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通常将JSP文件放在 /WEB-INF目录下，防止对它的直接访问
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InternalResourceViewResolver是JSP的视图解析器，它遵循一种约定，会在视图名上添加前缀和后缀，进而定位JSP文件的位置
(1) JavaConfig
@Configuration @EnableWebMvc @ComponentScan("spittr.web") public class WebConfig extends WebMvcConfigurerAdapter { @Bean public ViewResolver viewResolver() { InternalResourceViewResolver resolver = new InternalResourceViewResolver(); resolver.setPrefix("/WEB-INF/views/"); resolver.setSuffix(".jsp"); return resolver; } ... }(2) 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:p="http://www.springframework.org/schema/p" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd"> <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver" p:prefix="/WEB-INF/views/" p:suffix=".jsp"/> ... </beans> -
(1) 如果JSP文件使用JSTL处理格式化和信息的话，应该将视图解析为 JstlView。这时需要设置InternalResourceViewResolver的viewClass属性
(2) Java Config
@Configuration @EnableWebMvc @ComponentScan("spittr.web") public class WebConfig extends WebMvcConfigurerAdapter { @Bean public ViewResolver viewResolver() { InternalResourceViewResolver resolver = new InternalResourceViewResolver(); resolver.setPrefix("/WEB-INF/views/"); resolver.setSuffix(".jsp"); resolver.setViewClass(org.springframework.web.servlet.view.JstlView.class); return resolver; } ... }(3) 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:p="http://www.springframework.org/schema/p" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd"> <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver" p:prefix="/WEB-INF/views/" p:suffix=".jsp" p:viewClass="org.springframework.web.servlet.view.JstlView.class"/> ... </beans> -
使用Spring的JSP库(一):绑定model中的某个属性
(1) Spring的表单绑定JSP库包含14个标签。与原生html标签的区别在于它们可以绑定模型中的一个对象，根据模型中的对象填充值
(2) 使用前要进行声明
<%@ taglib uri="http://www.springframework.org/tags/form" prefix="sf" %>(3) 14个标签
<sf:input> <sf:errors> ...(4) 示例
SpitterController.java
@Controller @RequestMapping("/spitter") public class SpitterController { ... @RequestMapping(value = "/register", method = GET) public String showRegistrationForm(Model model) { model.addAttribute("spitter", new Spitter()); return "registerForm"; } ... }registerForm.jsp
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %> <%@ taglib uri="http://www.springframework.org/tags/form" prefix="sf" %> <%@ page session="false" %> <html> <head> <title>Spitter</title> <link rel="stylesheet" type="text/css" href="<c:url value="/resources/style.css" />"> </head> <body> <h1>Register</h1> <sf:form method="POST" commandName="spitter"> First Name:<sf:input path="firstName"/><br/> Last Name:<sf:input path="lastName"/><br/> Email:<sf:input path="email"/><br/> Username:<sf:input path="username"/><br/> Password:<sf:password path="password"/><br/> <input type="submit" value="Register"/> </sf:form> </body> </html>(5) <form>标签的commandName属性用来绑定某个model,这需要在Controller中添加这个对应名称的model，否则会报错(这里model的名称为"spitter")
(6) <input>标签中的path属性用于设置原生html中value的值，例如<sf:input path="firstName"/>代表这个input的值设定为 spitter.firstName
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展现错误
(1) 使用 <sf:errors>
示例
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %> <%@ taglib uri="http://www.springframework.org/tags/form" prefix="sf" %> <%@ page session="false" %> <html> <head> <title>Spitter</title> <link rel="stylesheet" type="text/css" href="<c:url value="/resources/style.css" />"> </head> <body> <h1>Register</h1> <sf:form method="POST" commandName="spitter" action="/spitter/register"> <sf:label path="firstName" cssErrorClass="error">First Name</sf:label>: <sf:input path="firstName" cssErrorClass="error"/> <sf:errors path="firstName" element="span" cssClass="error"/> <br/> <sf:label path="lastName" cssErrorClass="error">Last Name</sf:label>: <sf:input path="lastName" cssErrorClass="error"/> <sf:errors path="lastName" element="span" cssClass="error"/> <br/> <sf:label