视图控制层代码demo如下：
@Controller
@RequestMapping("/")
public class MessageController {
private final MessageRepository messageRepository;
@Autowired
public MessageController(MessageRepository messageRepository) {
this.messageRepository = messageRepository;
}
@RequestMapping
public ModelAndView list() {
Iterable<Message> messages = this.messageRepository.findAll();
return new ModelAndView("messages/list", "messages", messages);
}
@RequestMapping("{id}")
public ModelAndView view(@PathVariable("id") Message message) {
return new ModelAndView("messages/view", "message", message);
}
@RequestMapping(params = "form", method = RequestMethod.GET)
public String createForm(@ModelAttribute Message message) {
return "messages/form";
}
@RequestMapping(method = RequestMethod.POST)
public ModelAndView create(@Valid Message message, BindingResult result,
RedirectAttributes redirect) {
if (result.hasErrors()) {
return new ModelAndView("messages/form", "formErrors", result.getAllErrors());
}
message = this.messageRepository.save(message);
redirect.addFlashAttribute("globalMessage", "Successfully created a new message");
return new ModelAndView("redirect:/{message.id}", "message.id", message.getId());
}
@RequestMapping("foo")
public String foo() {
throw new RuntimeException("Expected exception in controller");
}
}
注：@Controller：1：spring的控制层。2：spring的注解之一放在类名之前3:spring配置文件中如果配置了扫描包路径，自动检测该注释的类并注入。4：spring控制层可以接收请求，并且返回响应。
@RequestMapping：用户请求路径是http://localhost:8080/项目名/类的@RequestMapping的value值/方法的@RequestMapping的value值。
@Autowired：依赖注入。
@PathVariable：rest访问方式获取参数传递
ModelAndView：一次性返回model和view2个对象,有7个构造函数，用来设定返回对象和视图，也可以用set方法设置。
@ModelAttribute：获取页面传递参数。也可以这样用
@ModelAttribute("user")
public User addAccount() {
return new User("jz","123");
}
@RequestMapping(value = "/helloWorld")
public String helloWorld(@ModelAttribute("user") User user) {
user.setUserName("jizhou");
return "helloWorld";
}
@SessionAttributes("user")用户同上只是使用范围不同而已。
RedirectAttributes：我的理解是controller控制层跳转到控制层传递参数用的。
@Valid：对实体类的一个验证。验证符合jpa的标准。要和BindingResult result配合使用，如果验证不通过的话，result.hasErrors()，跳转 。如一个实体类标准：
import javax.validation.constraints.Min;
import javax.validation.constraints.NotNull;
import org.hibernate.validator.constraints.NotBlank;
public class User {
private String username;
private String password;
private int age;
@NotBlank(message="用户名不能为空")
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
@NotNull(message="密码不能为null")
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
@Min(value=10, message="年龄的最小值为10")
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
}
最后个方法就是抛出页面异常.
