Spring如何知道要返回哪个视图?
我是SpringMVC的新手,我不明白Spring如何知道它必须返回priceincrease.jsp,如果它没有映射到控制器中的话 另一件我不明白的事情是spring auto是如何完成表单操作的 我的控制器是:Spring如何知道要返回哪个视图?,spring,spring-mvc,Spring,Spring Mvc,我是SpringMVC的新手,我不明白Spring如何知道它必须返回priceincrease.jsp,如果它没有映射到控制器中的话 另一件我不明白的事情是spring auto是如何完成表单操作的 我的控制器是: @Controller @RequestMapping(value="/priceincrease.html") public class PriceIncreaseFormController { /** Logger for this class and subclas
@Controller
@RequestMapping(value="/priceincrease.html")
public class PriceIncreaseFormController {
/** Logger for this class and subclasses */
protected final Log logger = LogFactory.getLog(getClass());
@Autowired
private ProductManager productManager;
@RequestMapping(method = RequestMethod.POST)
public String onSubmit(@Valid PriceIncrease priceIncrease, BindingResult result)
{
if (result.hasErrors()) {
return "priceincrease";
}
int increase = priceIncrease.getPercentage();
logger.info("Increasing prices by " + increase + "%.");
productManager.increasePrice(increase);
return "redirect:/hello.html";
}
@RequestMapping(method = RequestMethod.GET)
protected PriceIncrease formBackingObject(HttpServletRequest request) throws ServletException {
PriceIncrease priceIncrease = new PriceIncrease();
priceIncrease.setPercentage(15);
return priceIncrease;
}
public void setProductManager(ProductManager productManager) {
this.productManager = productManager;
}
public ProductManager getProductManager() {
return productManager;
}
}
这是控制器返回的jsp
<%@ include file="/WEB-INF/views/include.jsp" %>
<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>
<html>
<head>
<title><fmt:message key="title"/></title>
<style>
.error { color: red; }
</style>
</head>
<body>
<h1><fmt:message key="priceincrease.heading"/></h1>
<form:form method="post" commandName="priceIncrease">
<table width="95%" bgcolor="f8f8ff" border="0" cellspacing="0" cellpadding="5">
<tr>
<td align="right" width="20%">Increase (%):</td>
<td width="20%">
<form:input path="percentage"/>
</td>
<td width="60%">
<form:errors path="percentage" cssClass="error"/>
</td>
</tr>
</table>
<br>
<input type="submit" value="Execute">
</form:form>
<a href="<c:url value="hello.html"/>">Home</a>
</body>
</html>
.错误{颜色:红色;}
增幅(%):
更新:
这是我的app-config.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc.xsd">
<bean id="productManager" class="com.mycompany.springapp.service.SimpleProductManager">
<property name="products">
<list>
<ref bean="product1"/>
<ref bean="product2"/>
<ref bean="product3"/>
</list>
</property>
</bean>
<bean id="product1" class="com.mycompany.springapp.domain.Product">
<property name="description" value="Lamp"/>
<property name="price" value="5.75"/>
</bean>
<bean id="product2" class="com.mycompany.springapp.domain.Product">
<property name="description" value="Table"/>
<property name="price" value="75.25"/>
</bean>
<bean id="product3" class="com.mycompany.springapp.domain.Product">
<property name="description" value="Chair"/>
<property name="price" value="22.79"/>
</bean>
<bean id="messageSource" class="org.springframework.context.support.ResourceBundleMessageSource">
<property name="basename" value="messages"/>
</bean>
<!-- Scans the classpath of this application for @Components to deploy as beans -->
<context:component-scan base-package="com.mycompany.springapp.web" />
<!-- Configures the @Controller programming model -->
<mvc:annotation-driven/>
<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="viewClass" value="org.springframework.web.servlet.view.JstlView"></property>
<property name="prefix" value="/WEB-INF/views/"></property>
<property name="suffix" value=".jsp"></property>
</bean>
</beans>
初始化
DispatcherServlet
时,它将在其应用程序上下文中查找ViewResolver
bean。你只注册了一个
<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="viewClass" value="org.springframework.web.servlet.view.JstlView"></property>
<property name="prefix" value="/WEB-INF/views/"></property>
<property name="suffix" value=".jsp"></property>
</bean>
当处理程序方法返回时,Spring会查看返回值(和处理程序)以确定要执行的操作。在您的情况下,即返回的字符串
值,它将使用ViewNameMethodReturnValueHandler
,这表示返回的字符串
值将用作视图名称
完成后,DispatcherServlet
将通过viewsolver
bean循环检查视图名称是否可以解析为view
对象。如果可以,它将使用该视图,如果不能,它将尝试下一个视图。如果无法解析视图名称,它将失败 我一直在做一些研究,我找到了两个问题之一的答案:
Spring如何知道要返回哪个视图
Spring框架参考文档-17.13.3视图-RequestToViewNameTranslator
SpringServlet.xml中有什么?通常,那里的映射告诉jsp
文件的根,要使用的jsp
与控制器上的@RequestMapping
具有相同的路径和名称。我已经添加了您要求的xml。您能告诉我spring是如何知道它必须返回priceincrease.jsp而不是其他jsp的吗?好的,我理解,但是formBackingObject方法返回的是priceincrease对象而不是字符串,spring是如何将这个对象解析为priceincrease.jsp的?它使用PriceIncrease类名吗?@Martin有一个不同的HandlerMethodReturnValueHandler
来处理这个问题。它被称为ModelAttributeMethodProcessor
,它根据您返回的对象的类型名称确定视图名称。