SpringMVC 如何使用注解完成登录拦截

目录

• 为了实现用户登录拦截你是否写过如下代码呢?

• 1. 基于Filter

• 2. 基于Struts

• 3. 基于SpringMVC

• 如何使用自定义注解完成自定义拦截呢？

• 登录注解

• SpringMVC * 设置

• 最终 controller 写法

• 1. 不需要登录权限的

• 2. 整个 controller 内都需要登录权限

• 3. controller 某个方法需要登录权限

为了实现用户登录拦截你是否写过如下代码呢?

1. 基于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.HttpServletRequest;
import javax.servlet.http.HttpSession;

public class AuthenticationFilter implements Filter {
private FilterConfig filterConfig;
private String onErrorUrl;

public void init(FilterConfig filterConfig) throws ServletException {
// 从 filterConfig 中的得到错误页
this.filterConfig = filterConfig;
this.onErrorUrl = filterConfig.getInitParameter("onError");
if(this.onErrorUrl == null || "".equals(this.onErrorUrl))
this.onErrorUrl = "onError";
}

public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {

HttpServletRequest httpRequest = (HttpServletRequest)request;
session = httpRequest.getSession();
if(null == session.getAttribute("_LOGIN_USER_") && !"/login".equals(httpRequest.getServletPath())) {
httpRequest.getRequestDispatcher("/"+this.onErrorUrl).forward(request, response);
}else{
chain.doFilter(request, response);
}
}

public void destroy() {

}

}

2. 基于Struts

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.interceptor.AbstractInterceptor;

@SuppressWarnings("serial")
public class LoginInterceptor extends AbstractInterceptor {

@Override
public String intercept(ActionInvocation invocation) throws Exception {
String currentUser="currentUser";
HttpServletRequest request=ServletActionContext.getRequest();
HttpServletResponse response=ServletActionContext.getResponse();
HttpSession session=request.getSession();
 if(request.getRequestURI().endsWith("login.action")){
  return invocation.invoke();
 } else {
if(session.getAttribute(currentUser)!=null){
return invocation.invoke();
}else{
response.sendRedirect(request.getContextPath()+"/login.jsp");
}
 }
return null;
}
}

3. 基于SpringMVC

import javax.servlet.RequestDispatcher;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import cn.edu.hdc.util.Constants;

/**
* @ClassName: LoginInterceptor
* @Description: 登录 *
* @author loweir hbloweir@163.com
* @date 2016年4月27日 上午8:06:11
*/
public class LoginInterceptor implements HandlerInterceptor {
/**
* 在目标方法前被调用，返回 true 继续
*/
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object obj) throws Exception {
try {
String url = request.getRequestURI();
// 如果不是登录操作 判断 session
if (!url.endsWith("login")) {
if (request.getSession().getAttribute(Constants.CURRENT_USER) == null) {
 response.sendRedirect(request.getContextPath() + "/login.jsp");
return false;
}
}}
return true;
} catch (Exception e) {
e.printStackTrace();
return false;
}
}

@Override
public void afterCompletion(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, Exception arg3)
throws Exception {
}

@Override
public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, ModelAndView arg3)
throws Exception {

}
}

如何使用自定义注解完成自定义拦截呢？

登录注解

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
* Created by loweir on 2017/5/14 17:19
* <p>
* author: 张瑀楠
* email: hbloweir@163.com
* 负责登录拦截
*/
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE,ElementType.METHOD})
public @interface WebLoginRequired {
String value() default ""; // 未登录时需要跳转的路径
}

SpringMVC * 设置

import com.ainsoft.globalshoperp.component.constant.WebLogin;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
* Created by loweir on 2017/5/14 17:14
* <p>
* author: 张瑀楠
* email: hbloweir@163.com
*/
public class LoginInterceptor implements HandlerInterceptor {

private static Log logger = LogFactory.getLog(LoginInterceptor.class);

public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object handler) throws Exception {

if (logger.isDebugEnabled()) {
  logger.debug(" * 启动");
 }
 /*
 * 判断是否为 HandlerMethod.class
 * 如果不是说明当前请求并不是 SpringMVC 管理，
 * 如果不是再自行根据业务做响应操作，这里直接返回 true
 */
 if (HandlerMethod.class.isInstance(handler)) {
  HandlerMethod handlerMethod = (HandlerMethod) handler;

// 判断该 handler 是否有WebLoginRequired注解
  WebLoginRequired webLoginRequired = handlerMethod.getMethod().getDeclaredAnnotation(WebLoginRequired.class);

// 如果该 handler 没有WebLoginRequired注解，判断所属Controller 是否包含注解
  if (null == webLoginRequired) {
   webLoginRequired = handlerMethod.getBeanType().getAnnotation(WebLoginRequired.class);
  }

// 如果需要 WebLoginRequired 判断 session
  if (null != webLoginRequired) {
   if (httpServletRequest.getSession().getAttribute(WebLogin.CURRENTUSER) == null) {
    String executeURL = webLoginRequired.value();
    if (StringUtils.isBlank(executeURL)) {
     executeURL = WebLogin.LOGIN;
    }

httpServletResponse.sendRedirect(httpServletRequest.getContextPath() + executeURL);
    return false;
   }
  }
 }
 return true;
}

public void postHandle(javax.servlet.http.HttpServletRequest httpServletRequest, javax.servlet.http.HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
 if (logger.isDebugEnabled()) {
  logger.debug("postHandler");
 }
}

public void afterCompletion(javax.servlet.http.HttpServletRequest httpServletRequest, javax.servlet.http.HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
 if (logger.isDebugEnabled()) {
  logger.debug("afterCompletion");
 }
}
}

最终 controller 写法

1. 不需要登录权限的

类和方法都不需要注解

@Controller
@RequestMapping("auth")
public class AuthController {

@RequestMapping("login")
public String login() {
 return "login";
}
}

2. 整个 controller 内都需要登录权限

在类上添加注解即可

@Controller
@WebLoginRequired
@RequestMapping("order")
public class OrderController {

@RequestMapping("index")
public String index() {
 return "index";
}
}

3. controller 某个方法需要登录权限

只在需要登录权限的方法上添加注解
在注解上可以指定需要重定向的链接
如果不指定则默认到 login

@Controller
@RequestMapping("order")
public class OrderController {

@RequestMapping("index")
public String index() {
 return "index";
}

// 需要登录
@WebLoginRequired
@RequestMapping("add")
public String index() {
 return "index";
}

// 需要登录,如果未登录跳到 error
@WebLoginRequired("error")
@RequestMapping("delete")
public String index() {
 return "index";
}
}

来源：https://www.cnblogs.com/zyndev/p/7613006.html