Spring MVC各组件近距离接触--中--03

// 注意：它可不是Spring3后才推出的  最初就有
public interface Validator {
	// 此clazz是否可以被validate
	boolean supports(Class<?> clazz);
	// 执行校验，错误消息放在Errors 装着
	// 可以参考ValidationUtils这个工具类，它能帮助你很多
	void validate(Object target, Errors errors);
}

@Data
public class Customer {
    private String address;
    private String name;
    private List<ShopCard> shopCard;
}

@Data
public class ShopCard {
    private Integer money;
    @DateTimeFormat(pattern = "yyyy-MM-dd")
    private LocalDate endTime;
}

/**
 * @author 大忽悠
 * @create 2022/7/28 11:49
 */
public class CustomerValidator implements Validator {

    private final ShopCardValidator shopCardValidator=new ShopCardValidator();

    @Override
    public boolean supports(Class<?> clazz) {
        return ClassUtils.isAssignable(clazz,Customer.class);
    }


    @Override
    public void validate(Object target, Errors  errors) {
        Customer customer = (Customer) target;
        ValidationUtils.rejectIfEmpty(errors,"name","name.empty");
        ValidationUtils.rejectIfEmpty(errors,"address","address.empty");

        for (int i = 0; i < customer.getShopCard().size(); i++) {
            errors.pushNestedPath("shopCard["+i+"]");
            ValidationUtils.invokeValidator(shopCardValidator,customer.getShopCard().get(i),errors);
            errors.popNestedPath();
        }
    }


    public static class ShopCardValidator implements Validator{
        @Override
        public boolean supports(Class<?> clazz) {
            return ClassUtils.isAssignable(clazz,ShopCard.class);
        }

        @Override
        public void validate(Object target, Errors errors) {
            ShopCard shopCard = (ShopCard) target;
            if(shopCard.getEndTime().isAfter(LocalDate.now())){
                errors.reject("errorCode.shopCard.is.error");
                errors.rejectValue("endTime","endTime.is.error","购物卡截止时间有误");
            }
            if(shopCard.getMoney()<0){
                errors.rejectValue("money","money.not.negative");
            }
        }
    }
}

    @Test
    public void test() throws BindException {
        HttpServletRequest request = getRequest();
        Customer customer = new Customer();
        ServletRequestDataBinder  requestDataBinder = new ServletRequestDataBinder(customer, "顾客");
        doBind(request, requestDataBinder);
        doValidate(requestDataBinder);
        //判断是否绑定过程是否产生了错误
        requestDataBinder.close();
        System.out.println(customer);
    }

    private void doValidate(ServletRequestDataBinder requestDataBinder) {
        requestDataBinder.addValidators(new CustomerValidator());
        requestDataBinder.validate();
    }

    private void doBind(HttpServletRequest request, ServletRequestDataBinder requestDataBinder) throws BindException {
        //注册相关默认日期类型转换器---包括解析 @DateTimeFormat注解的
        requestDataBinder.setConversionService(new DefaultFormattingConversionService());
        requestDataBinder.bind(request);
    }

    private HttpServletRequest getRequest() {
        //需要添加spring-test依赖支持
        MockHttpServletRequest mockReq = new MockHttpServletRequest();
        mockReq.addParameter("address","翻斗大街--->花园村--->520号");
        mockReq.addParameter("name","胡图图");
        mockReq.addParameter("shopCard[0].money","-1");
        mockReq.addParameter("shopCard[0].endTime","2050-01-02");
        mockReq.addParameter("shopCard[1].money","-2");
        mockReq.addParameter("shopCard[1].endTime","2030-01-02");
        return mockReq;
    }

org.springframework.validation.BindException: org.springframework.validation.BeanPropertyBindingResult: 6 errors
Error in object '顾客': codes [errorCode.shopCard.is.error.顾客,errorCode.shopCard.is.error]; arguments []; default message [null]
Field error in object '顾客' on field 'shopCard[0].endTime': rejected value [2050-01-02]; codes [endTime.is.error.顾客.shopCard[0].endTime,endTime.is.error.顾客.shopCard.endTime,endTime.is.error.shopCard[0].endTime,endTime.is.error.shopCard.endTime,endTime.is.error.endTime,endTime.is.error.java.time.LocalDate,endTime.is.error]; arguments []; default message [购物卡截止时间有误]
Field error in object '顾客' on field 'shopCard[0].money': rejected value [-1]; codes [money.not.negative.顾客.shopCard[0].money,money.not.negative.顾客.shopCard.money,money.not.negative.shopCard[0].money,money.not.negative.shopCard.money,money.not.negative.money,money.not.negative.java.lang.Integer,money.not.negative]; arguments []; default message [null]
Error in object '顾客': codes [errorCode.shopCard.is.error.顾客,errorCode.shopCard.is.error]; arguments []; default message [null]
Field error in object '顾客' on field 'shopCard[1].endTime': rejected value [2030-01-02]; codes [endTime.is.error.顾客.shopCard[1].endTime,endTime.is.error.顾客.shopCard.endTime,endTime.is.error.shopCard[1].endTime,endTime.is.error.shopCard.endTime,endTime.is.error.endTime,endTime.is.error.java.time.LocalDate,endTime.is.error]; arguments []; default message [购物卡截止时间有误]
Field error in object '顾客' on field 'shopCard[1].money': rejected value [-2]; codes [money.not.negative.顾客.shopCard[1].money,money.not.negative.顾客.shopCard.money,money.not.negative.shopCard[1].money,money.not.negative.shopCard.money,money.not.negative.money,money.not.negative.java.lang.Integer,money.not.negative]; arguments []; default message [null]

