Thymeleaf的内置对象、SpringBoot整合Thymeleaf和JDBC

Thymeleaf的对象

Thymeleaf是直接支持访问Servlet web的原生资源，HttpServletRequest HttpServletResponse HttpSession ServletContext.

#request:获取HttpServletRequest对象

#response:获取HttpServletResponse 对象

#session：获取HttpSession 对象

#servletContext:获取ServletContext对象

1.Handler

@GetMapping("/servlet")

public String servlet(HttpServletRequest request){

    request.setAttribute("valye","request");

    request.getSession().setAttribute("valye","request");

    request.getServletContext().setAttribute("valye","request");

    return "test";

}

<!--request-->

        <p th:text="${#request.getAttribute('value')}"></p>

        <p th:text="${#session.getAttribute('value')}"></p>

        <p th:text="${#servletContext.getAttribute('value')}"></p>

        <p th:text="${#reponse}"></p>

Thymeleaf支持直接访问session，相对于

${#servletContext.getAttribute('value')}也可以简化为${value}

Thymeleaf的内置对象

dates;日期格式化
calendars：日期操作
numbers：数字格式化
Strings:字符格式化
bools：boolean
arrays：数组内置对象
lists：list集合内置对象
sets：set集合内置对象
maps;map集合内置对象

    @GetMapping("/uniltity")

    public ModelAndView uniltity(){

        ModelAndView modelAndView =new ModelAndView();

        modelAndView.setViewName("test");

        modelAndView.addObject("date",new Date());

        Calendar calendar =Calendar.getInstance();

        calendar.set(2020,1,1);

        modelAndView.addObject("calendar",calendar);

        modelAndView.addObject("number",0.06);

        modelAndView.addObject("string","Springboot");

        modelAndView.addObject("boolean",true);

        modelAndView.addObject("array",Arrays.asList("张三","李四","王五"));

        List<User> users = Arrays.asList(new User("张三",1),new User("李四",2),new User("王五",3));

        modelAndView.addObject("list",users);

        Set<User> set =new HashSet<>();

        set.add(new User("张三",1));

        set.add(new User("李四",2));

        modelAndView.addObject("set",set);

        Map<Integer,User> map=new HashMap<>();

        map.put(1,new User("张三",1));

        map.put(2,new User("李四",2));

        modelAndView.addObject("map",map);

        return modelAndView;

    }

date:格式化<span th:text="${#dates.format(date,'yyy-mm-dd')}"></span><br>

当前时间：<span th:text="${#dates.cteateToday()}"></span><br>

Calendar格式化：<span th:text="${#calendars.format(calendar,'yyyy-mm-dd')}"></span><br>

number百分比格式化:<span th:text="${#numbers.formatPercent(number,2,2)}"></span><br>

name是否为空:<span th:text="${#strings.isTmpty(string)}"></span><br>

name的长度:<span th:text="${#strings.length(string)}"></span><br>

name的拼接:<span th:text="${#strings.concat('Good',string)}"></span><br>

boolen是否为true：<span th:text="${#bools.isTrue(boolean)}"></span><br>

arrys的长度：<span th:text="${#arrays.length(array)}"></span><br>

array是否包含张三:<span th:text="${#arrays.contains(array,'张三')}"></span><br>

list是否为空:<span th:text="${#list.isEmpty(list)}"></span><br>

list的长度:<span th:text="${#list.size(list)}"></span><br>

Set是否为空：<span th:text="${#sets.isEmpty(set)}"></span><br>

Set的长度:<span th:text="${#sets.size(set)}"></span><br>

Map是否为空：<span th:text="${#maps.isEmpty(map)}"></span><br>

Map是的长度：<span th:text="${#maps.size(map)}"></span><br>

Spring boot 整合JDBC Template

JDBC Template是spring自带的一个JDBC的模版组件，底层实现了对JDBC的封装，用法和Mybatis类似，需要开发者定义SQL语句，JDBC Template帮助我们完成数据库的连接，SQL的执行，结果集的封装

不足之处灵活性不如Mybatis，因为Mybatis是直接卸载XML王文建中，更有利于扩展和维护，JDBC Template是以硬编码的形式将SQL直接写在java代码中，不利于扩展和维护

