Spring Boot入门

Spring Boot

Spring Boot 是一个快速开发框架，是为了简化Spring繁琐配置的快速开发整合包，是 Spring Cloud 的基础。

Spring Boot 开启了各种自动装配，降低项目构建的复杂度，不需要编写各种XML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

1、不需要 web.xml

2、不需要 springmvc.xml

3、不需要 tomcat，Spring Boot 内嵌了 tomcat

4、不需要配置 JSON 解析，支持 REST 架构

5、个性化配置非常简单

• 如何使用

1、创建 Maven 工程，导入相关依赖。

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

2、创建 Student 实体类

view codepackage com.oeong.entity;

import lombok.Data;

@Data
public class Student {
    private long id;
    private String name;
    private int age;
}

3、StudentRepository

view codepackage com.oeong.repository;

import com.oeong.entity.Student;

import java.util.Collection;

public interface StudentRepository {
    public Collection<Student> findAll();
    public Student findById(long id);
    public void saveOrUpdate(Student student);
    public void deleteById(long id);
}

4、StudentRepositoryImpl

view codepackage com.oeong.repository.impl;

import com.oeong.entity.Student;
import com.oeong.repository.StudentRepository;
import org.springframework.stereotype.Repository;

import java.util.Collection;
import java.util.HashMap;
import java.util.Map;

@Repository
public class StudentRepositoryImpl implements StudentRepository {

    private static Map<Long,Student> studentMap;

    static{
        studentMap = new HashMap<>();
        studentMap.put(1L,new Student(1L,"张三",22));
        studentMap.put(2L,new Student(2L,"李四",23));
        studentMap.put(3L,new Student(3L,"王五",24));
    }

    @Override
    public Collection<Student> findAll() {
        return studentMap.values();
    }

    @Override
    public Student findById(long id) {
        return studentMap.get(id);
    }

    @Override
    public void saveOrUpdate(Student student) {
        studentMap.put(student.getId(),student);
    }

    @Override
    public void deleteById(long id) {
        studentMap.remove(id);
    }
}

5、StudentHandler

view codepackage com.oeong.controller;

import com.oeong.entity.Student;
import com.oeong.repository.StudentRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.Collection;

@RestController
@RequestMapping("/student")
public class StudentHandler {

    @Autowired
    private StudentRepository studentRepository;

    @GetMapping("/findAll")
    public Collection<Student> findAll(){
        return studentRepository.findAll();
    }

    @GetMapping("/findById/{id}")
    public Student findById(@PathVariable("id") long id){
        return studentRepository.findById(id);
    }

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

    @PutMapping("/update")
    public void update(@RequestBody Student student){
        studentRepository.saveOrUpdate(student);
    }

    @DeleteMapping("/deleteById/{id}")
    public void deleteById(@PathVariable("id") long id){
        studentRepository.deleteById(id);
    }
}

6、application.yml

view codeserver:
  port: 8181

7、启动类

view codepackage com.oeong;

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);
    }
}

@SpringBootApplication 表示当前类是 Spring Boot 的入口，Application 类的存放位置必须是其他相关业务类的存放位置的父级。

Spring Boot 整合 JSP

• pom.xml

view code<parent>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-parent</artifactId>
  <version>2.0.7.RELEASE</version>
</parent>

<dependencies>
  <!-- web -->
  <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>

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

• 创建配置文件 application.yml

view codeserver:
  port: 8181
spring:
  mvc:
    view:
      prefix: /
      suffix: .jsp

• 创建 Handler

view codepackage com.oeong.controller;

import com.oeong.entity.Student;
import com.oeong.repository.StudentRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;

@Controller // 返回模型和视图
@RequestMapping("/hello")
public class HelloHandler {

    @Autowired
    private StudentRepository studentRepository;

    @GetMapping("/index")
    public ModelAndView index(){
        ModelAndView modelAndView = new ModelAndView();
        modelAndView.setViewName("index"); // /index.jsp
        modelAndView.addObject("list",studentRepository.findAll());
        return modelAndView;
    }

    @GetMapping("/deleteById/{id}")
    public String deleteById(@PathVariable("id") long id){
        studentRepository.deleteById(id);
        return "redirect:/hello/index";
    }

    @PostMapping("/save")
    public String save(Student student){
        studentRepository.saveOrUpdate(student);
        return "redirect:/hello/index";
    }

