@WebServlet("/test")
public class TestServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) {
        try {
            resp.getWriter().println("hello servlet!!");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

public class FirstController implements Controller {

    public ModelAndView handleRequest(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws Exception {
        // ModelAndView 封装了模型和视图
        ModelAndView mv = new ModelAndView();
        // 模型里封装数据
        mv.addObject("hellomvc","Hello springMVC!");
        // 封装跳转的视图名字
        mv.setViewName("hellomvc");
        // 不是有个视图解析器吗？
        // 这玩意可以自动给你加个前缀后缀，可以将hellomvc拼装成/jsp/hellomvc.jsp
        return mv;
    }
}

@Controller
public class AnnotationController {

    @RequestMapping("/hello")
    public ModelAndView testAnnotation(){
        ModelAndView modelAndView = new ModelAndView();
        modelAndView.addObject("hello","hello annotationMvc");
        modelAndView.setViewName("hello");
        return modelAndView;
    }

}

protected void doDispatch(HttpServletRequest request, HttpServletResponse response) throws Exception {
        HttpServletRequest processedRequest = request;
        HandlerExecutionChain mappedHandler = null;
        boolean multipartRequestParsed = false;

        WebAsyncManager asyncManager = WebAsyncUtils.getAsyncManager(request);

        try {
            ModelAndView mv = null;
            Exception dispatchException = null;

            try {
                // 判断请求中有没有文件
                processedRequest = checkMultipart(request);
                multipartRequestParsed = (processedRequest != request);

                // 获得一个过滤器链，这就是处理器适配器的工作
                mappedHandler = getHandler(processedRequest);
                if (mappedHandler == null) {
                    noHandlerFound(processedRequest, response);
                    return;
                }

                // 确定当前请求的处理程序适配器   
                HandlerAdapter ha = getHandlerAdapter(mappedHandler.getHandler());

                // 省略一些
                ...

                // 处理器链调用所有拦截器的前置处理程序，如有不满足的直接返回：
                if (!mappedHandler.applyPreHandle(processedRequest, response)) {
                    return;
                }

                // 此处由处理器适配器调用我们写的controller。
                mv = ha.handle(processedRequest, response, mappedHandler.getHandler());

                if (asyncManager.isConcurrentHandlingStarted()) {
                    return;
                }

                applyDefaultViewName(processedRequest, mv);
                // 处理器链调用所有拦截器的后置处理程序，如有不满足的直接返回：
                mappedHandler.applyPostHandle(processedRequest, response, mv);
            }
            catch (Exception ex) {
                dispatchException = ex;
            }
            catch (Throwable err) {
                dispatchException = new NestedServletException("Handler dispatch failed", err);
            }
            // 处理最终结果，视图解析器处理mv，还要做统一的异常处理
            processDispatchResult(processedRequest, response, mappedHandler, mv, dispatchException);
        }
    ...
    }

public interface HandlerInterceptor {
    //处理器执行之前
    default boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        return true;
    }
    //处理器执行之后
    default void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable ModelAndView modelAndView) throws Exception {
    }
    //完成之后
    default void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable Exception ex) throws Exception {
    }
}

@RequestMapping("/test1")
public String testAnnotation(Model model){
    model.addAttribute("hello","hello annotationMvc as string");
    return "annotation";
}

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

    @RequestMapping("register")
    public String register(Model model){
        ......
        return "register";
    }

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

@RequestMapping(value = "add",method = RequestMethod.POST,
                consumes = "application/json",produces = "text/plain",
                headers = "name",params = {"age","times"}
               )
@ResponseBody
public String add(Model model){
    model.addAttribute("user","add user");
    return "user";
}

@GetMapping("getOne")
public String getOne(){
    return "user";
}

@PostMapping("insert")
public String insert(){
    return "user";
}

@PutMapping("update")
public String update(){
    return "user";
}

@DeleteMapping("delete")
public String delete(){
    return "user";
}

@RequestMapping(
    method = {RequestMethod.GET}
)
public @interface GetMapping {

@GetMapping("/owners/{ownerId}/pets/{petId}")
public Pet findPet(@PathVariable Long ownerId, @PathVariable Long petId) {
    // ...
}