1.pom.xml

<?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>org.example</groupId>

    <artifactId>soringbootdo</artifactId>

    <version>1.0-SNAPSHOT</version>

    <parent>

        <artifactId>spring-boot-starter-web</artifactId>

        <groupId>org.springframework.boot</groupId>

        <version>2.2.4.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-jdbc</artifactId>

        </dependency>

        <dependency>

            <groupId>mysql</groupId>

            <artifactId>mysql-connector-java</artifactId>

        </dependency>

        <dependency>

            <groupId>org.projectlombok</groupId>

            <artifactId>lombok</artifactId>

        </dependency>

    </dependencies>

</project>

2.实体类：

package com.southwind.entity;

import lombok.Data;

@Data

public class User {

    private Integer id;

    private  String name;

    private  Integer money;

}

3.Repository

接口：

package com.southwind.Repository;

import com.southwind.entity.User;

import java.util.List;

public interface UserRepository {

    public List<User> findAll();

    public  User finById(Integer id);

    public int save (User user);

    public  int update(User user);

    public  int delete(Integer id);

}

package com.southwind.Repository.impl;

import com.southwind.Repository.UserRepository;

import com.southwind.entity.User;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.jdbc.core.BeanPropertyRowMapper;

import org.springframework.jdbc.core.JdbcTemplate;

import org.springframework.stereotype.Repository;

import java.util.List;

@Repository

public class UserRepositoryImpl implements UserRepository {

    @Autowired

    private JdbcTemplate jdbcTemplate;

    public List<User> findAll() {

        return jdbcTemplate.query(

                "select * from people",

                new BeanPropertyRowMapper<>(User.class)

        );

    }

    public User finById(Integer id) {

        return jdbcTemplate.queryForObject(

                "select * from people where id=?",

                new Object[]{id},

                new BeanPropertyRowMapper<>(User.class)

        );

    }

    public int save(User user) {

        return jdbcTemplate.update(

                "insert into people(id,name,money) values (?,?,?)",

                user.getId(),

                user.getName(),

                user.getMoney()

        );

    }

    public int update(User user) {

        return jdbcTemplate.update(

                "update people set name=?,money=? where  id=?",

                user.getName(),

                user.getMoney(),

                user.getId()

        );

    }

    public int delete(Integer id) {

        return jdbcTemplate.update(

                "delete from people where id=?",

                id

        );

    }

}

4.Handeler

package com.southwind.Controller;

import com.southwind.Repository.UserRepository;

import com.southwind.Repository.impl.UserRepositoryImpl;

import com.southwind.entity.User;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Controller;

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

import java.util.List;

@Controller

@RequestMapping("/user")

public class UserHandler {

    @Autowired

    private UserRepositoryImpl userRepository;

    @GetMapping("/findall")

    @ResponseBody

    public List<User> findall(){

        return userRepository.findAll();

    }

    @GetMapping("/findbyid/{id}")

    @ResponseBody

    public User findbyid(@PathVariable("id")Integer id) {

        return userRepository.finById(id);

    }

    @PostMapping("/save")

    @ResponseBody

    public int save(@RequestBody User user){

        return userRepository.save(user);

    }

    @PutMapping("/update")

    @ResponseBody

    public int update(@RequestBody User user){

        return userRepository.update(user);

    }

    @DeleteMapping("/delete/{id}")

    @ResponseBody

    public int delete(@PathVariable Integer id){

        return userRepository.delete(id);

    }

}

方法

query：

public <T> List<T> query(String sql, RowMapper<T> rowMapper) throws DataAccessException {

    return (List)result(this.query((String)sql, (ResultSetExtractor)(new RowMapperResultSetExtractor(rowMapper))));

}

RowMapper是一个接口，作用是分析结果集，将JDBC查询的ResultSet对象转化成对应的POJO

queryForObjiect(String sql,Object[] args, RowMapper rowMapper)

该方法查询一条数据，并将结果封装成一个POJO

update

public int update(String sql, @Nullable Object... args) throws DataAccessException {

    return this.update(sql, this.newArgPreparedStatementSetter(args));

}

增加、修改、删除都可以用这个方法

巴特西

Thymeleaf的内置对象、SpringBoot整合Thymeleaf和JDBC

Thymeleaf的对象

Thymeleaf的内置对象

Spring boot 整合JDBC Template

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