    @PostMapping("/update")
    public String update(Student student){
        studentRepository.saveOrUpdate(student);
        return "redirect:/hello/index";
    }

    @GetMapping("/findById/{id}")
    public ModelAndView findById(@PathVariable("id") long id){
        ModelAndView modelAndView = new ModelAndView();
        modelAndView.setViewName("update"); // /update.jsp
        modelAndView.addObject("student",studentRepository.findById(id));
        return modelAndView;
    }
}

• JSP

index.jsp

view code<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ page isELIgnored="false" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
    <h1>学生信息</h1>
    <table>
        <tr>
            <th>学生编号</th>
            <th>学生姓名</th>
            <th>学生年龄</th>
            <th>操作</th>
        </tr>
        <c:forEach items="${list}" var="student">
            <tr>
                <td>${student.id}</td>
                <td>${student.name}</td>
                <td>${student.age}</td>
                <td>
                    <a href="/hello/findById/${student.id}">修改</a>
                    <a href="/hello/deleteById/${student.id}">删除</a>
                </td>
            </tr>
        </c:forEach>
    </table>
    <a href="/save.jsp">添加学生</a>
</body>
</html>

save.jsp

view code<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
    <form action="/hello/save" method="post">
        ID:<input type="text" name="id"/><br/>
        name:<input type="text" name="name"/><br/>
        age:<input type="text" name="age"/><br/>
        <input type="submit" value="提交"/>
    </form>
</body>
</html>

update.jsp

view code<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
    <form action="/hello/update" method="post">
        ID:<input type="text" name="id" value="${student.id}" readonly/><br/>
        name:<input type="text" name="name" value="${student.name}"/><br/>
        age:<input type="text" name="age" value="${student.age}"/><br/>
        <input type="submit" value="提交"/>
    </form>
</body>
</html>

Spring Boot 整合 HTML

Spring Boot 可以结合 Thymeleaf 模版来整合 HTML，使用原生的 HTML 作为视图。

Thymeleaf 模版是面向 Web 和独立环境的 Java 模版引擎，能够处理 XML、HTML、JavaScript、CSS 等。

view code<p th:text="${message}"></p>

• pom.xml

view code<!-- 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>

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

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

• appliction.yml

view codeserver:
  port: 8181
spring:
  thymeleaf:
    prefix: classpath:/templates/
    suffix: .html
    mode: HTML5
    encoding: UTF-8

• Handler

view codepackage com.oeong.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
@RequestMapping("/index")
public class IndexHandler {

    @GetMapping("/index")
    public String index(){
        System.out.println("index...");
        return "index";
    }
}

• HTML resource/templates/index.html

view code<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <h1>Hello World</h1>
</body>
</html>

如果希望客户端可以直接访问 HTML 资源，将这些资源放置在 static 路径下即可，否则必须通过 Handler 的后台映射才可以访问静态资源。

Thymeleaf 常用语法

赋值、拼接

view code@GetMapping("/index2")
public String index2(Map<String,String> map){
  map.put("name","张三");
  return "index";
}

view code<p th:text="${name}"></p>
<p th:text="'学生姓名是'+${name}+2"></p>
<p th:text="|学生姓名是,${name}|"></p>

条件判断：if/unless

th:if 表示条件成立时显示内容，th:unless 表示条件不成立时显示内容

view code@GetMapping("/if")
public String index3(Map<String,Boolean> map){
    map.put("flag",true);
    return "index";
}

view code<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>

循环

view code@GetMapping("/index")
public String index(Model model){
    System.out.println("index...");
    List<Student> list = new ArrayList<>();
    list.add(new Student(1L,"张三",22));
    list.add(new Student(2L,"李四",23));
    list.add(new Student(3L,"王五",24));
    model.addAttribute("list",list);
    return "index";
}

view code<table>
  <tr>
    <th>index</th>
    <th>count</th>
    <th>学生ID</th>
    <th>学生姓名</th>
    <th>学生年龄</th>
  </tr>
  <tr th:each="student,stat:${list}" th:style="'background-color:'+@{${stat.odd}?'#F2F2F2'}">
    <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>
</table>

