create database how2java;
use how2java;
CREATE TABLE category_ (
  id int(11) NOT NULL AUTO_INCREMENT,
  name varchar(30),
  PRIMARY KEY (id)
) DEFAULT CHARSET=UTF8;

#thymeleaf 配置
spring.thymeleaf.mode=HTML5
spring.thymeleaf.encoding=UTF-8
spring.thymeleaf.content-type=text/html
#缓存设置为false, 这样修改之后马上生效，便于调试
spring.thymeleaf.cache=false
#上下文
server.context-path=/thymeleaf

#数据库
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/how2java?characterEncoding=UTF-8
spring.datasource.username=root
spring.datasource.password=admin
spring.datasource.driver-class-name=com.mysql.jdbc.Driver

<?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>

  <groupId>com.how2java</groupId>
  <artifactId>thymeleaf</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <name>thymeleaf</name>
  <description>thymeleaf</description>
  <packaging>war</packaging>
  
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.9.RELEASE</version>
    </parent>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
	    <dependency>
	      <groupId>org.springframework.boot</groupId>
	      <artifactId>spring-boot-starter-thymeleaf</artifactId>
	    </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            
        </dependency>
	    <dependency>
		      <groupId>junit</groupId>
		      <artifactId>junit</artifactId>
		      <version>3.8.1</version>
		      <scope>test</scope>
	    </dependency>
  		<!-- servlet依赖. -->
        <dependency>
              <groupId>javax.servlet</groupId>
              <artifactId>javax.servlet-api</artifactId>
              
        </dependency>
              <dependency>
                     <groupId>javax.servlet</groupId>
                     <artifactId>jstl</artifactId>
              </dependency>
        <!-- tomcat的支持.-->
        <dependency>
               <groupId>org.apache.tomcat.embed</groupId>
               <artifactId>tomcat-embed-jasper</artifactId>
               
        </dependency>	    
		<dependency>
		    <groupId>org.springframework.boot</groupId>
		    <artifactId>spring-boot-devtools</artifactId>
		    <optional>true</optional> <!-- 这个需要为 true 热部署才有效 -->
		</dependency>    
		<!-- mybatis -->
		<dependency>
			<groupId>org.mybatis.spring.boot</groupId>
			<artifactId>mybatis-spring-boot-starter</artifactId>
			<version>1.1.1</version>
		</dependency>
		<!-- mysql -->
		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
			<version>5.1.21</version>
		</dependency>		
		<!-- pageHelper -->
		<dependency>
			<groupId>com.github.pagehelper</groupId>
			<artifactId>pagehelper</artifactId>
			<version>4.1.6</version>
		</dependency>
    </dependencies>

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

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

</project>

package com.how2java.springboot.pojo;
 
public class Category {
  
    private int id;
      
    private String 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;
    }
      
}

package com.how2java.springboot.mapper;
 
import java.util.List;
 
import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;
 
import com.how2java.springboot.pojo.Category;
 
@Mapper
public interface CategoryMapper {
 
    @Select("select * from category_ ")
    List<Category> findAll();
     
    @Insert(" insert into category_ ( name ) values (#{name}) ")
    public int save(Category category); 
     
    @Delete(" delete from category_ where id= #{id} ")
    public void delete(int id);
         
    @Select("select * from category_ where id= #{id} ")
    public Category get(int id);
       
    @Update("update category_ set name=#{name} where id=#{id} ")
    public int update(Category category); 
 
}

package com.how2java.springboot.web;
import java.util.List;

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

import com.github.pagehelper.PageHelper;
import com.github.pagehelper.PageInfo;
import com.how2java.springboot.mapper.CategoryMapper;
import com.how2java.springboot.pojo.Category;
   
@Controller
public class CategoryController {
    @Autowired CategoryMapper categoryMapper;
      
    @RequestMapping("/addCategory")
    public String listCategory(Category c) throws Exception {
        categoryMapper.save(c);
        return "redirect:listCategory";
    }
    @RequestMapping("/deleteCategory")
    public String deleteCategory(Category c) throws Exception {
        categoryMapper.delete(c.getId());
        return "redirect:listCategory";
    }
    @RequestMapping("/updateCategory")
    public String updateCategory(Category c) throws Exception {
        categoryMapper.update(c);
        return "redirect:listCategory";
    }
    @RequestMapping("/editCategory")
    public String listCategory(int id,Model m) throws Exception {
        Category c= categoryMapper.get(id);
        m.addAttribute("c", c);
        return "editCategory";
    }
     
    @RequestMapping("/listCategory")
    public String listCategory(Model m,@RequestParam(value = "start", defaultValue = "0") int start,@RequestParam(value = "size", defaultValue = "5") int size) throws Exception {
    	PageHelper.startPage(start,size,"id desc");
        List<Category> cs=categoryMapper.findAll();
        PageInfo<Category> page = new PageInfo<>(cs);
        m.addAttribute("page", page);        
        return "listCategory";
    }
     
}

package com.how2java.springboot.config;
 
import java.util.Properties;
 
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
 
import com.github.pagehelper.PageHelper;
 
@Configuration
public class PageHelperConfig {
 
    @Bean
    public PageHelper pageHelper() {
        PageHelper pageHelper = new PageHelper();
        Properties p = new Properties();
        p.setProperty("offsetAsPageNum", "true");
        p.setProperty("rowBoundsWithCount", "true");
        p.setProperty("reasonable", "true");
        pageHelper.setProperties(p);
        return pageHelper;
    }
}

<!DOCTYPE HTML>
<html xmlns:th="http://www.thymeleaf.org">
<head>
    <title>hello</title>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
</head>
<body>

<div style="width:500px;margin:20px auto;text-align: center">
    <table align='center' border='1' cellspacing='0'>
        <tr>
            <td>id</td>
            <td>name</td>
            <td>编辑</td>
            <td>删除</td>
        </tr>
        <tr th:each="c:${page.list}">
            <td th:text="${c.id}"></td>
            <td th:text="${c.name}"></td>
            <td><a th:href="@{/editCategory(id=${c.id})}">编辑</a></td>
            <td><a th:href="@{/deleteCategory(id=${c.id})}">删除</a></td>
        </tr>
    </table>
    <br/>
    <div>
			<a th:href="@{/listCategory(start=0)}">[首  页]</a>
			<a th:href="@{/listCategory(start=${page.pageNum-1})}">[上一页]</a>
			<a th:href="@{/listCategory(start=${page.pageNum+1})}">[下一页]</a>
			<a th:href="@{/listCategory(start=${page.pages})}">[末  页]</a>
    </div>
    <br/>    
    <form action="addCategory" method="post">
      
    name: <input name="name"/> <br/>
    <button type="submit">提交</button>
      
    </form>
</div>

</body>
</html>

<!DOCTYPE HTML>
<html xmlns:th="http://www.thymeleaf.org">
<head>
    <title>hello</title>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
</head>
<body>
<div style="margin:0px auto; width:500px">
  
	<form action="updateCategory" method="post">
	  
	name: <input name="name" th:value="${c.name}"/> <br/>
	  
	<input name="id" type="hidden" th:value="${c.id}"/>
	<button type="submit">提交</button>
	  
	</form>
</div>
</body>

</html>