path="email" cssErrorClass="error">Email</sf:label>: <sf:input path="email" cssErrorClass="error"/> <sf:errors path="email" element="span" cssClass="error"/> <br/> <sf:label path="username" cssErrorClass="error">Username</sf:label>: <sf:input path="username" cssErrorClass="error"/> <sf:errors path="username" element="span" cssClass="error"/> <br/> <sf:label path="password" cssErrorClass="error">Password</sf:label>: <sf:password path="password" cssErrorClass="error"/> <sf:errors path="password" element="span" cssClass="error"/> <br/> <input type="submit" value="Register"/> </sf:form> </body> </html><sf:errors>的path属性会绑定model的某个字段，以<sf:errors path="firstName" element="span" cssClass="error"/>为例，它会绑定 spitter.firstName这个字段。如果这个字段有问题，那么则显示错误；否则，不渲染任何内容。
<sf:errors>的element属性用于确定错误的渲染类型，span代表html中的<span>用于渲染一行;div代表<div>，代表一个块。
cssClass指定了出现错误时的显示方式，对应的css文件中会有 span.error指定错误时的样式
style.css
... span.error { color: red; } ...(2) 何时产生错误与产生何种错误信息都在模型对应的类中决定
示例
public class Spitter { ... @NotNull(message = "{username.size}") @Size(min = 5, max = 16, message = "{username.size}") private String username; @NotNull(message = "{password.size}") @Size(min = 5, max = 25, message = "{password.size}") private String password; @NotNull(message = "{firstName.size}") @Size(min = 2, max = 30, message = "{firstName.size}") private String firstName; @NotNull(message = "{lastName.size}") @Size(min = 2, max = 30, message = "{lastName.size}") private String lastName; @NotNull @Email(message = "{email.valid}") @Size(min = 3, message = "{email.valid}") private String email; ... }当不满足注解中的要求时，会产生错误；错误的信息由每个注解的message属性指定(添加多重校验注解时，每个注解可以对应不同的message)；
当message属性的内容是"xxx"时，则直接错误信息显示为xxx；当message属性的内容是"{xxx}"时，则错误信息从ValidationMessages.properties属性文件中读取;
ValidationMessages.properties必须叫这个名字，且必须放在根类路径下(即src/main/resources/ValidationMessages.properties);在属性文件中定义message中各种对应的参数
示例 ValidationMessages.properties
firstName.size=First name must be between {min} and {max} characters long. lastName.size=Last name must be between {min} and {max} characters long. username.size=Username must be between {min} and {max} characters long. password.size=Password must be between {min} and {max} characters long. email.valid=The email address must be valid.属性文件也可以有占位符{},{min}代表从校验注解上读取min属性的值
(3) <sf:errors>用来显示额外的错误信息，<sf:input>,<sf:label>同样可以指定发生错误时的显示样式，通过设置 cssError属性
示例
registerForm.jsp
... <sf:label path="email" cssErrorClass="error">Email</sf:label>: <sf:input path="email" cssErrorClass="error"/> ...style.css
... label.error { color: red; } input.error { background-color: #ffcccc; } ... -
使用Spring的JSP库(二):Spring的通用标签库
(1) 使用前要添加声明
<%@ taglib uri="http://www.springframework.org/tags" prefix="s" %>(2) 常用的有10个标签 P180
(3) 代替硬编码 -- <s:message>
将信息放在属性文件里，使用时只需引用属性文件中的值即可
示例
home.jsp
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %> <%@ taglib uri="http://www.springframework.org/tags" prefix="s" %> <%@ page session="false" %> <html> ... <body> <h1><s:message code="spitter.welcome"/></h1> ... </body> </html>messages.properties
spitter.welcome=Welcome to Spitter!为了可以使用属性文件，需要配置信息源，即在JavaConfig文件中添加信息源的Bean
WebConfig.java
@Configuration @EnableWebMvc @ComponentScan("spittr.web") public class WebConfig extends WebMvcConfigurerAdapter { .... @Bean public MessageSource messageSource() { // Method 1 ReloadableResourceBundleMessageSource messageSource = new ReloadableResourceBundleMessageSource(); messageSource.setBasename("/WEB-INF/messages"); messageSource.setCacheSeconds(10); return messageSource; // Method 2 /*ResourceBundleMessageSource messageSource = new ResourceBundleMessageSource(); messageSource.setBasename("messages"); messageSource.setCacheSeconds(10); return messageSource;*/ } }常用的信息源类有两种，一种是ReloadableResourceBundleMessageSource，它从 src/main/webapp开始查找（即web应用的根路径）；另一种是ResourceBundleMessageSource，它从src/main开始查找(即根类路径)
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