springboot入门

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springio

spring boot

Spring Boot 是一个快速开发框架、Spring boot开启了自动装配、从而简化代码开发、不需要编写各种该配置文件、只需要引入相关依赖就可以迅速搭建一个应用

  • 特点

不需要web.xml
不需要springmvc.xml
不需要tomcat、spring boot本身内嵌tomcat
不需要JSON解析、支持REST

spring boot简单搭建

  • pom.xml
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<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.0.7.RELEASE</version>
  </parent>

  <dependencies>

    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
  </dependencies>
  • Application启动类
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@SpringBootApplication
public class Appliaction {
    public static void main(String[] args) {
        SpringApplication.run(Appliaction.class,args);
    }
}

spring boot整合JSP

  • pom.xml
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<!-- 继承父包 -->
  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.0.7.RELEASE</version>
  </parent>

  <dependencies>
    <!-- web启动jar -->
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

<!--    整合jsp-->
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-tomcat</artifactId>
    </dependency>
    <dependency>
      <groupId>org.apache.tomcat.embed</groupId>
      <artifactId>tomcat-embed-jasper</artifactId>
    </dependency>


<!--    jstl-->
    <dependency>
      <groupId>jstl</groupId>
      <artifactId>jstl</artifactId>
      <version>1.2</version>
    </dependency>

<!--    lombok-->
    <dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
      <version>1.18.6</version>
      <scope>provided</scope>
    </dependency>

  </dependencies>
  • pojo
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@Data
@AllArgsConstructor
@NoArgsConstructor
public class Student {

    private Long id;
    private String name;
    private Integer sex;
    private Integer age;
}
  • controller
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@Controller
@RequestMapping(value = "/student")
public class StudentController {

    @Autowired
    private StudentRepositoryImpl studentRepository;

    @GetMapping(value = "/index")
    public ModelAndView findAll(){

        ModelAndView modelAndView =
                new ModelAndView("index","collection",studentRepository.findAll());

        return modelAndView;
    }

    @GetMapping(value = "/findById/{id}")
    public ModelAndView findById(@PathVariable("id") Long id){

        ModelAndView modelAndView =
                new ModelAndView("update","student",studentRepository.findById(id));

        return modelAndView;
    }

    @DeleteMapping(value = "/deleteById/{id}")
    public String deleteById(@PathVariable("id") Long id){
        studentRepository.deleteById(id);
        return "redirect:/student/index";
    }

    @PostMapping(value = "/save")
    public void save(@RequestBody  Student student){
        studentRepository.saveAndUpdate(student);
    }

    @PutMapping(value = "/update")
    public String update(Student student){
        studentRepository.saveAndUpdate(student);

        return "redirect:/student/index";
    }
}
  • repository
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@Repository
public class StudentRepositoryImpl implements StudentRepository {

    private static Map<Long, Student> map = null;

    static{
        map = new HashMap<>();
        map.put(1L,new Student(1L,"xiaobo",0,21));
        map.put(2L,new Student(2L,"h",1,21));
        map.put(3L,new Student(3L,"pangzi",0,22));
    }

    @Override
    public Collection<Student> findAll() {

        return map.values();
    }

    @Override
    public Student findById(Long id) {
        return map.get(id);
    }

    @Override
    public void deleteById(Long id) {
        map.remove(id);
    }

    @Override
    public void saveAndUpdate(Student student) {
        map.put(student.getId(),student);
    }
}
  • application.yml
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server:
  port: 8080
spring:
  mvc:
    view:
      prefix: /
      suffix: .jsp
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<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ page isELIgnored="false" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<script type="text/javascript" src="js/jquery-3.2.1.min.js"></script>
<html>
<head>
    <title>首页</title>
</head>
<body>
    <h1>学生信息</h1>
    <table>
        <tr>
            <th>编号</th>
            <th>姓名</th>
            <th>性别</th>
            <th>年龄</th>
            <th>操作</th>
        </tr>
        <c:forEach items="${collection }" var="student">
            <tr>
                <td>${student.id }</td>
                <td>${student.name }</td>
                <c:if test="${student.sex == 0}">
                    <td>男</td>
                </c:if>
                <c:if test="${student.sex == 1}" var="女">
                    <td>女</td>
                </c:if>
                <td>${student.age }</td>
                <td>
                    <form action="/student/findById/${student.id }" method="get">
                        <input type="submit" value="修改" />
                    </form>
                </td>
                <td>
                    <form action="/student/deleteById/${student.id }" method="post">
                        <input type="hidden" name="_method" value="delete"/>
                        <input type="submit" value="删除" />
                    </form>
                </td>
            </tr>
        </c:forEach>
    </table>
    <input id="addBut" type="button" value="添加学生" />
</body>
</html>

spring boot 整合thymeleaf模板

  • pom.xml
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<dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-thymeleaf</artifactId>
    </dependency>
  • controller
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@Controller
@RequestMapping(value = "/student")
public class StudentController {

    private static List<Student> list = null;

    static{
        list = new ArrayList<>();
        list.add(new Student(1L,"xiaobo",21));
        list.add(new Student(2L,"pangzi",22));
        list.add(new Student(3L,"h",21));
    }