html主要用ThyMeleaf标签，Thymeleaf是一个XML/XHTML/HTML5模板引擎，可用于Web与非Web环境中的应用开发。它是一个开源的Java库，基于Apache License 2.0许可，由Daniel Fernández创建，该作者还是Java加密库Jasypt的作者。
form.html代码如下：
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org"
xmlns:layout="http://www.ultraq.net.nz/web/thymeleaf/layout"
layout:decorator="layout">
<head>
<title>Messages : Create</title>
</head>
<body>
<h1 layout:fragment="header">Messages : Create</h1>
<div layout:fragment="content"
class="container">
<form id="messageForm"
th:action="@{/(form)}"
th:object="${message}"
action="#"
method="post">
<div th:if="${#fields.hasErrors('*')}"
class="alert alert-error">
<p th:each="error : ${#fields.errors('*')}"
th:text="${error}">
Validation error
</p>
</div>
<div class="pull-right">
<a th:href="@{/}" href="messages.html">
Messages
</a>
</div>
<label for="summary">Summary</label>
<input type="text"
th:field="*{summary}"
th:class="${#fields.hasErrors('summary')} ? 'field-error'"/>
<label for="text">Message</label>
<textarea
th:field="*{text}"
th:class="${#fields.hasErrors('text')} ? 'field-error'"></textarea>
<div class="form-actions">
<input type="submit" value="Create"/>
</div>
</form>
</div>
</body>
</html>
list.html代码如下：
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org"
xmlns:layout="http://www.ultraq.net.nz/web/thymeleaf/layout"
layout:decorator="layout">
<head>
<title>Messages : View all</title>
</head>
<body>
<h1 layout:fragment="header">Messages : View all</h1>
<div layout:fragment="content" class="container">
<div class="pull-right">
<a href="form.html" th:href="@{/(form)}">Create Message</a>
</div>
<table class="table table-bordered table-striped">
<thead>
<tr>
<td>ID</td>
<td>Created</td>
<td>Summary</td>
</tr>
</thead>
<tbody>
<tr th:if="${messages.empty}">
<td colspan="3">
No messages
</td>
</tr>
<tr th:each="message : ${messages}">
<td th:text="${message.id}">1</td>
<td th:text="${#calendars.format(message.created)}">
July 11, 2012 2:17:16 PM CDT
</td>
<td>
<a href="view.html"
th:href="@{'/' + ${message.id}}"
th:text="${message.summary}">
The summary
</a>
</td>
</tr>
</tbody>
</table>
</div>
</body>
</html>
view.html代码如下：
<html xmlns:th="http://www.thymeleaf.org"
xmlns:layout="http://www.ultraq.net.nz/web/thymeleaf/layout"
layout:decorator="layout">
<head>
<title>Messages : View</title>
</head>
<body>
<h1 layout:fragment="header">Messages : Create</h1>
<div layout:fragment="content"
class="container">
<div class="alert alert-success"
th:if="${globalMessage}"
th:text="${globalMessage}">
Some Success message
</div>
<div class="pull-right">
<a th:href="@{/}" href="list.html">
Messages
</a>
</div>
<dl>
<dt>ID</dt>
<dd id="id" th:text="${message.id}">123</dd>
<dt>Date</dt>
<dd id="created"
th:text="${#calendars.format(message.created)}">
July 11, 2012 2:17:16 PM CDT
</dd>
<dt>Summary</dt>
<dd id="summary"
th:text="${message.summary}">
A short summary...
</dd>
<dt>Message</dt>
<dd id="text"
th:text="${message.text}">
A detailed message that is longer than the summary.
</dd>
</dl>
</div>
</body>
</html>
注th标签的引用就是首先要注入标签头，xmlns:th="http://www.thymeleaf.org"放入html标签内就可以了，
# 代表 获取对象 从 messages bundle 也就是消息的资源本地化文件
$ 表示从model里面获取
<div class="col-sm-9">
<input type="text" th:field="*{id}" placeholder="Order Id" class="col-xs-10 col-sm-5" />
<p style="color:red" th:if="${#fields.hasErrors('*{id}')}" th:errors="*{id}"></p>
</div>
th:fragment=“public” 相当于 include标签
th:each="user : ${users}" 相当于c:foreach 使用时候
如上面
<tr th:each="user : ${users}">
<td th:text="${user.id}">01</td>
<td th:text="${user.name}">朱遇平</td>
<td th:text="${user.xx}">java</td>
<td th:text="${user.xx}">程序员</td>
</tr>
th:href="@{/}"动态设置url参数
<form action="#" th:action="@{/users/add}" th:object="${myuser}" method="post">
这里th：Object表示表单与 改myuser注入的实体映射，
在表单 th:field="*{id} 则表示 该表单的值 与 myuser的id绑定
th:if="${#fields.hasErrors('*')}"
th:if="${#strings.isEmpty(status)}"
${not #strings.isEmpty(status)}
if判断显示。
<div class="col-sm-9">
<input type="text" th:field="*{id}" placeholder="Order Id" class="col-xs-10 col-sm-5" />
<p style="color:red" th:if="${#fields.hasErrors('*{id}')}" th:errors="*{id}"></p>
</div>
th:errors错误信息显示如上图。