SpringMVC 视图解析器 方法返回值 异常处理器

@Configuration
@ComponentScan(basePackages="com.czxy.mvc.controller")
@EnableWebMvc
public class MvcConfiguration implements WebMvcConfigurer {
    @Override
    public void configureViewResolvers(ViewResolverRegistry registry) {
        registry.jsp("/pages/",".jsp");
    }
}

@Controller
@RequestMapping("/user")
public class UserController {

    @RequestMapping("/selectAll2")
    public String selectAll2() {
        return "list";
    }
}

@Controller 
@RequestMapping("/user") 
public class UserController {
    /**
     * 最终访问路径 /user/selectAll.action
     * @return
     */
    @RequestMapping("/selectAll")
    public String selectAll() {
        return "forward:/pages/list.jsp";
    }
}

@Controller
@RequestMapping("/demo03")
public class Demo03BookController {

    @RequestMapping("/list")
    public ModelAndView list() {

        //1 创建对象
        ModelAndView modelAndView = new ModelAndView();
        //2 设置视图
        modelAndView.setViewName("book");       //之前 return "book";
        //3 设置模型数据 key-value
        modelAndView.addObject("username","jack");

        return modelAndView;
    }

}

public String list() {
    return "forward:物理视图";		//jsp路径
}

public String list() {
    return "redirect:物理视图";		//jsp路径
}

    @RequestMapping("/void1")
    public void void1() {
        System.out.println("void1 执行了 ");
    }

@RequestMapping("/void2")
public void void2(HttpServletRequest request , HttpServletResponse response) throws Exception {

	request.setAttribute("username","void2");
	// 请求转发
	request.getRequestDispatcher("/WEB-INF/pages/book.jsp").forward(request, response);

	// 请求包含
	//request.getRequestDispatcher("/WEB-INF/pages/book.jsp").include(request, response);
}

    @RequestMapping("/void3")
    public void void3(HttpServletRequest request , HttpServletResponse response) throws Exception {
        response.getWriter().print("void3");
    }

    @RequestMapping("/void4")
    @ResponseBody
    public void void4() throws Exception {
        System.out.println("哈哈");
    }

public class CustomExcption extends RuntimeException {
    public CustomExcption() {
    }

    public CustomExcption(String message) {
        super(message);
    }

    public CustomExcption(String message, Throwable cause) {
        super(message, cause);
    }

    public CustomExcption(Throwable cause) {
        super(cause);
    }

    public CustomExcption(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {
        super(message, cause, enableSuppression, writableStackTrace);
    }
}

@Controller
@RequestMapping("/demo04")
public class Demo04ItemController {

    @RequestMapping("/item")
    public String item(Integer id ) {
        if(id == 1) {
            // 系统异常
            int i = 1 / 0;
        } else if( id == 2 ) {
            // 自定义
            throw new CustomExcption("自定义异常信息");
        }
        //正常
        return "forward:/index.jsp";
    }
}

<a href="${pageContext.request.contextPath}/demo04/item.action?id=1">异常处理 id =1 系统异常</a> <br/>
<a href="${pageContext.request.contextPath}/demo04/item.action?id=2">异常处理 id =2 自定义异常 </a> <br/>
<a href="${pageContext.request.contextPath}/demo04/item.action?id=3">异常处理正常</a> <br/>

@Component
public class CustomExceptionResolver  implements HandlerExceptionResolver {
    @Override
    public ModelAndView resolveException(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) {
        // 1 统一异常
        CustomExcption customExcption = null;
        if(e instanceof CustomExcption) {
            customExcption = (CustomExcption) e;
        } else {
            customExcption = new CustomExcption("系统繁忙，请稍后重试！");
        }

        // 2 错误信息返回
        ModelAndView modelAndView = new ModelAndView();
        modelAndView.addObject("message" ,customExcption.getMessage());
        modelAndView.setViewName("forward:/error.jsp");

        return modelAndView;
    }
}

@ControllerAdvice
public class GlobalExceptionResolver {

    /**
     * 自定义异常处理器
     * @param ec
     * @param model
     * @return
     */
    @ExceptionHandler(CustomExcption.class)
    public String custom(CustomExcption ec, Model model) {
        model.addAttribute("message", ec.getMessage() + "Global");
        return "forward:/error.jsp";
    }

    /**
     * 其他异常处理器
     * @param e
     * @param model
     * @return
     */
    @ExceptionHandler(Exception.class)
    public String other(Exception e, Model model) {
        model.addAttribute("message", "系统繁忙，请稍后重试！" + "Global");
        return "forward:/error.jsp";
    }
}

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>友好页面</title>
</head>
<body>
    ${message}
</body>
</html>