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

Thymeleaf 对于 URL 的处理是通过 @{...} 进行处理，结合 th:href 、th:src

view code<a th:href="@{http://www.baidu.com}">跳转</a>
<a th:href="@{http://localhost:8181/index/url/{na}(na=${name})}">跳转2</a>
<img th:src="${src}">
<div th:style="'background:url('+ @{${src}} +');'"><br/><br/><br/></div>

三元运算

view code@GetMapping("/eq")
public String eq(Model model) {
    model.addAttribute("age",30);
    return "test";
}

view code<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

view code@GetMapping("/switch")
public String switchTest(Model model){
    model.addAttribute("gender","女");
    return "test";
}

view code<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

• #ctx ：context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

view code@GetMapping("/object")
public String object(HttpServletRequest request){
    request.setAttribute("request","request对象");
    request.getSession().setAttribute("session","session对象");
    return "test";
}

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

内嵌对象

可以直接通过 # 访问。

1、dates：java.util.Date 的功能方法

2、calendars：java.util.Calendar 的功能方法

3、numbers：格式化数字

4、strings：java.lang.String 的功能方法

5、objects：Object 的功能方法

6、bools：对布尔求值的方法

7、arrays：操作数组的功能方法

8、lists：操作集合的功能方法

9、sets：操作集合的功能方法

10、maps：操作集合的功能方法

view code@GetMapping("/util")
public String util(Model model){
    model.addAttribute("name","zhangsan");
    model.addAttribute("users",new ArrayList<>());
    model.addAttribute("count",22);
    model.addAttribute("date",new Date());
    return "test";
}

view code<!-- 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>

Spring Boot 数据校验

view codepackage com.oeong.entity;

import lombok.Data;
import org.hibernate.validator.constraints.Length;

import javax.validation.constraints.Min;
import javax.validation.constraints.NotEmpty;
import javax.validation.constraints.NotNull;

@Data
public class User {
    @NotNull(message = "id不能为空")
    private Long id;
    @NotEmpty(message = "姓名不能为空")
    @Length(min = 2,message = "姓名长度不能小于2位")
    private String name;
    @Min(value = 16,message = "年龄必须大于16岁")
    private int age;
}

view code@GetMapping("/validator")
public void validatorUser(@Valid User user,BindingResult bindingResult){
  System.out.println(user);
  if(bindingResult.hasErrors()){
    List<ObjectError> list = bindingResult.getAllErrors();
    for(ObjectError objectError:list){
      System.out.println(objectError.getCode()+"-"+objectError.getDefaultMessage());
    }
  }
}

Spring Boot 整合 JDBC

• pom.xml

view code<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>

• application.yml

view codeserver:
  port: 9090
spring:
  thymeleaf:
    prefix: classpath:/templates/
    suffix: .html
    mode: HTML5
    encoding: UTF-8
  datasource:
    url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8
    username: root
    password: root
    driver-class-name: com.mysql.cj.jdbc.Driver

• User

view codepackage com.oeong.entity;

import lombok.Data;
import org.hibernate.validator.constraints.Length;

import javax.validation.constraints.Min;
import javax.validation.constraints.NotEmpty;
import javax.validation.constraints.NotNull;

@Data
public class User {
    @NotNull(message = "id不能为空")
    private Long id;
    @NotEmpty(message = "姓名不能为空")
    @Length(min = 2,message = "姓名长度不能小于2位")
    private String name;
    @Min(value = 60,message = "成绩必须大于60分")
    private double score;
}

• UserRepository

view codepackage com.oeong.repository;

import com.oeong.entity.User;

import java.util.List;

public interface UserRepository {
    public List<User> findAll();
    public User findById(long id);
    public void save(User user);
    public void update(User user);
    public void deleteById(long id);
}

• UserRepositoryImpl

view codepackage com.oeong.repository.impl;

import com.oeong.entity.User;
import com.oeong.repository.UserRepository;
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;

    @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(name,score) values(?,?)",user.getName(),user.getScore());
    }

    @Override
    public void update(User user) {
        jdbcTemplate.update("update user set name = ?,score = ? where id = ?",user.getName(),user.getScore(),user.getId());
    }

    @Override
    public void deleteById(long id) {
        jdbcTemplate.update("delete from user where id = ?",id);
    }
}

• Handler

view codepackage com.oeong.controller;

import com.oeong.entity.User;
import com.oeong.repository.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
@RequestMapping("/user")
public class UserHandler {

