表单标签库
表单标签库中包含了可以用在jsp页面中渲染HTML元素的标签。为了使用这些标签,必须在jsp页面中的开头出声明taglib指令。
<%@ taglib prefix="form" uri="http://springframework.org/tags/form" %>
在表单标签库中的标签
标签 | 描述 |
---|---|
form | 渲染表单元素 |
input | 渲染 <input type="text"/> 元素 |
password | 渲染 <input type="password"/> 元素 |
hidden | 渲染<input ttpe="hidden"/> 元素 |
textarea | 渲染textarea元素 |
checkbox | 渲染一个<input type="checkbox"/>元素 |
checkboxes | 渲染多个<input type="checkbox"/> 元素 |
radiobutton | 渲染一个<input type="redioButton"/> 元素 |
radiobuttons | 渲染多个<input type="redioButton"/> 元素 |
select | 渲染一个选择元素 |
option | 渲染一个可选元素 |
options | 渲染一个可选元素列表 |
errors | 在span元素中渲染字段错误 |
表单标签用于渲染HTML表单。表单标签必须利用渲染表单输入字段的其他任意标签。
<form:form commandName="book" action="book_save" method="post">
<!-- commandName属性或许是最重要的属性,因为它定义了模型(Model)属性的名称,其中包含了一个backing object,其属性将用于填充所生成的表单。如果该属性存在,则必须再返回包含该视图的请求处理方法中添加相应的模型属性 -->
</form:form>
表单标签的属性
属性 | 描述 |
---|---|
acceptCharset | 定义服务器接受的字符编码列表 |
commandName | 暴露表单对象之模型属性的名称,默认为command |
cssClass | 定义要应用到被渲染form元素的CSS类 |
cssStyle | 定义要应用到被渲染form元素的CSS样式 |
htmlEscape | 接受true或者false, 表示被渲染的值是否应该进行HTML转义 |
modeAttribute | 暴露form backing object 的模型属性名称,默认为commend |
展示代码部分
@RequestMapping(value="/页面路径")
public String inputBook(Model model){
...
model.addAttribute("book", new Book());
return "要跳转的页面";
}
在代码当中此处用book属性创建了一个Book对象,并添加到Model.如果没有Model属性,跳转的页面就会抛出异常,因为表单标签无法找到在其commandName属性中指定的dorm backing object.
input标签
input标签渲染<input type="text"/>
元素。这个标签最重要的属性是path,它将这个输入字段绑定到form backing object的一个属性。例如,若随附<form/>
标签的commandName属性值为book,并且input属性值为isbn,那么,input标签将被绑定到Book对象的isbn属性。
input标签的属性
属性 | 描述 |
---|---|
cssClass | 定义要应用到被渲染input元素的css类 |
cssStyle | 定义要应用到被渲染input元素的css样式 |
cssErrorClass | 定义要应用到被渲染input元素的css类,如果bound属性中包含错误,则覆盖cssClass属性值 |
htmlEscape | 接受true或者false,表示十分应该对被渲染的值进行HTML转义 |
path | 要绑定的属性路径 |
举个例子
<form:input id="isbn" path="isbn" cssErrorClass="errorBox"/>
他将会被渲染成下面的<input/>
元素:
<input type="text" id="isbn" name="isbn"/>
cssErrorClass属性不起作用,除非isbn属性中输入验证错误,并且采用同一个表单重行显示用户输入,在这种情况下,input标签就会被渲染成下面这个input元素。
<input type="text" id="isbn" name="isbn" class="errorBox"/>
input标签也可以绑定到嵌套对象的属性。例如,下列的input标签绑定到form backing object的category属性的id属性。
<form:input path="categery.id"/>
剩下的标签就不一一介绍,如果读者感兴趣看文档会更详细。
一个小的例子
domain里面的bean
package domain;
import java.io.Serializable;
public class Book implements Serializable{
private static final long serialVersionUID = 7461688389112847430L;
private long id;
private String isbn;
private String title;
private Category category;
private String author;
public Book(){}//无参的构造方法
//有参的构造方法
public Book(long id, String isbn, String title, Category catgory, String author){
this.id = id;
this.isbn = isbn;
this.title = title;
this.category = catgory;
this.author = author;
}
//get and set method
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public String getIsbn() {
return isbn;
}
public void setIsbn(String isbn) {
this.isbn = isbn;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public Category getCategory() {
return category;
}
public void setCategory(Category category) {
this.category = category;
}
public String getAuthor() {
return author;
}
public void setAuthor(String author) {
this.author = author;
}
}
package domain;
import java.io.Serializable;
public class Category implements Serializable{
private static final long serialVersionUID = -6019865946011659102L;
private int id;
private String name;
public Category(){}//无参
//Constructor with arguments
public Category(int id, String name) {
this.id = id;
this.name = name;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
