一、SpringBoot与SpringDateJPA的整合

1-1、需求

查询数据库---->得到数据------>展示到页面上

1-2、整合步骤

1-2-1、创建SpringBoot工程

具体步骤查看我上一篇随笔

https://www.cnblogs.com/pengpengdeyuan/p/11798804.html

1-2-2、添加maven依赖（pom.xml）

<dependencies>

        <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>

            <exclusions>

                <exclusion>

                    <groupId>org.junit.vintage</groupId>

                    <artifactId>junit-vintage-engine</artifactId>

                </exclusion>

            </exclusions>

        </dependency>

        <!--添加springdatajpa的依赖-->

        <dependency>

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

            <artifactId>spring-boot-starter-data-jpa</artifactId>

        </dependency>

        <!--mysql-->

        <dependency>

            <groupId>mysql</groupId>

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

        </dependency>

        <!--freemarker模板 依赖-->

        <dependency>

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

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

        </dependency>

        <!--Lombok依赖-->

        <dependency>

            <groupId>org.projectlombok</groupId>

            <artifactId>lombok</artifactId>

            <version>1.18.6</version>

        </dependency>

        <!--mybatis-->

        <dependency>

            <groupId>org.mybatis.spring.boot</groupId>

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

            <version>1.1.1</version>

        </dependency>

    </dependencies>

1-2-3、创建MySQL数据表

CREATE TABLE user(

    uid INT PRIMARY KEY AUTO_INCREMENT,

    username VARCHAR(30),

    `password` VARCHAR(10)

);

1-2-4、在配置文件中配置数据库连接

在resources文件夹下创建application配置文件

提供两种配置文件，可任选其一

application.properties：

spring.datasource.driver-class-name=com.mysql.jdbc.Driver

spring.datasource.url=jdbc:mysql://127.0.0.1:3306/user

spring.datasource.username=（自己MySQL的用户名，一般为root）

spring.datasource.password=（自己MySQL的密码）

spring.jpa.database=MySQL

spring.jpa.show-sql=true

spring.jpa.generate-ddl=true

application.yml

spring:

  datasource:

    driverClassName: com.mysql.jdbc.Driver

    url: jdbc:mysql://127.0.0.1:3306/user?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone = GMT

    username: （自己MySQL的用户名，一般为root）

    password: （自己MySQL的密码）

  jpa:

    database: MySQL

    show-sql: true

    generate-ddl: true

1-2-5、创建User实体类对象

@Entity//指定实体类，必须指定@id

@Table(name = "user")//指定表名

@Data//编译后自动生成所有属性的get\set方法、toString方法、hashCode方法、equals方法

@AllArgsConstructor//编译后自动生成全参构造

@NoArgsConstructor//编译后自动生成无参构造

public class User {

    @Id//主键

    @GeneratedValue(strategy = GenerationType.IDENTITY)//自增

    private int uid;

    private String username;

    private String password;

}

1-2-6、创建Controller层

@RestController//相当于@ResponseBody跟@Controller

public class UserController {

    @Autowired

    private UserDao userDao;

    @RequestMapping(value = "/user")

    public List<User> getUser(){

        return userDao.findAll();

    }

}

1-2-7、创建持久化层

public interface UserDao extends JpaRepository<User,Integer> { }

1-2-8、启动项目后浏览器访问

二、SpringBoot与Mybatis的整合

在上一节的基础上，配置Mybatis

2-1、pom.xml文件

<?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 https://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>2.0.7.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.pk</groupId>
    <artifactId>springbootday02</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>springbootday02</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-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <!--添加springdatajpa的依赖-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <!--mysql-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <!--freemarker模板 依赖-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-freemarker</artifactId>
        </dependency>
        <!--Lombok依赖-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.6</version>
        </dependency>
        <!--mybatis-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.1.1</version>
        </dependency>
    </dependencies>

    <build>
        <!--设置Mapper映射可在java或者resources文件夹下-->
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>false</filtering>
            </resource>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.*</include>
                </includes>
                <filtering>false</filtering>
            </resource>
        </resources>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>

    </build>

</project>

2-2、新建一个MyUser实体类

也可以直接用上一节的实体类，注意lombok注解与自己创建的构造器、set、get等方法不能重复

public class MyUser {

    private int uid;

    private String username;

    private String password;

    public MyUser(int uid, String username, String password) {

        this.uid = uid;

        this.username = username;

        this.password = password;

    }

    public MyUser() {

    }

    public int getUid() {

        return uid;

    }

    public void setUid(int uid) {

        this.uid = uid;

    }

    public String getUsername() {

        return username;

    }

    public void setUsername(String username) {

        this.username = username;

    }

    public String getPassword() {

        return password;

    }

    public void setPassword(String password) {

        this.password = password;

    }

    @Override

    public String toString() {

        return "MyUser{" +

                "uid=" + uid +

                ", username='" + username + '\'' +

                ", password='" + password + '\'' +

                '}';

    }

}

2-3、创建Controller层类

@Controller

@RequestMapping("/myuser")

public class MyUserController {

    @Autowired

    private MyUserMapper myUserMapper;

    @RequestMapping(value = "/getMyUserList",method = RequestMethod.GET)

    public String getMyUserList(Model model){

        List<MyUser> userList = myUserMapper.getMyUserList();

        model.addAttribute("userList",userList);

        return "myuser";

    }

}

2-4、创建mapper接口

public interface MyUserMapper {

    List<MyUser> getMyUserList();

}

2-5、创建mapper.xml文件

<?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="MyUserMapper接口的全路径名">

    <select id="getMyUserList" resultType="MyUser实体类的全路径名">

        select * from user

    </select>

</mapper>

2-6、创建模板文件

在resources文件夹下的templates文件夹下创建myuser.ftl文件（Freemarker模板）

<html>

    <head>

        <title>User</title>

    </head>

    <body>

        <table align="center" border="1px" cellpadding="5px" cellspacing="0px">

            <tr>

                <th>ID</th>

                <th>用户名</th>

                <th>密码</th>

            </tr>

            <#list userList as user>

                <tr>

                    <td>${user.uid}</td>

                    <td>${user.username}</td>

                    <td>${user.password}</td>

                </tr>

            </#list>

        </table>

    </body>

</html>

巴特西

SpringBoot与SpringDateJPA和Mybatis的整合