    @Autowired
    private UserRepository userRepository;

    @GetMapping("/findAll")
    public List<User> findAll(){
        return userRepository.findAll();
    }

    @GetMapping("/findById/{id}")
    public User findById(@PathVariable("id") long id){
        return userRepository.findById(id);
    }

    @PostMapping("/save")
    public void save(@RequestBody User user){
        userRepository.save(user);
    }

    @PutMapping("/update")
    public void update(@RequestBody User user){
        userRepository.update(user);
    }

    @DeleteMapping("/deleteById/{id}")
    public void deleteById(@PathVariable("id") long id){
        userRepository.deleteById(id);
    }
}

Spring Boot 整合 MyBatis

MyBatis 是一款优秀的持久层框架，它支持定制化 SQL、存储过程以及高级映射。MyBatis 避免了几乎所有的 JDBC 代码和手动设置参数以及获取结果集。MyBatis 可以使用简单的 XML 或注解来配置和映射原生信息，将接口和 Java 的 POJOs(Plain Ordinary Java Object,普通的 Java对象)映射成数据库中的记录。

特点：

view code1. 解除sql与程序代码的耦合，提高可维护性

2. 提供xml标签，支持编写动态sql

1、创建Maven工程，pom.xml

view code<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-parent</artifactId>
    <version>2.4.5</version>
</parent>
<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
        <version>2.1.4</version>
        <!-- mybatis自己出的版本，而不是spring框架自带的 -->
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>8.0.23</version>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
    </dependency>
</dependencies>

groupId和artifactId被统称为“坐标”，目的是保证项目唯一性
groupId：包结构，例如com.oeong（域名.公司名）
artifactId：项目名，例如CQCQ

2、创建数据表

view codecreate database test;
use test;
create table student(
    id int primary key auto_increment,
    name varchar(11),
    score double,
    birthday date
);

3、创建Student实体类

view codepackage com.oeong.entity;

import lombok.Data;

import java.util.Date;

@Data
public class Student {
    private Long id;
    private String name;
    private Double score;
    private Date birthday;
}

4、创建StudentRepository接口

view codepackage com.oeong.repository;

import com.oeong.entity.Student;
import org.springframework.stereotype.Repository;

import java.util.List;
@Repository
public interface StudentRepository {
    public void save(Student student);
    public void update(Student student);
    public void deleteById(Long id);
    public List<Student> findAll();
    public Student findById(Long id);
}

5、在resources/mapping路径下创建StudentRepository接口对应的Mapper.xml（半自动化）

view code<?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.oeong.repository.StudentRepository">
    <insert id="save" parameterType="Student">
        insert into student(name, score, birthday)
        values(#{name}, #{score}, #{birthday})
    </insert>
    <delete id="deleteById" parameterType="Long">
        delete * from student where id=#{id}
    </delete>
    <update id="update" parameterType="Student">
        update student set name=#{name}, score=#{score},
        birthday=#{birthday} where id=#{id}
    </update>
    <select id="findById" parameterType="Long" resultType="Student">
        select * from student where id=#{id}
    </select>
    <select id="findAll" resultType="Student">
        select * from student
    </select>
</mapper>

6、创建StudentHandler，注入StudentRepository

controller是控制器，handler是控制器的处理器方法

view codepackage com.oeong.controller;

import com.oeong.entity.Student;
import com.oeong.repository.StudentRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
public class StudentHandler {
    
    @Autowired
    private StudentRepository studentRepository;
    // 在mapper文件上加@Repository注解，这是从spring2.0新增的一个注解，用于简化 Spring 的开发，实现数据访问

    @PutMapping("/save")
    public void save(@RequestBody Student student) {
        studentRepository.save(student);
    }
	// @RequestBody：把Json数据转成Java对象
    // @ResponceBody：把Java对象转成Json数据
    
    @DeleteMapping("/delete/{id}")
    public void deleteById(@PathVariable("id") Long id) {
        studentRepository.deleteById(id);
    }

    @PostMapping("/update")
    public void update(@RequestBody Student student) {
        studentRepository.update(student);
    }

    @GetMapping("/findAll")
    public List<Student> findAll() {
        return studentRepository.findAll();
    }

    @GetMapping("/findById/{id}")
    public Student findById(@PathVariable("id") Long id) {
        return studentRepository.findById(id);
    }
}

