SPRING IN ACTION 第4版笔记-第六章RENDERING WEB VIEWS-002- Spring的JSP标签之form标签(<sf:input><sf:errors><sf:form>)

一、

Spring offers two JSP tag libraries to help define the view of your Spring MVC web views.

One tag library renders HTML form tags that are bound to a model attribute.

The other has a hodgepodge of utility tags that come in handy from time to time.

1.Spring支持的form标签

2.一般用法

<%@ taglib uri="http://www.springframework.org/tags/form" prefix="sf" %>
<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>

path是和model里的对象的属性对应，commandName是和model的key对应，这里设定了commandName="spitter"，则要保证每个返回到这个view的handler的model都要有值为"spitter"的key,所以showRegistrationForm()要修改，返回一个空对象，否则会报java.lang.IllegalStateException: Neither BindingResult nor plain target object for bean name 'spitter' available as request attribute。

RequestMapping(value = "/register", method = GET)
public String showRegistrationForm(Model model) {
    model.addAttribute(new Spitter());
    return "registerForm";
}

3.Spring form标签还支持html5,如可以指定data、range、email

<sf:input path="email" type="email" />

4.显示错误

<sf:form method="POST" commandName="spitter">
    First Name:
    <sf:input path="firstName" />
    <sf:errors path="firstName" />
    <br/> ...
</sf:form>

若验证有错，会解析类似如下：

First Name: <input id="firstName" name="firstName" type="text" value="J"/>
            <span id="firstName.errors">size must be between 2 and 30</span>

5.可以加css

<sf:form method="POST" commandName="spitter">
    First Name:
    <sf:input path="firstName" />
    <sf:errors path="firstName" cssClass="error" />
    <br/> ...
</sf:form>

span.error {color: red;}

6.错误集中显示

<sf:form method="POST" commandName="spitter">
    <sf:errors path="*" element="div" cssClass="errors" /> 
    ...
</sf:form>

div.errors {
    background - color: #ffcccc;
    border: 2 px solid red;
}

7.哪个字段有错就红色显示该字段

<sf:form method="POST" commandName="spitter">
    <sf:label path="firstName" cssErrorClass="error">First Name</sf:label>:
    <sf:input path="firstName" cssErrorClass="error" />
    <br/> ...
</sf:form>

8.要实体类中写验证规则

package spittr;

import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;

import org.apache.commons.lang3.builder.EqualsBuilder;
import org.apache.commons.lang3.builder.HashCodeBuilder;
import org.hibernate.validator.constraints.Email;

public class Spitter {

  private Long id;
  
  @NotNull
  @Size(min=5, max=16, message="{username.size}")
  private String username;

  @NotNull
  @Size(min=5, max=25, message="{password.size}")
  private String password;
  
  @NotNull
  @Size(min=2, max=30, message="{firstName.size}")
  private String firstName;

  @NotNull
  @Size(min=2, max=30, message="{lastName.size}")
  private String lastName;
  
  @NotNull
  @Email
  private String email;

  @Override
  public boolean equals(Object that) {
    return EqualsBuilder.reflectionEquals(this, that, "firstName", "lastName", "username", "password", "email");
  }
  
  @Override
  public int hashCode() {
    return HashCodeBuilder.reflectionHashCode(this, "firstName", "lastName", "username", "password", "email");
  }

}

9.验证信息的资源文件，可定不同的语言版本支持国际化(不知道什么时候加载的

(1)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.

(2)ValidationMessages_es.properties 西班牙

firstName.size=Nombre debe ser entre {min} y {max} caracteres largo.
lastName.size=El apellido debe ser entre {min} y {max} caracteres largo.
username.size=Nombre de usuario debe ser entre {min} y {max} caracteres largo.
password.size=Contraseña debe estar entre {min} y {max} caracteres largo.
email.valid=La dirección de email no es válida

(3)webconfig.java

package spittr.web;

import org.springframework.context.MessageSource;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.support.ReloadableResourceBundleMessageSource;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.DefaultServletHandlerConfigurer;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import org.springframework.web.servlet.view.InternalResourceViewResolver;

@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;
  }
  
  @Override
  public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
    configurer.enable();
  }
  
  @Override
  public void addResourceHandlers(ResourceHandlerRegistry registry) {
    // TODO Auto-generated method stub
    super.addResourceHandlers(registry);
  }
  
  @Bean
  public MessageSource messageSource() {
    ReloadableResourceBundleMessageSource messageSource = 
        new ReloadableResourceBundleMessageSource();
    //messageSource.setBasename("file:///Users/habuma/messages");
    //messageSource.setBasename("messages");
    messageSource.setBasename("classpath:messages");
    messageSource.setCacheSeconds(10);
    return messageSource;
  }
 
}

10.view

<%@ 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" >
      <sf:errors path="*" element="div" cssClass="errors" />
      <sf:label path="firstName" 
          cssErrorClass="error">First Name</sf:label>: 
        <sf:input path="firstName" cssErrorClass="error" /><br/>
      <sf:label path="lastName" 
          cssErrorClass="error">Last Name</sf:label>: 
        <sf:input path="lastName" cssErrorClass="error" /><br/>
      <sf:label path="email" 
          cssErrorClass="error">Email</sf:label>: 
        <sf:input path="email" cssErrorClass="error" /><br/>
      <sf:label path="username" 
          cssErrorClass="error">Username</sf:label>: 
        <sf:input path="username" cssErrorClass="error" /><br/>
      <sf:label path="password" 
          cssErrorClass="error">Password</sf:label>: 
        <sf:password path="password" cssErrorClass="error" /><br/>
      <input type="submit" value="Register" />
    </sf:form>
  </body>
</html>

11.controller

package spittr.web;

import static org.springframework.web.bind.annotation.RequestMethod.*;

import javax.validation.Valid;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.validation.Errors;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;

import spittr.Spitter;
import spittr.data.SpitterRepository;

@Controller
@RequestMapping("/spitter")
public class SpitterController {

  private SpitterRepository spitterRepository;

  @Autowired
  public SpitterController(SpitterRepository spitterRepository) {
    this.spitterRepository = spitterRepository;
  }
  
//  @ModelAttribute
//  public Spitter spitter() {
//    return new Spitter();
//  }
  
  @RequestMapping(value="/register", method=GET)
  public String showRegistrationForm(Model model) {
    model.addAttribute(new Spitter());
    return "registerForm";
  }
  
  @RequestMapping(value="/register", method=POST)
  public String processRegistration(
      @Valid Spitter spitter, 
      Errors errors) {
    if (errors.hasErrors()) {
      return "registerForm";
    }
    
    spitterRepository.save(spitter);
    return "redirect:/spitter/" + spitter.getUsername();
  }
  
  @RequestMapping(value="/{username}", method=GET)
  public String showSpitterProfile(@PathVariable String username, Model model) {
    Spitter spitter = spitterRepository.findByUsername(username);
    model.addAttribute(spitter);
    return "profile";
  }
  
}