Spring学习笔记（十）——SpringMVC框架中的拦截器和异常处理

package cn.kt.Interceptor;/*
 *Created by tao on 2020-04-11.
 */

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

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


/*
 * 自定义拦截器案例
 * */
public class MyInterceptor implements HandlerInterceptor {

    /**
     * 预处理，controller方法执行前
     * return false不放行
     * return true 放行，执行下一个拦截器
     *
     * @param request
     * @param response
     * @return
     * @throws Exception
     */
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("111拦截器执行了...前");
        return true;
    }

    /**
     * 后执行方法，在controller执行之后执行
     *
     * @param request
     * @param response
     * @param handler
     * @param modelAndView
     * @throws Exception
     */
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("111后执行方法执行了，，，后");
    }

    /**
     * 最后执行方法，在页面跳转完之后执行
     *
     * @param request
     * @param response
     * @param handler
     * @param ex
     * @throws Exception
     */
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable Exception ex) throws Exception {
        System.out.println("111最后执行的方法执行了，，，最后");
    }


}

<!--配置拦截器-->
    <mvc:interceptors>
        <mvc:interceptor>
            <!-- 哪些方法进行拦截 -->
            <mvc:mapping path="/ipc/**"/>
            <!-- 哪些方法不进行拦截
            <mvc:exclude-mapping path=""/>
            -->
            <!-- 注册拦截器对象 -->
            <bean class="cn.kt.Interceptor.MyInterceptor"/>
        </mvc:interceptor>
    </mvc:interceptors>

package cn.kt.exception;/*
 *Created by tao on 2020-04-11.
 */
/*
* 自定义异常类
* */
public class SysException extends Exception{
    private static final long serialVersionUID = 4055945147128016300L;
    // 异常提示信息
    private String message;
    public String getMessage() {
        return message;
    }
    public void setMessage(String message) {
        this.message = message;
    }
    public SysException(String message) {
        this.message = message;
    }
}

package cn.kt.controller;/*
 *Created by tao on 2020-04-11.
 */

import cn.kt.exception.SysException;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
@RequestMapping("/exc")
public class ExceptionController {

    @RequestMapping("/testException")
    public  String testException() throws SysException {
        System.out.println("testException方法执行了，，，");
        try {
            //模拟异常
            int a= 1/0;
        } catch (Exception e) {
            //控制台打印异常
            e.printStackTrace();
            //抛出自定义异常
            throw new SysException("testException出现错误");
        }
        return "success";
    }
}

package cn.kt.exception;/*
 *Created by tao on 2020-04-11.
 */

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

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

/**
 * 异常处理器
 *
 * @author rt
 */
public class SysExceptionResolver implements HandlerExceptionResolver {
    /**
     * 处理异常的业务逻辑
     * 跳转到具体的错误页面的方法
     */
    public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {
        ex.printStackTrace();
        SysException e = null;
        // 获取到异常对象
        if (ex instanceof SysException) {
            e = (SysException) ex;
        } else {
            e = new SysException("系统正在维护");
        }
        ModelAndView mv = new ModelAndView();
        // 存入错误的提示信息
        mv.addObject("errorMsg", e.getMessage());
        // 跳转的Jsp页面
        mv.setViewName("error");
        return mv;
    }
}

 <!-- 配置异常处理器 -->
    <bean id="sysExceptionResolver" class="cn.kt.exception.SysExceptionResolver"/>