Thymeleaf是用于Web和独立环境的现代服务器端Java模板引擎。Thymeleaf的主要目标是将优雅的自然模板带到您的开发工作流程中—HTML能够在浏览器中正确显示，并且可以作为静态原型，从而在开发团队中实现更强大的协作。Thymeleaf能够处理HTML，XML，JavaScript，CSS甚至纯文本。

整合thymeleaf

修改pom.xml文件,添加依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.1.3.RELEASE</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.caicai</groupId>
	<artifactId>10-spring-boot-view-thymeleaf</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>10-spring-boot-view-thymeleaf</name>
	<description>Demo project for Spring Boot</description>

	<properties>
		<java.version>1.8</java.version>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-thymeleaf</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>

</project>

编写视图:

在templates/ 下建立 userList2.html:

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" xmlns:th="http://www.thymeleaf.org"
      xmlns:sec="http://www.thymeleaf.org/thymeleaf-extras-springsecurity3">
<head>
    <title>index</title>
</head>
<body>
<table border="1" align="center" width="50%">
    <tr>
        <th>ID</th>
        <th>Name</th>
        <th>Age</th>
    </tr>

    <tr th:each="user:${list}">
        <td th:text="${user.userid}"></td>
        <td th:text="${user.username}"></td>
        <td th:text="${user.userage}"></td>
    </tr>

</table>
</body>
</html>

创建Controller

package com.caicai.springbootviewfreemarker.controller;

import com.caicai.springbootviewfreemarker.pojo.Users;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

import java.util.ArrayList;
import java.util.List;

/**
 * @author liu
 * @title: UserController
 * @projectName 08-spring-boot-view-jsp
 * @description: TODO
 * @date 2019/3/2820:06
 */
@Controller
public class UserController {
    @RequestMapping("/showuser2")
    public String index(Model model){
        List<Users> list = new ArrayList<>();
        list.add(new Users(1,"caicai",21));
        list.add(new Users(2,"honghong",32));
        list.add(new Users(3,"mingming",43));
        model.addAttribute("list",list);
        return "userList2";
    }
}

创建Users类:

package com.caicai.springbootviewfreemarker.pojo;

/**
 * @author liu
 * @title: Users
 * @projectName 08-spring-boot-view-jsp
 * @description: TODO
 * @date 2019/3/2820:06
 */
public class Users {
    private Integer userid;
    private String username;
    private Integer userage;



    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public Integer getUserage() {
        return userage;
    }

    public void setUserage(Integer userage) {
        this.userage = userage;
    }

    public Users() {
    }

    public Integer getUserid() {
        return userid;
    }

    public void setUserid(Integer userid) {
        this.userid = userid;
    }

    public Users(Integer userid, String username, Integer userage) {
        this.userid = userid;
        this.username = username;
        this.userage = userage;
    }
}

创建启动类

package com.caicai.springbootviewfreemarker;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class Application {

	public static void main(String[] args) {
		SpringApplication.run(Application.class, args);
	}

}

thymeleaf基本语法:

变量输出与字符串操作

th:text

在页面中输出值

th:value

可以将一个值放入到 input 标签的 value 中

判断字符串是否为空

Thymeleaf 内置对象
注意语法：
1，调用内置对象一定要用#
2，大部分的内置对象都以 s 结尾 strings、numbers、dates

${#strings.isEmpty(key)}
判断字符串是否为空，如果为空返回 true，否则返回 false
${#strings.contains(msg,'T')}
判断字符串是否包含指定的子串，如果包含返回 true，否则返回 false
${#strings.startsWith(msg,'a')}
判断当前字符串是否以子串开头，如果是返回 true，否则返回 false
${#strings.endsWith(msg,'a')}
判断当前字符串是否以子串结尾，如果是返回 true，否则返回 false
${#strings.length(msg)}
返回字符串的长度
${#strings.indexOf(msg,'h')}
查找子串的位置，并返回该子串的下标，如果没找到则返回-1
${#strings.substring(msg,13)}
${#strings.substring(msg,13,15)}
截取子串，用户与 jdk String 类下 SubString 方法相同
${#strings.toUpperCase(msg)}
${#strings.toLowerCase(msg)}
字符串转大小写。

