = null;
Object userObj = session.getAttribute(UserDto.SESSION_USER_KEY);
if (null != userObj) {
fullname = ((UserDto) userObj).getFullname();
} else {
fullname = "匿名";
}
return fullname + " 訪問資源1";
}
2.7 實(shí)現(xiàn)授權(quán)功能
現(xiàn)在我們已經(jīng)完成了用戶身份憑證及登錄的狀態(tài)保持,并且也知道了如何獲取當(dāng)前登錄用戶(從session中獲取)的信息,接下來,用具訪問系統(tǒng)需要經(jīng)過授權(quán),即需要完成以下功能:
- 匿名用戶(未登錄用戶)訪問攔截:禁止匿名用戶訪問某些資源。
- 登錄用戶訪問攔截:根據(jù)用戶的權(quán)限決定能否訪問某些資源。
- 增加權(quán)限數(shù)據(jù)
為了實(shí)現(xiàn)這樣的功能,需要在UserDto中增加權(quán)限屬性,用于表示該登錄用戶所擁有的權(quán)限:

- 在
AuthenticationServiceImpl中為模擬用戶初始化權(quán)限,其中給了張三p1權(quán)限,給了李四p2權(quán)限。

- 編寫攔截器
SimpleAuthenticationInterceptor
@Component
public class SimpleAuthenticationInterceptor implements HandlerInterceptor {
/**
* 調(diào)用Controller之前攔截
* 校驗(yàn)用戶請(qǐng)求的URL是否在用戶的權(quán)限范圍內(nèi)
* @param request
* @param response
* @param handler
* @return
* @throws Exception
*/
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
// 取出用戶身份信息
Object object = request.getSession().getAttribute(UserDto.SESSION_USER_KEY);
if (null == object) {
// 沒有認(rèn)證,提示登錄
writeContent(response, "請(qǐng)登錄");
return false;
}
UserDto userDto = (UserDto) object;
// 根據(jù)請(qǐng)求的URL
String requestURI = request.getRequestURI();
if (userDto.getAuthorities().contains("p1") && requestURI.contains("/r/r1")) {
return true;
}
if (userDto.getAuthorities().contains("p2") && requestURI.contains("/r/r2")) {
return true;
}
writeContent(response, "沒有權(quán)限,拒絕訪問");
return false;
}
/**
* 響應(yīng)信息給前端
* @param response
* @param msg
*/
private void writeContent(HttpServletResponse response, String msg) throws IOException {
response.setContentType("text/html;charset=utf-8");
PrintWriter writer = response.getWriter();
writer.write(msg);
writer.close();
}
}
-
WebConfig中注冊(cè)攔截器,是攔截器生效:

3. 小結(jié)
基于Session的認(rèn)證方式是一種常見的認(rèn)證方式,至今還有非常多的系統(tǒng)在使用。而在正常項(xiàng)目中,我們往往會(huì)考慮使用第三方安全框架(如spring security,shiro等)來實(shí)現(xiàn)認(rèn)證授權(quán)功能,因?yàn)檫@樣能一定程度提高生產(chǎn)力,提高軟件標(biāo)準(zhǔn)化程度,另外,這下框架的可擴(kuò)展性考慮的非常全面。但是缺點(diǎn)也非常明顯,這些同用戶組件為了提高支持范圍會(huì)增加很多可能不需要的功能,結(jié)構(gòu)上也會(huì)比較抽象,如果不了解它,一旦出現(xiàn)問題,將很難定位。