@Controller
@RequestMapping("/owners/{ownerId}")
public class OwnerController {

    @GetMapping("/pets/{petId}")
    public Pet findPet(@PathVariable Long ownerId, @PathVariable Long petId) {
        // ...
    }
}

protected static class AntPatternComparator implements Comparator<String> {

    @Override
    public int compare(String pattern1, String pattern2) {
        PatternInfo info1 = new PatternInfo(pattern1);
        PatternInfo info2 = new PatternInfo(pattern2);
        .....

        boolean pattern1EqualsPath = pattern1.equals(this.path);
        boolean pattern2EqualsPath = pattern2.equals(this.path);
        // 完全相等，是无法比较的
        if (pattern1EqualsPath && pattern2EqualsPath) {
            return 0;
        }
        // pattern1和urlequals,返回负数 1胜出
        else if (pattern1EqualsPath) {
            return -1;
        }
        // pattern2和urlequals,返回正数，2胜出
        else if (pattern2EqualsPath) {
            return 1;
        }

        // 都是前缀匹配，长的优先   /a/b/**  /a/**
        if (info1.isPrefixPattern() && info2.isPrefixPattern()) {
            return info2.getLength() - info1.getLength();
        }
        // 非前缀匹配的优先级高
        else if (info1.isPrefixPattern() && info2.getDoubleWildcards() == 0) {
            return 1;
        }
        else if (info2.isPrefixPattern() && info1.getDoubleWildcards() == 0) {
            return -1;
        }

        // 匹配数越少，优先级越高
        if (info1.getTotalCount() != info2.getTotalCount()) {
            return info1.getTotalCount() - info2.getTotalCount();
        }

        // 路径越短越好
        if (info1.getLength() != info2.getLength()) {
            return info2.getLength() - info1.getLength();
        }

        // 单通配符个数，数量越少优先级越高
        if (info1.getSingleWildcards() < info2.getSingleWildcards()) {
            return -1;
        }
        else if (info2.getSingleWildcards() < info1.getSingleWildcards()) {
            return 1;
        }
        // url参数越少越优先
        if (info1.getUriVars() < info2.getUriVars()) {
            return -1;
        }
        else if (info2.getUriVars() < info1.getUriVars()) {
            return 1;
        }

        return 0;
    }
}

@PostMapping("insert")
public String insert(HttpServletRequest req){
    String username = req.getParameter("username");
    String password = req.getParameter("password");
    // 其他操作
    return "success";
}

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

    @RequestMapping("login")
    public String login(String username,String password){
        System.out.println(username);
        System.out.println(password);
        return "login";
    }
}

public class User {

    private String username;
    private String password;
    private int age;

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
}

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

    @RequestMapping("register")
    public String register(User user){
        System.out.println(user);
        return "register";
    }

    @RequestMapping("login")
    public String login(String username,String password){
        System.out.println(username);
        System.out.println(password);
        return "login";
    }
}

@Controller
@RequestMapping("/pets")
public class EditPetForm {

    @GetMapping
    public String setupForm(@RequestParam("petId") int petId, Model model) { 
        Pet pet = this.clinic.loadPet(petId);
        model.addAttribute("pet", pet);
        return "petForm";
    }
}

@GetMapping("/demo")
public void handle(
        @RequestHeader("Accept-Encoding") String encoding, 
        @RequestHeader("Keep-Alive") long keepAlive) { 
    //...
}

@GetMapping("/demo")
public void handle(@CookieValue("JSESSIONID") String cookie) { 
    //...
}

@RequestMapping("/register")
public String register(@ModelAttribute("user") UserForm user) {
    ...
}

@Controller
public class ModelAttributeController {
    // @ModelAttribute和@RequestMapping同时放在方法上
    @RequestMapping(value = "/index")
    @ModelAttribute("name")
    public String model(@RequestParam(required = false) String name) {
        return name;
    }
}

@RequestMapping("/")
public String handle(@SessionAttribute User user) { 
    // ...
}

@GetMapping("/")
public String handle(@RequestAttribute Client client) { 
    // ...
}