//get and set method
}
控制器的相关类
package controller;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import domain.Book;
import domain.Category;
import java.util.List;
import service.BookService;
@Controller
public class BookController {
@Autowired
private BookService bookService;
private static final Log logger = LogFactory.getLog(BookController.class);
@RequestMapping(value="/book_input")
public String inputBook(Model model){
List<Category> category = bookService.getAllcategories();
model.addAttribute("book", new Book());
model.addAttribute("category", category);
return "BookAddForm";
}
@RequestMapping(value="/book_edit/{id}")
public String editBook(Model model, @PathVariable long id){
List<Category> category = bookService.getAllcategories();
model.addAttribute("category", category);
Book book = bookService.get(id);
model.addAttribute("book", book);
return "BookEditForm";
}
@RequestMapping(value="/book_save")
public String saveBook(@ModelAttribute Book book){
Category category = bookService.getCategory(book.getCategory().getId());
book.setCategory(category);
bookService.save(book);
return "redirect:/book_list";
}
@RequestMapping(value="/book_update")
public String updateBook(@ModelAttribute Book book){
Category category = bookService.getCategory(book.getCategory().getId());
book.setCategory(category);
bookService.update(book);
return "redirect:/book_list";
}
@RequestMapping(value="/book_list")
public String listBooks(Model model){
logger.info("book_list");
List<Book> books = bookService.getAllBooks();
model.addAttribute("books", books);
// System.out.println("进入");
return "BookList";
}
}
实现的方法以及接口servlet
package service;
import java.util.List;
import domain.Book;
import domain.Category;
public interface BookService {
List<Category> getAllcategories();
Category getCategory(int id);
List<Book> getAllBooks();
Book save(Book book);
Book update(Book book);
Book get(long id);
long getNextId();
}
package service;
import java.util.ArrayList;
import java.util.List;
import org.springframework.stereotype.Service;
import domain.Book;
import domain.Category;
@Service
public class BookServiceImpl implements BookService{
/*
* this implementation is not thread-safe
*/
private List<Category> category;
private List<Book> books;
public BookServiceImpl() {
category = new ArrayList<>();
Category category1 = new Category(1, "Computing");
Category category2 = new Category(2, "Travel");
Category category3 = new Category(3, "Health");
category.add(category1);
category.add(category2);
category.add(category3);
books = new ArrayList<>();
books.add(new Book(1L, "9780980839623", "servlet & jsp: a tutorial", category1, "Budi Kurniawan"));
books.add(new Book(2L, "9780980839620", "c# A Beginner's Tutorial", category1, "Jayden Ky"));
}
@Override
public List<Category> getAllcategories() {
return category;
}
@Override
public Category getCategory(int id) {
for(Category category1 : category)
if(id == category1.getId())
return category1;
return null;
}
@Override
public List<Book> getAllBooks() {
return books;
}
//执行添加操作
@Override
public Book save(Book book) {
book.setId(getNextId());
books.add(book);
return book;
}
//执行更新操作
@Override
public Book update(Book book) {
int bookCount = books.size();
for(int i = 0; i < bookCount; i++){
Book savedBook = books.get(i);
if(savedBook.getId() == book.getId()){
books.set(i, book);
return book;
}
}
return book;
}
//获取书籍的内容
@Override
public Book get(long id) {
for(Book book : books){
if(id == book.getId())
return book;
}
return null;
}
@Override
public long getNextId() {
//needs to be locked
long id = 0L;