日期格式化处理

${#dates.format(key)}
格式化日期，默认的以浏览器默认语言为格式化标准
${#dates.format(key,'yyy/MM/dd')}
按照自定义的格式做日期转换
${#dates.year(key)}
${#dates.month(key)}
${#dates.day(key)}
year：取年
Month：取月
Day：取日

条件判断

th:if

<span th:if="${sex} == '男'">
    性别男
</span>
<span th:if="${sex} == '女'">
    性别女
</span>

th:switch

<span th:switch="${id}">
    <span th:case="1">ID 为1</span>
    <span th:case="2">ID 为2</span>
    <span th:case="2">ID 为3</span>
</span>

迭代遍历

<table border="1" align="center" width="50%">
    <tr>
        <th>ID</th>
        <th>Name</th>
        <th>Age</th>
    </tr>

    <tr th:each="user:${list}">
        <td th:text="${user.userid}"></td>
        <td th:text="${user.username}"></td>
        <td th:text="${user.userage}"></td>
    </tr>

</table>

@RequestMapping("/index")
public String index(Model model){
    List<Users> list = new ArrayList<>();
    list.add(new Users(1,"caicai",21));
    list.add(new Users(2,"honghong",32));
    list.add(new Users(3,"mingming",43));
    model.addAttribute("list",list);
    return "index";

}

状态变量属性
1,index:当前迭代器的索引从 0 开始
2,count:当前迭代对象的计数从 1 开始
3,size:被迭代对象的长度
4,even/odd:布尔值，当前循环是否是偶数/奇数从 0 开始
5,first:布尔值，当前循环的是否是第一条，如果是返回 true 否则返回 false
6,last:布尔值，当前循环的是否是最后一条，如果是则返回 true 否则返回 false

th:each 迭代Map

<table border="1">
    <tr>
        <th>ID</th>
        <th>Name</th>
        <th>Age</th>
    </tr>
    <tr th:each="maps : ${map}">
        <td th:text="${maps}"></td>
    </tr>
</table>
<th/>
<table border="1">
    <tr>
        <th>ID</th>
        <th>Name</th>
        <th>Age</th>
    </tr>
    <tr th:each="maps : ${map}">
        <td th:each="entry:${maps}"
            th:text="${entry.value.id}" ></td>
        <td th:each="entry:${maps}"
            th:text="${entry.value.name}"></td>
        <td th:each="entry:${maps}"
            th:text="${entry.value.age}"></td>
    </tr>
</table>


@RequestMapping("/index3")
public String index3(Model model){
    Map<String, User> map = new HashMap<>();
    map.put("u1", new User(1,"张三",20));
    map.put("u2", new User(2,"李四",22));
    map.put("u3", new User(3,"王五",24));
    model.addAttribute("map", map);
    return "index3" ;
}

域对象操作

@RequestMapping("/index4")
public String index4(HttpServletRequest httpServletRequest, Model model){
    httpServletRequest.setAttribute("req","HttpServletRequest");
    httpServletRequest.getSession().setAttribute("sess","HttpSession");
    httpServletRequest.getSession().getServletContext().setAttribute("app","Application");
    return "index4" ;
}

<body>
<span th:text="${#httpServletRequest.getAttribute('req')}"></span><br>
<span th:text="${session.sess}"></span><br>
<span th:text="${application.app}"></span><br>
</body>

URL表达式

th:href
th:src

URL表达式语法

基本语法：@{}

URL类型

绝对路径

1	<a th:href="@{http://www.baidu.com}">绝对路径</a><br/>

相对路径

1)相对于当前项目的根
相对于项目的上下文的相对路径

1	<a th:href="@{/show}">相对路径</a>

相对于服务器路径的根

1	<a th:href="@{~/project2/resourcename}">相对于服务器的根</a>

在 url 中实现参数传递

1	<a th:href="@{/show(id=1,name=zhagnsan)}">相对路径-传参</a>

在 url 中通过 restful 风格进行参数传递

1 2	<a th:href="@{/path/{id}/show(id=1,name=zhagnsan)}"> 相对路径 - 传参 -restful</a>