@Controller
@RequestMapping("/Demo.do")
@SessionAttributes(value={"attr1","attr2"})
public class Demo {

    @RequestMapping(params="method=index")
    public ModelAndView index() {
        ModelAndView mav = new ModelAndView("index.jsp");
        mav.addObject("attr1", "attr1Value");
        mav.addObject("attr2", "attr2Value");
        return mav;
    }

    @RequestMapping(params="method=index2")
    public ModelAndView index2(@ModelAttribute("attr1")String attr1, @ModelAttribute("attr2")String attr2) {
        ModelAndView mav = new ModelAndView("success.jsp");
        return mav;
    }
}

@RequestMapping("insertUser")
    public String insertUser(
            @RequestParam(value = "age",required = false) Integer age,
            @RequestHeader(value = "Content-Type",required = false) String contentType,
            @RequestHeader(required = false) String name,
            @CookieValue(value = "company",required = false) String company,
            @SessionAttribute(value = "username",required = false) String onlineUser,
            @RequestAttribute(required = false) Integer count,
            @ModelAttribute("date") Date date,
            @SessionAttribute(value = "date",required = false) Date sessionDate
    ) {
        System.out.println("sessionDate = " + sessionDate);
        System.out.println("date = " + date);
        System.out.println("count = " + count);
        System.out.println("onlineUser = " + onlineUser);
        System.out.println("age = " + age);
        System.out.println("contentType = " + contentType);
        System.out.println("name = " + name);
        System.out.println("company = " + company);
        return "user";
    }

@GetMapping("/array")
public String testArray(@RequestParam("array") String[] array) throws Exception {
    System.out.println(Arrays.toString(array));
    return "array";
}

@Data
public class QueryVo {
    private String sortField;
    private User user;
    private Long[] ids;
    private List<User> userList;
    private Map<String, User> userMap;
}

@PostMapping("queryParam")
public String queryParam(QueryVo queryVo) {
    System.out.println(queryVo);
    return "user";
}

@Override
protected void doFilterInternal(
    HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
    throws ServletException, IOException {

    String encoding = getEncoding();
    if (encoding != null) {
        if (isForceRequestEncoding() || request.getCharacterEncoding() == null) {
            request.setCharacterEncoding(encoding);
        }
        if (isForceResponseEncoding()) {
            response.setCharacterEncoding(encoding);
        }
    }
    filterChain.doFilter(request, response);
}

// produces指定了响应的Content-Type
@RequestMapping(value = "getUsers",produces = {"application/json;charset=utf-8"})
@ResponseBody  // 将返回的结果直接写入响应体，不走视图解析器
public String getUsers(){
    List<User> users =  new ArrayList<User>(){{
        add(new User("Tom","2222"));
        add(new User("jerry","333"));
    }};
    return JSONArray.toJSONString(users);
}

@RequestMapping(value = "getUsersList")
@ResponseBody
public List<User> getUsersList(){
    return   new ArrayList<User>(){{
        add(new User("邸智伟","2222"));
        add(new User("刘展鹏","333"));
    }};
}

public class CustomObjectMapper extends ObjectMapper {

    public CustomObjectMapper() {
        super();
        //去掉默认的时间戳格式
        configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
        //设置为东八区
        setTimeZone(TimeZone.getTimeZone("GMT+8"));
        //设置日期转换yyyy-MM-dd HH:mm:ss
        setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));
        // 设置输入:禁止把POJO中值为null的字段映射到json字符串中
        configure(SerializationFeature.WRITE_NULL_MAP_VALUES, false);
        // 空值不序列化
        setSerializationInclusion(JsonInclude.Include.NON_NULL);
        // 反序列化时，属性不存在的兼容处理
        getDeserializationConfig().withoutFeatures(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
        // 序列化枚举是以toString()来输出，默认false，即默认以name()来输出
        configure(SerializationFeature.WRITE_ENUMS_USING_TO_STRING, true);
    }
}

@PostMapping("insertUser")
public String insertUser(@RequestBody User user) {
    System.out.println(user);
    return "user";
}

public class StringToDateConverter implements Converter<String, Date> {
    @Override
    public Date convert(String source) {
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy_MM_dd hh,mm,ss");
        try {
            return simpleDateFormat.parse(source);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        return null;
    }
}