7、application.yml

view codespring:
  datasource:
    url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8
    username: root
    password: root
    driver-class-name: com.mysql.cj.jdbc.Driver
mybatis:
  mapper-locations: classpath:/mapping/*.xml
  type-aliases-package: com.oeong.entity # 提取包名

8、创建Application启动

view codepackage com.oeong;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
@MapperScan("com.oeong.repository") // 将spring提供的Mapper扫到IOC中
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

Spring Boot 整合 Spring Data JPA

JPA(Java Persistence API)，即Java持久层API，是JDK 5.0注解或XML描述对象－关系表的映射关系，并将运行期的实体对象持久化到数据库中。

JPA是一种规范，也即JPA仅仅定义了一些接口，而接口是需要实现才能工作的。所以底层需要某种实现，而Hibernate就是实现了JPA接口的ORM框架。

Hibernate 框架是对JPA规范的实现；Spring Data JPA 不是对JPA规范的具体实现，而是再次封装抽象，底层还是使用 Hibernate 实现。

1、pom.xml

view code<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-parent</artifactId>
    <version>2.4.5</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-data-jpa</artifactId>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>8.0.23</version>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
    </dependency>
</dependencies>

2、Student实体类

view codepackage oeong.entity;

import lombok.Data;

import javax.persistence.*;
import java.util.Date;

@Data
@Entity // 与数据表映射
public class Student {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY) // 生成策略
    private Long id;
    @Column
    private String name;
    @Column
    private Double score;
    @Column
    private Date birthday;
}

3、创建StudentRepository接口，全自动

view codepackage oeong.entity;

import org.springframework.data.jpa.repository.JpaRepository;

public interface StudentRepository extends JpaRepository<Student, Long> {
}

4、创建StudentHandler，注入StudentRepository

view codepackage com.oeong.controller;

import com.oeong.entity.Student;
import com.oeong.repository.StudentRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
public class StudentHandler {

    @Autowired
    private StudentRepository studentRepository;

    @PutMapping("/save")
    public void save(@RequestBody Student student) {
        studentRepository.save(student);
    }

    @DeleteMapping("/deleteById/{id}")
    public void deleteById(@PathVariable("id") Long id) {
        studentRepository.deleteById(id);
    }

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

    @GetMapping("/findAll")
    public List<Student> findAll() {
        return studentRepository.findAll();
    }

    @GetMapping("/findById/{id}")
    public Student findById(@PathVariable("id") Long id) {
        return studentRepository.findById(id).get();
    }
}

5、application.yml

view codespring:
  datasource:
    url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8
    username: root
    password: root
    driver-class-name: com.mysql.cj.jdbc.Driver
  jpa:
    show-sql: true # 显示sql语句
    properties:
      hibernate:
        format_sql: true # 格式化
server:
  port: 8181

6、启动类Application

view codepackage com.oeong;

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);
    }
}

Spring Boot 整合 Spring Data Redis

Redis（Remote Dictionary Server )，即远程字典服务，是一个基于内存、分布式的key-value 存储数据库。

• Redis启动

打开一个cmd窗口，使用cd命令切换目录到 redis目录运行：

view coderedis-server.exe redis.windows.conf

此时另启一个 cmd 窗口，运行

view coderedis-cli.exe -h 127.0.0.1 -p 6379

1、创建Maven工程，pom.xml

view code<parent>
    <artifactId>spring-boot-parent</artifactId>
    <groupId>org.springframework.boot</groupId>
    <version>2.4.5</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-data-redis</artifactId>
    </dependency>
    <dependency>
        <groupId>org.apache.commons</groupId>
        <artifactId>commons-pool2</artifactId>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
    </dependency>
</dependencies>

2、创建实体类

view codepackage com.oeong.entity;

import lombok.Data;

import java.io.Serializable;
import java.util.Date;

@Data
public class Student implements Serializable {
    private Long id;
    private String name;
    private Double score;
    private Date birthday;
}

3、创建StudentHandler

view codepackage com.oeong.controller;

import com.oeong.entity.Student;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.web.bind.annotation.*;

@RestController
public class StudentHandler {

    @Autowired
    private RedisTemplate redisTemplate;

    @PostMapping("/set/{key}")
    public void set(@RequestBody Student student,
                    @PathVariable("key") String key) {
        redisTemplate.opsForValue().set(key, student);
    }