for(Book book : books){
long bookId = book.getId();
if(bookId > id)
id = bookId;
}
return id + 1;
}
}
jsp片段
<!--BookAddForm.jsp-->
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Add Book Form</title>
<style type="text.css">@import url("<c:url value="/css/main.css"/>");</style>
</head>
<body>
<!-- 添加书籍的信息 -->
<div id="global">
<form:form commandName="book" action="book_save" method="post">
<fieldset>
<legend>Add a book</legend>
<p>
<label for="category">Category:</label>
<form:select id="category" path="category.id" items="${category}"
itemLabel="name" itemValue="id"/>
</p>
<p>
<label for="title">Title:</label>
<form:input id="title" path="title"/>
</p>
<p>
<label for="author">Author:</label>
<form:input path="author" id="author"/>
</p>
<p>
<label for="isbn">ISBN:</label>
<form:input path="isbn" id="isbn"/>
</p>
<p id="buttons">
<input id="reset" type="reset" tabindex="4" value="reset"/>
<input id="submit" type="submit" tabindex="5" value="Add Book"/>
</p>
</fieldset>
</form:form>
</div>
</body>
</html>
<!-- BookEditForm.jsp -->
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Edit Book Form</title>
<style type="text.css">@import url("<c:url value="/css/main.css"/>");</style>
</head>
<body>
<!-- 执行更新操作的页面 -->
<div id="global">
<form:form commandName="book" action="book_update" method="post">
<fieldset>
<legend>Edit Book Form</legend>
<form:hidden path="id"/>
<p>
<label for="category">Category:</label>
<form:select id="category" path="category.id" items="${category}"
itemLabel="name" itemValue="id"/>
</p>
<p>
<label for="title">Title:</label>
<form:input id="title" path="title"/>
</p>
<p>
<label for="author">Author:</label>
<form:input path="author" id="author"/>
</p>
<p>
<label for="isbn">ISBN:</label>
<form:input path="isbn" id="isbn"/>
</p>
<p id="buttons">
<input id="reset" type="reset" tabindex="4" value="reset"/>
<input id="submit" type="submit" tabindex="5" value="Update Book">
</p>
</fieldset>
</form:form>
</div>
</body>
</html>
<!-- BookList.jsp -->
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Book List</title>
<style type="text.css">@import url("<c:url value="/css/main.css"/>");</style>
</head>
<body>
<div id="global">
<h1>Book List</h1>
<a href="<c:url value="/book_input"/>">Add Book</a>
<table>
<tr>
<th>Category</th>
<th>Title</th>
<th>ISBN</th>
<th>Author</th>
<th> </th>
</tr>
<c:forEach items="${books }" var="book">
<tr>
<td>${book.category.name}</td>
<td>${book.title }</td>
<td>${book.isbn }</td>
<td>${book.author }</td>
<td><a href="book_edit/${book.id}">Edit</a></td>
</tr>
</c:forEach>
</table>
</div>
</body>
</html>
xml的基本配置
<!--web.xml-->
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<servlet>
<servlet-name>spring</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/config/spring-config.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>spring</servlet-name>
<!-- map all requests to the DispatcherServlet -->
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>
<!-- spring-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:p="http://www.springframework.org/schema/p"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd
">
<context:component-scan base-package="controller"></context:component-scan>
<context:component-scan base-package="service"></context:component-scan>
<mvc:annotation-driven/>
<mvc:resources mapping="/css/**" location="/css/"></mvc:resources>
<mvc:resources location="/" mapping="/*.html"></mvc:resources>
<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/jsp/"/>
<property name="suffix" value=".jsp"></property>
</bean>
</beans>