   //目标对象名和对应class对象，用来反射初始化 
   	public static final String DEFAULT_COMMAND_NAME = "command";

	private String commandName = DEFAULT_COMMAND_NAME;

	private Class commandClass;
  
  //校验器数组
	private Validator[] validators;
 //是否在数据绑定结束后,进行数据校验
	private boolean validateOnBinding = true;
 
 //关于DataBinder一些配置
	private MessageCodesResolver messageCodesResolver;

	private BindingErrorProcessor bindingErrorProcessor;

	private PropertyEditorRegistrar[] propertyEditorRegistrars;

	private WebBindingInitializer webBindingInitializer;

    //同时完成数据绑定和校验 
	protected final ServletRequestDataBinder bindAndValidate(HttpServletRequest request, Object command)
			throws Exception {
        //创建DataBinder
		ServletRequestDataBinder binder = createBinder(request, command);
		//BindException就是一个简单的代理类,所有方法的实现全部由传入的BindingResult完成，只不过该类实现了Exception接口
		BindException errors = new BindException(binder.getBindingResult());
		//是否阻止数据绑定,默认是flase
		if (!suppressBinding(request)) {
		    //进行数据绑定
			binder.bind(request);
			//留给子类的扩展接口
			onBind(request, command, errors);
			//isValidateOnBinding判断是否要在数据绑定结束后进行数据校验，默认为true
			//suppressValidation是否阻止当前的数据校验,默认false
			if (this.validators != null && isValidateOnBinding() && !suppressValidation(request, command, errors)) {    
			   //进行数据校验
				for (int i = 0; i < this.validators.length; i++) {
					ValidationUtils.invokeValidator(this.validators[i], command, errors);
				}
			}
			//扩展接口
			onBindAndValidate(request, command, errors);
		}
		return binder;
	}

	protected ServletRequestDataBinder createBinder(HttpServletRequest request, Object command)
		throws Exception {
       
		ServletRequestDataBinder binder = new ServletRequestDataBinder(command, getCommandName());
		//BaseCommandController内部提供的配置属性，当然要在这里决定是否起作用喽！
		prepareBinder(binder);
		//交给WebBindingInitializer决定，是否要对Binder进行一波配置更改
		initBinder(request, binder);
		return binder;
	}

	protected final void prepareBinder(ServletRequestDataBinder binder) {
		if (useDirectFieldAccess()) {
			binder.initDirectFieldAccess();
		}
		if (this.messageCodesResolver != null) {
			binder.setMessageCodesResolver(this.messageCodesResolver);
		}
		if (this.bindingErrorProcessor != null) {
			binder.setBindingErrorProcessor(this.bindingErrorProcessor);
		}
		if (this.propertyEditorRegistrars != null) {
			for (int i = 0; i < this.propertyEditorRegistrars.length; i++) {
				this.propertyEditorRegistrars[i].registerCustomEditors(binder);
			}
		}
	}
    
    protected void initBinder(HttpServletRequest request, ServletRequestDataBinder binder) throws Exception {
		if (this.webBindingInitializer != null) {
			this.webBindingInitializer.initBinder(binder, new ServletWebRequest(request));
		}
	}

	@Override
	protected ModelAndView handleRequestInternal(HttpServletRequest request, HttpServletResponse response)
			throws Exception {

		//判断当前请求是否是表单处理请求----如果是POST请求，就默认为true
		if (isFormSubmission(request)) {
			// Fetch form object from HTTP session, bind, validate, process submission.
			try {
			//反射获取目标对象
				Object command = getCommand(request);
			//绑定然后进行校验	
				ServletRequestDataBinder binder = bindAndValidate(request, command);
		    //用于存放错误信息		
				BindException errors = new BindException(binder.getBindingResult());
			//处理表单提交---子类实现
				return processFormSubmission(request, response, command, errors);
			}
			catch (HttpSessionRequiredException ex) {
				// Cannot submit a session form if no form object is in the session.
				if (logger.isDebugEnabled()) {
					logger.debug("Invalid submit detected: " + ex.getMessage());
				}
				//如果出现异常,那么进行处理
				//这里是再次尝试去提交一遍表单
				return handleInvalidSubmit(request, response);
			}
		}

		else {
			// New form to show: render form view.
			//渲染表单----最终调用到showForm方法
			return showNewForm(request, response);
		}
	}