// 对象和json互相转化的过程当中按照此转化方式转哈
@JsonFormat(
            pattern = "yyyy年MM月dd日",
            timezone = "GMT-8"
    )
// 从requestParam中获取参数并且转化
@DateTimeFormat(pattern = "yyyy年MM月dd日")
private Date birthday;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class UserVO {

    @NotNull(message = "用户名不能为空")
    private String username;

    @NotNull(message = "用户名不能为空")
    private String password;

    @Min(value = 0, message = "年龄不能小于{value}")
    @Max(value = 120,message = "年龄不能大于{value}")
    private int age;

    @JsonFormat(
            pattern = "yyyy-MM-dd",
            timezone = "GMT-8"
    )
    @DateTimeFormat(pattern = "yyyy-MM-dd")
    @Past(message = "生日不能大于今天")
    private Date birthday;

    @Pattern(regexp = "^1([358][0-9]|4[579]|66|7[0135678]|9[89])[0-9]{8}$", message = "手机号码不正确")
    private String phone;

    @Email
    private String email;
}

@PostMapping("insert")
public String insert(@Validated UserVO user, BindingResult br) {
    List<ObjectError> allErrors = br.getAllErrors();
    Iterator<ObjectError> iterator = allErrors.iterator();
    // 打印以下错误结果
    while (iterator.hasNext()){
        ObjectError error = iterator.next();
        log.error("user数据校验错误:{}",error.getDefaultMessage());
    }

    if(allErrors.size() > 0){
        return "error";
    }

    System.out.println(user);
    return "user";
}

public class GlobalExceptionResolver implements HandlerExceptionResolver {
    @Override
    public ModelAndView resolveException(HttpServletRequest request,
                                         HttpServletResponse response, Object handler, Exception ex) {
        ModelAndView modelAndView = new ModelAndView();
        modelAndView.addObject("error", ex.getMessage());
        modelAndView.setViewName("error");
        return modelAndView;
    }
}

@Component
public class GlobalExecptionResovler implements HandlerExceptionResolver {}

@Slf4j
@ControllerAdvice
public class GlobalExceptionResolverController  {

    @ExceptionHandler(ArithmeticException.class)
    public String processArithmeticException(ArithmeticException ex){
        log.error("发生了数学类的异常：",ex);
        return "error";
    }

    @ExceptionHandler(BusinessException.class)
    public String processBusinessException(BusinessException ex){
        log.error("发生了业务相关的异常：",ex);
        return "error";
    }

    @ExceptionHandler(Exception.class)
    public String processException(Exception ex){
        log.error("发生了其他的异常：",ex);
        return "error";
    }
}

public class LoginInterceptor implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) {}

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {}
}

/**
 *  登录拦截器
 */
public class LoginInterceptor implements HandlerInterceptor {

    /**
        在执行Controller方法前拦截，判断用户是否已经登录，
        登录了就放行，还没登录就重定向到登录页面
    */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {
        HttpSession session = request.getSession();
        User user = session.getAttribute("user");
        if (user == null){
            //还没登录，重定向到登录页面
            response.sendRedirect("/toLogin");
        }else {
            //已经登录，放行
            return true;
        }
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) {}

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {}
}

@Configuration
@EnableWebMvc
public class MvcConfiguration implements WebMvcConfigurer {

    // 拦截器进行配置
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new LoginInterceptor())
                .addPathPatterns("/**")
                .excludePathPatterns(List.of("/toLogin","/login"))
                .order(1);
    }

    // 资源的配置
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/js/**").addResourceLocations("/static/js/");
        registry.addResourceHandler("/css/**").addResourceLocations("/static/css/");
    }

    // 跨域的全局配置
    @Override
    public void addCorsMappings(CorsRegistry registry) {
        registry.addMapping("/api/**")
                .allowedOrigins("*")
                .allowedMethods("GET","POST","PUT","DELETE")
                .maxAge(3600);
    }

    // 页面跳转的配置
    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
        registry.addViewController("/index").setViewName("index");
    }

}