通过Spring security进行权限设置

当一个网页被访问时，有时候希望对于不同的用户给予不同的访问权限。比如管理员用户可以对数据库进行一些增删改操作，而只留给普通用户查询的操作，隐藏了其他功能。我们可以使用Spring security 来实现

1.导入jar包

如下在maven的pom.xml中添加下面信息，自动下载jar包。也可以手动导入jar包

<spring.security.version>5.0.1.RELEASE</spring.security.version>

 <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-web</artifactId>
            <version>${spring.security.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-config</artifactId>
            <version>${spring.security.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-core</artifactId>
            <version>${spring.security.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-taglibs</artifactId>
            <version>${spring.security.version}</version>
        </dependency>

2.添加过滤器

在web.xml中添加

<filter>
    <filter-name>springSecurityFilterChain</filter-name>
    <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
  </filter>
  <filter-mapping>
    <filter-name>springSecurityFilterChain</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>

3.写spring security配置文件，并在web.xml中加载

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:security="http://www.springframework.org/schema/security"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/security
    http://www.springframework.org/schema/security/spring-security.xsd">

    <security:global-method-security pre-post-annotations="enabled" jsr250-annotations="enabled" secured-annotations="enabled"></security:global-method-security>

    <!-- 配置不拦截的资源 -->
    <security:http pattern="/login.jsp" security="none"/>
    <security:http pattern="/failer.jsp" security="none"/>
    <security:http pattern="/css/**" security="none"/>
    <security:http pattern="/img/**" security="none"/>
    <security:http pattern="/plugins/**" security="none"/>
    <!--
    	配置具体的规则
    	auto-config="true"	不用自己编写登录的页面，框架提供默认登录页面
    	use-expressions="false"	是否使用SPEL表达式（没学习过）
    -->
    <security:http auto-config="true" use-expressions="true">
        <!-- 配置具体的拦截的规则 pattern="请求路径的规则" access="访问系统的人，必须有ROLE_USER的角色" -->
        <security:intercept-url pattern="/**" access="hasRole('ROLE_ADMIN')"/>

        <security:form-login login-page="/login.jsp"
                             login-processing-url="/login.do"
                            default-target-url="/index.jsp"
                            authentication-failure-url="/failer.jsp"
                            authentication-success-forward-url="/pages/main.jsp"/>

        <!-- 关闭跨域请求 -->
        <security:csrf disabled="true"/>

        <!--退出并跳转到首页-->
        <security:logout invalidate-session="true" logout-url="/logout.do" logout-success-url="/login.jsp"></security:logout>

    </security:http>

    <!-- 切换成数据库中的用户名和密码 -->
    <security:authentication-manager>
        <security:authentication-provider user-service-ref="userService">

            <!-- 配置加密的方式
            <security:password-encoder ref="passwordEncoder"/>　-->
        </security:authentication-provider>
    </security:authentication-manager>

    <!-- 配置加密类 -->
    <bean id="passwordEncoder" class="org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder"></bean>
    <!-- <bean id="webexpressionHandler" class="org.springframework.security.web.access.expression.DefaultWebSecurityExpressionHandler" />-->
    <!-- 提供了入门的方式，在内存中存入用户名和密码
    <security:authentication-manager>
    	<security:authentication-provider>
    		<security:user-service>
    			<security:user name="admin" password="{noop}admin" authorities="ROLE_USER"/>
    		</security:user-service>
    	</security:authentication-provider>
    </security:authentication-manager>
    -->

</beans>

在web.xml中添加：
<context-param> <param-name>contextConfigLocation</param-name> <param-value>classpath*:spring-security.xml</param-value> </context-param>

4.service层继承UserDetailsService类，改写方法（绕过了controller层的登陆管理）

 @Override
    public UserDetails loadUserByUsername(String name) {

        UserInfo userInfo= userDao.findByUserName(name);
        User user=null;
        if(userInfo!=null){

            List<Role> roles = roleDao.findRoleByUserId(userInfo.getId());
            userInfo.setRoleList(roles);
            user=new User(userInfo.getUsername(),"{noop}"+userInfo.getPassword(),getAuthority(roles));
        }
        return user;
    }

    private List<SimpleGrantedAuthority> getAuthority(List<Role> roles) {
        List<SimpleGrantedAuthority> list=new ArrayList<>();
        for(Role role:roles){
            list.add(new SimpleGrantedAuthority("ROLE_"+role.getRolename()));
        }
        return list;
    }
``

##  5.改写jsp页面
这个就是根据spring security的配置文件，改写相应的路径以及传参即可