    @GetMapping(value = "/index")
    public String findAll(Model model){
        model.addAttribute("list",list);
        return "index";
    }
}
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<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org"></html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>首页</title>
</head>
<body>

    <h1>学生信息</h1>
    <table>
        <tr>
            <th>编号</th>
            <th>姓名</th>
            <th>年龄</th>
        </tr>
        <tr th:each="student:${list }">
            <td th:text="${student.id }"></td>
            <td th:text="${student.name}"></td>
            <td th:text="${student.age}"></td>
        </tr>
    </table>

</body>
</html>
  • application.yml
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server:
  port: 8080

spring:
  thymeleaf:
    prefix: classpath:/templates/
    suffix: .html
    mode: HTML
    encoding: UTF-8

Thymeleaf语法

  • 赋值、拼接
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<p th:text="${name}"></p>
<p th:text="'学生姓名是'+${name}+ good"></p>
<p th:text="|学生姓名是,${name}|"></p>
  • th:if
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<p th:if="${flag == true}" th:text="if判断成立"></p>
<p th:unless="${flag != true}" th:text="unless判断成立"></p>
  • th:each
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<tr th:each="student,stat:${list}">
    <td th:text="${stat.index}"></td>
    <td th:text="${stat.count}"></td>
    <td th:text="${student.id}"></td>
    <td th:text="${student.name}"></td>
    <td th:text="${student.age}"></td>
  </tr>
  • stat 是状态变量，属性：

index 集合中元素的index（从0开始）
count 集合中元素的count（从1开始）
size 集合的大小
current 当前迭代变量
even/odd 当前迭代是否为偶数/奇数（从0开始计算）
first 当前迭代的元素是否是第一个
last 当前迭代的元素是否是最后一个

  • url
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<a th:href="@{http://www.baidu.com}">跳转</a>
  • 三元运算符
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<input th:value="${age gt 30?'中年':'青年'}"/>

gt great than 大于
ge great equal 大于等于
eq equal 等于
lt less than 小于
le less equal 小于等于
ne not equal 不等于

  • switch
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<div th:switch="${gender}">
  <p th:case="女">女</p>
  <p th:case="男">男</p>
  <p th:case="*">未知</p>
</div>

基本对象

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

#ctx ：上下文对象
#vars：上下文变量
#locale：区域对象
#request：HttpServletRequest 对象
#response：HttpServletResponse 对象
#session：HttpSession 对象
#servletContext：ServletContext 对象

内嵌对象

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<!-- 格式化时间 -->
<p th:text="${#dates.format(date,'yyyy-MM-dd HH:mm:sss')}"></p>
<!-- 创建当前时间，精确到天 -->
<p th:text="${#dates.createToday()}"></p>
<!-- 创建当前时间，精确到秒 -->
<p th:text="${#dates.createNow()}"></p>
<!-- 判断是否为空 -->
<p th:text="${#strings.isEmpty(name)}"></p>
<!-- 判断List是否为空 -->
<p th:text="${#lists.isEmpty(users)}"></p>
<!-- 输出字符串长度 -->
<p th:text="${#strings.length(name)}"></p>
<!-- 拼接字符串 -->
<p th:text="${#strings.concat(name,name,name)}"></p>
<!-- 创建自定义字符串 -->
<p th:text="${#strings.randomAlphanumeric(count)}"></p>

dates：java.util.Date 的功能方法
calendars：java.util.Calendar 的功能方法
numbers：格式化数字
strings：java.lang.String 的功能方法
objects：Object 的功能方法
bools：对布尔求值的方法
arrays：操作数组的功能方法
lists：操作集合的功能方法
sets：操作集合的功能方法
maps：操作集合的功能方法

spring boot 数据校验

  • pojo
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@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {

    @NotNull(message = "id不能为空")
    private Long id;

    @NotEmpty(message = "用户名不能为空")
    @Length(min = 3,message = "用户名长度不能小于3位")
    private String username;

    @NotEmpty(message = "密码不能为空")
    @Length(min = 6,message = "密码长度不能小于6位")
    private String password;
}
  • validator
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@RestController
@RequestMapping(value = "/user")
public class UserController {

    @RequestMapping(value = "/login")
    public void validatorUser(@Valid User user, BindingResult bindingResult, Model model){
        if(bindingResult.hasErrors()) {
            List<ObjectError> allErrors =
                    bindingResult.getAllErrors();

            for (ObjectError objectError : allErrors) {
                System.out.println(objectError.getCode());
                System.out.println(objectError.getDefaultMessage());
            }
        }
    }
}

spring boot整合JDBC

  • pom.xml
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<dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-jdbc</artifactId>
    </dependency>

    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>8.0.11</version>
    </dependency>
  • controller
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@RestController
@RequestMapping(value = "/user")
public class UserController {

    @Autowired
    private UserRepositoryImpl userRepository;

