Servlet Filter 权限过滤

本文最后更新于：2024年3月18日 凌晨

Servlet Filter 权限过滤

pom.xml

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<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>javax.servlet-api</artifactId>
    <version>4.0.1</version>
    <scope>provided</scope>
</dependency>

代码实现

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@WebFilter(filterName = "loginFilter",
           urlPatterns = "/*",
           initParams = {
               @WebInitParam(name = "loginUI", value = "/home/loginUI"),
               @WebInitParam(name = "loginProcess", value = "home/login"),
               @WebInitParam(name = "encoding", value = "utf-8")
           })
public class LoginFilter implements Filter {
    private FilterConfig config;

    @Override
    public void init(FilterConfig config) throws ServletException {
        this.config = config;
    }


    @Override
    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain)
        throws IOException, ServletException {
        // 获取配置参数。
        String loginUI = config.getInitParameter("loginUI");
        String loginProcess = config.getInitParameter("loginProcess");
        String encoding = config.getInitParameter("encoding");


        HttpServletRequest request = (HttpServletRequest) req;
        HttpServletResponse response = (HttpServletResponse) res;

        // 设置请求的字符集（post请求方式有效）
        request.setCharacterEncoding(encoding);

        // 不带http:// 域名：端口的地址。
        String uri = request.getRequestURI();
        if (uri.contains(loginUI) || uri.contains(loginProcess)) {
            // 请求的登录，放行。
            chain.doFilter(request, response);
        } else {
            if (request.getSession().getAttribute("user") == null) {
                // 重定向到登录页面。
                response.sendRedirect(request.getContextPath() + loginUI);
            } else {
                // 已经登录，放行。
                chain.doFilter(request, response);
            }
        }
    }

    @Override
    public void destroy() {
        this.config = null;
    }
}