	@Override
	protected ModelAndView handleRequestInternal(HttpServletRequest request, HttpServletResponse response)
			throws Exception {
        //反射实例化对象
		Object command = getCommand(request);
		//数据绑定和验证
		ServletRequestDataBinder binder = bindAndValidate(request, command);
		//错误记录
		BindException errors = new BindException(binder.getBindingResult());
		//留给子类实现的抽象方法
		return handle(request, response, command, errors);
	}
    
    //抽象方法
	protected abstract ModelAndView handle(
			HttpServletRequest request, HttpServletResponse response, Object command, BindException errors)throws Exception;

public class ParameterizableViewController extends AbstractController {

	private String viewName;

	public void setViewName(String viewName) {
		this.viewName = viewName;
	}

	public String getViewName() {
		return this.viewName;
	}


	@Override
	protected ModelAndView handleRequestInternal(HttpServletRequest request, HttpServletResponse response)
			throws Exception {
		return new ModelAndView(getViewName(), RequestContextUtils.getInputFlashMap(request));
	}

}

    <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/"/>
        <property name="suffix" value=".jsp"/>
    </bean>


    <bean id="handlerMapping" class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">
        <property name="mappings">
            <props>
                <prop key="/hello/**">parameterizableViewController</prop>
            </props>
        </property>
    </bean>

    <bean id="parameterizableViewController" class="org.springframework.web.servlet.mvc.ParameterizableViewController">
        <property name="viewName" value="jsp/hello"></property>
    </bean>

	@Override
	protected ModelAndView handleRequestInternal(HttpServletRequest request, HttpServletResponse response) {
	    //确定当前请求的访问路径,这里路径解析涉及到是保留context路径和servlet拦截的full path路径，还是去掉的问题，因此比较麻烦
	    //但是对于spring mvc提供的DispathcerServlet来说,默认拦截路径为/,我们这里在web.xml中配置的也是'/'
	    //并且contextPath也是'/'
	    //因此不需要操心路径的问题
		String lookupPath = getUrlPathHelper().getLookupPathForRequest(request);
		//如何获取到viewName是由子类来实现的,这也是核心逻辑
		String viewName = getViewNameForRequest(request);
		if (logger.isDebugEnabled()) {
			logger.debug("Returning view name '" + viewName + "' for lookup path [" + lookupPath + "]");
		}
		return new ModelAndView(viewName, RequestContextUtils.getInputFlashMap(request));
	}

	@Override
	protected String getViewNameForRequest(HttpServletRequest request) {
		//抽取出uri请求路径
		//获取AbstractUrlHandlerMapping中exposePathWithinMapping缓存的请求路径
		//SimpleUrlHandlerMapping模糊匹配的路径为/hello/** ,而我们访问的路径为/hello/hello
		//这里抽取拿到的就是去掉匹配前缀剩余部分,即hello
		String uri = extractOperableUrl(request);
		//通过请求路径,拿到viewName
		return getViewNameForUrlPath(uri);
	}
    
	private final Map<String, String> viewNameCache = new ConcurrentHashMap<String, String>(256);
    //会缓存请求路径对应的viewName
    protected String getViewNameForUrlPath(String uri) {
		String viewName = this.viewNameCache.get(uri);
		if (viewName == null) {
			viewName = extractViewNameFromUrlPath(uri);
			viewName = postProcessViewName(viewName);
			this.viewNameCache.put(uri, viewName);
		}
		return viewName;
	}
    
    //如果uri是 "/index.html" ，那么抽取后返回的就是index,俗称掐头去尾 
	protected String extractViewNameFromUrlPath(String uri) {
		int start = (uri.charAt(0) == '/' ? 1 : 0);
		int lastIndex = uri.lastIndexOf(".");
		int end = (lastIndex < 0 ? uri.length() : lastIndex);
		return uri.substring(start, end);
	}

    private String prefix = "";
	private String suffix = "";
    //后处理viewName,说白了就是加上给上面得到的viewName,加上前后缀
	protected String postProcessViewName(String viewName) {
		return getPrefix() + viewName + getSuffix();
	}

"/index" -> "index"
"/index.html" -> "index"
"/index.html" + prefix "pre_" and suffix "_suf" -> "pre_index_suf"
"/products/view.html" -> "products/view"

    <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/"/>
        <property name="suffix" value=".jsp"/>
    </bean>


    <bean id="handlerMapping" class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">
        <property name="mappings">
            <props>
                <prop key="/hello/**">urlfilenameviewcontroller</prop>
            </props>
        </property>
    </bean>

    <bean id="urlfilenameviewcontroller" class="org.springframework.web.servlet.mvc.UrlFilenameViewController">
        <property name="prefix" value="jsp/"/>
    </bean>