    @GetMapping(value = "/findAll")
    public List<User> findAll(Model model){

//        model.addAttribute("users",userRepository.findAll());

        return userRepository.findAll();
    }

    @GetMapping(value = "/findById/{id}")
    public User findById(@PathVariable("id") Long id){
//            userRepository.findById(id);
        System.out.println(userRepository.findById(id));
        return userRepository.findById(id);
    }

    @PostMapping(value = "/save")
    public void save(@RequestBody User user){

        userRepository.save(user);

    }

    @DeleteMapping(value = "/delete/{id}")
    public void deleteById(@PathVariable("id") Long id){
        userRepository.deleteById(id);
    }

    @PutMapping(value = "/update")
    public void update(@RequestBody User user){

        userRepository.update(user);

    }
}
  • repository
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@Repository
public class UserRepositoryImpl implements UserRepository {

    @Autowired
    private JdbcTemplate jdbcTemplate;

    @Override
    public List<User> findAll() {
        return jdbcTemplate.query("SELECT * FROM user",new BeanPropertyRowMapper<>(User.class));
    }

    @Override
    public User findById(Long id) {

        return jdbcTemplate.queryForObject("SELECT * FROM user WHERE id = ?",
                new Object[]{id},new BeanPropertyRowMapper<>(User.class));
    }

    @Override
    public void save(User user) {
        jdbcTemplate.update("INSERT INTO user(id,username,password) VALUES(?,?,?)",user.getId(),user.getUsername(),user.getPassword());
    }

    @Override
    public void deleteById(Long id) {
        jdbcTemplate.update("DELETE FROM user WHERE id = ?",id);
    }

    @Override
    public void update(User user) {
        jdbcTemplate.update("UPDATE user SET username = ?,password=? WHERE id = ?",user.getUsername(),user.getPassword(),user.getId());
    }
}
  • application.yml
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server:
  port: 8080

spring:
  thymeleaf:
    prefix: classpath:/templates/
    suffix: .html
    mode: HTML
    encoding: UTF-8
  datasource:
    url: jdbc:mysql://localhost:3306/db_mybatis?useUnicode=true&charcaterEncoding=UTF-8&serverTimezone=UTC
    username: root
    password: xiaobo
    driver-class-name: com.mysql.cj.jdbc.Driver

springboot 整合Mybatis

  • pom.xml
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<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.11</version>
        </dependency>

        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.1</version>
        </dependency>
  • application.yml
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mybatis:
  mapper-locations: classpath:/mapping/*.xml
  type-aliases-package: com.dream.xiaobo.pojo

server:
  port: 8080


spring:
  datasource:
    url: jdbc:mysql://localhost:3306/db_mybatis?useUnicode=true&charcaterEncoding=UTF-8&serverTimezone=UTC
    username: root
    password: xiaobo
    driver-class-name: com.mysql.cj.jdbc.Driver
  • repository
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public interface UserRepository {

    public List<User> findAll();

    public User findById(Long id);

    public void save(User user);

    public void deleteById(Long id);

    public void update(User user);
}
  • mapper
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<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="com.dream.xiaobo.repository.UserRepository">
    <select id="findAll" resultType="User">
        SELECT * FROM user
    </select>
    <select id="findById" resultType="User" parameterType="java.lang.Long">
        SELECT * FROM user WHERE id = #{id }
    </select>
    <insert id="save" parameterType="User">
        INSERT INTO user(username,password) VALUES(#{username },#{password })
    </insert>
    <update id="update" parameterType="User">
        UPDATE user SET username = #{username},password = #{password } WHERE id = #{id }
    </update>
    <delete id="deleteById" parameterType="java.lang.Long">
        DELETE FROM user WHERE id = #{id }
    </delete>
</mapper>
  • controller
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@RestController
@RequestMapping(value = "/user")
public class UserController {

    @Autowired
    private UserRepository userRepository;

    @GetMapping(value = "/findAll")
    public List<User> findAll(Model model){


        return userRepository.findAll();
    }

    @GetMapping(value = "/findById/{id}")
    public User findById(@PathVariable("id") Long id){
        System.out.println(userRepository.findById(id));
        return userRepository.findById(id);
    }

    @PostMapping(value = "/save")
    public void save(@RequestBody User user){

        userRepository.save(user);

    }

    @DeleteMapping(value = "/delete/{id}")
    public void deleteById(@PathVariable("id") Long id){
        userRepository.deleteById(id);
    }

    @PutMapping(value = "/update")
    public void update(@RequestBody User user){

        userRepository.update(user);
    }
}
  • application
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@SpringBootApplication
@MapperScan("com.dream.xiaobo.repository")//将repository包下的放入到容器中
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class,args);
    }
}
-------------本文结束 感谢您的阅读-------------

本文标题:springboot入门

文章作者:小博

发布时间:2021年07月22日 - 18:22

最后更新:2021年07月22日 - 18:25

原始链接:https://codexiaobo.github.io/posts/1686262074/

许可协议: 署名-非商业性使用-禁止演绎 4.0 国际 转载请保留原文链接及作者。