    @GetMapping("/get/{key}")
    public Student get(@PathVariable("key") String key) {
        return (Student) redisTemplate.opsForValue().get(key);
    }

    @DeleteMapping("/delete/{key}")
    public boolean delete(@PathVariable("key") String key) {
        redisTemplate.delete(key);
        return redisTemplate.hasKey(key);
    }
}

4、application.yml

view codespring:
  redis:
    database: 0
    host: localhost
    port: 6379
server:
  port: 8181

5、启动类Application

view codepackage com.oeong;

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);
    }
}

Spring Boot 整合 Spring Security

Spring Security 是一个功能强大且高度可定制的身份验证和访问控制框架。它是用于保护基于Spring的应用程序的实际标准。

1、创建Maven工程，pom.xml

view code<properties>
    <thymeleaf.version>3.0.11</thymeleaf.version>
</properties>

<parent>
    <artifactId>spring-boot-parent</artifactId>
    <groupId>org.springframework.boot</groupId>
    <version>2.4.5</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-security</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-thymeleaf</artifactId>
    </dependency>
</dependencies>
</project>

2、创建Handler

view codepackage com.oeong.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;

@Controller
public class HelloHandler {

    @GetMapping("/index")
    public String index() {
        return "index";
    }
}

3、创建templates/index.html

view code<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <h1>Hello World</h1>
</body>
</html>

4、application.yml

view codespring:
  thymeleaf:
    prefix: classpath:/templates/
    suffix: .html
server:
  port: 8181

5、启动类Application

view codepackage com.oeong;

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);
    }
}

6、设置自定义密码

view codespring:
  thymeleaf:
    prefix: classpath:/templates/
    suffix: .html
  security:
    user:
      name: root
      password: root
server:
  port: 8181

权限管理

定义两个 HTML 资源：index.html、admin.html，同时定义两个⻆⾊ ADMIN 和 USER，ADMIN 拥有访问 index.html 和 admin.html 的权限，USER 只有访问 index.html 的权限。

7、创建SecurityConfig类

view codepackage com.oeong.config;

import com.oeong.config.MyPasswordEncoder.MyPasswordEncoder;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    public void configure(AuthenticationManagerBuilder auth) throws Exception {
        auth.inMemoryAuthentication().passwordEncoder(new MyPasswordEncoder())
                .withUser("user").password(new MyPasswordEncoder().encode("000")).roles("USER")
                .and()
                .withUser("admin").password(new MyPasswordEncoder().encode("123")).roles("ADMIN", "USER");
    }

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.authorizeRequests().antMatchers("/admin").hasRole("ADMIN")
                .antMatchers("/index").access("hasRole('ADMIN') or hasRole('USER')")
                .anyRequest().authenticated()
                .and()
                .formLogin().loginPage("/login").permitAll()
                .and()
                .logout().permitAll()
                .and()
                .csrf().disable();
    }
}

MyPasswordEncoder类

view codepackage com.oeong.config.MyPasswordEncoder;

import org.springframework.security.crypto.password.PasswordEncoder;

public class MyPasswordEncoder implements PasswordEncoder {
    @Override
    public String encode(CharSequence charSequence) {
        return charSequence.toString();
    }

    @Override
    public boolean matches(CharSequence charSequence, String s) {
        return s.equals(charSequence.toString());
    }
}

8、修改Handler

view codepackage com.oeong.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;

@Controller
public class HelloHandler {

    @GetMapping("/index")
    public String index() {
        return "index";
    }

    @GetMapping("/admin")
    public String admin() {
        return "admin";
    }

    @GetMapping("/login")
    public String login() {
        return "login";
    }
}

9、login.html

view code<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>login</title>
</head>
<body>
  <form th:action="@{/login}" method="post">
    用户名：<input type="text" name="username"><br>
    密码：<input type="text" name="password"><br>
    <input type="submit" value="登录">
  </form>
</body>
</html>

10、index.html

view code<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <h1>Hello World</h1>
    <form action="/logout" method="post">
        <input type="submit" value="退出">
    </form>
</body>
</html>

11、admin.html

view code<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>admin</title>
</head>
<body>
    <h1>后台管理系统</h1>
    <form action="/logout" method="post">
        <input type="submit" value="退出">
    </form>
</body>
</html>