SpringBoot整合MyBatis

SpringBoot整合MyBatis

系統要求

Java 8+

springBoot2.5 +

創建springBoot項目工程

導入依賴

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

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
        <scope>runtime</scope>
        <optional>true</optional>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-jdbc</artifactId>
    </dependency>
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid</artifactId>
        <version>1.2.6</version>
    </dependency>
    <dependency>
        <groupId>log4j</groupId>
        <artifactId>log4j</artifactId>
        <version>1.2.17</version>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <scope>runtime</scope>
    </dependency>
    <!--Druid starter-->
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid-spring-boot-starter</artifactId>
        <version>1.1.22</version>
    </dependency>
    <dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
        <version>2.2.0</version>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
</dependencies>

項目結構目錄

配置application.yaml

spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3307/webapp1?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
    username: webapp1
    password: webapp1
    type: com.alibaba.druid.pool.DruidDataSource

    #Spring Boot 默認是不注入這些屬性值的，需要自己綁定
    #druid 數據源專有配置
    # 初始化大小，最小，最大
    initialSize: 5
    minIdle: 5
    maxActive: 200
    # 配置獲取連接等待超時的時間
    maxWait: 60000
    # 配置間隔多久才進行一次檢測，檢測需要關閉的空閑連接，單位是毫秒
    timeBetweenEvictionRunsMillis: 60000
    # 配置一個連接在池中最小生存的時間，單位是毫秒
    minEvictableIdleTimeMillis: 300000
    # 用來檢測連接是否有效的sql，要求是一個查詢語句
    validationQuery: SELECT 1 FROM DUAL
    # 建議配置為true，不影響性能，並且保證安全性。申請連接的時候檢測，如果空閑時間大於timeBetweenEvictionRunsMillis，執行validationQuery檢測連接是否有效。
    testWhileIdle: true
    # 申請連接時執行validationQuery檢測連接是否有效，做了這個配置會降低性能
    testOnBorrow: false
    # 歸還連接時執行validationQuery檢測連接是否有效，做了這個配置會降低性能。
    testOnReturn: false
    # 是否緩存preparedStatement，也就是PSCache。PSCache對支持游標的數據庫性能提升巨大，比如說oracle。在mysql下建議關閉。
    poolPreparedStatements: true
    # 要啟用PSCache，必須配置大於0，當大於0時，poolPreparedStatements自動觸發修改為true。
    max-pool-prepared-statement-per-connection-size: 50

    #配置監控統計攔截的filters，stat:監控統計、log4j：日志記錄、wall：防御sql注入
    #如果允許時報錯  java.lang.ClassNotFoundException: org.apache.log4j.Priority
    #則導入 log4j 依賴即可，Maven 地址：https://mvnrepository.com/artifact/log4j/log4j
    filters: stat,wall,log4j
    # 合並多個DruidDataSource的監控數據
    useGlobalDataSourceStat: true
    # 通過connectProperties屬性來打開mergeSql功能；慢SQL記錄
    connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500

mybatis:
  #sql映射文件的位置
#  mapper-locations: classpath:com/xiang/mapper/*.xml
  mapper-locations: classpath:mapper/*.xml
  #開啟駝峰命名轉化
  configuration:
    map-underscore-to-camel-case: true
  #開啟別名
  type-aliases-package: com.xiang

創建User類

package com.xiang.pojo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.springframework.stereotype.Component;

import java.util.Date;

/**
 * Created by IntelliJ IDEA.
 * User: xiang
 * Date: 2021/10/17 23:52
 */
@Component
@Data
@NoArgsConstructor
@AllArgsConstructor
public class User {
    private int id;
    private String username;
    private String age;
    private Date birthday;
}

創建UserMapper

package com.xiang.mapper;

import com.xiang.pojo.User;
import org.apache.ibatis.annotations.Mapper;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.stereotype.Repository;

import java.util.List;

/**
 * Created by IntelliJ IDEA.
 * User: xiang
 * Date: 2021/10/17 23:54
 */
@Mapper
@Repository
public interface UserMapper {
    User findById(int id);

    List<User> findAll();
}

創建UserMapper.xml

<?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.xiang.mapper.UserMapper">

    <select id="findById" resultType="user">
        select * from user where id = #{id}
    </select>
    <select id="findAll" resultType="user">
        select * from user
    </select>

</mapper>

創建UserService

package com.xiang.service;

import com.xiang.pojo.User;

import java.util.List;

/**
 * Created by IntelliJ IDEA.
 * User: xiang
 * Date: 2021/10/18 15:01
 */
public interface UserService {
    User findById(int id);
    List<User> findAll();
}

創建UserServiceImpl

package com.xiang.service.impl;

import com.xiang.mapper.UserMapper;
import com.xiang.pojo.User;
import com.xiang.service.UserService;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.stereotype.Service;

import java.util.List;

/**
 * Created by IntelliJ IDEA.
 * User: xiang
 * Date: 2021/10/18 15:02
 */
@Service

public class UserServiceImpl implements UserService {
    @Autowired
    private UserMapper userMapper;

    @Override
    public User findById(int id) {
        return userMapper.findById(id);

    }

    @Override
    public List<User> findAll() {
        return userMapper.findAll();
    }


}

運行測試

package com.xiang;

import com.alibaba.druid.pool.DruidDataSource;
import com.xiang.pojo.User;
import com.xiang.service.impl.UserServiceImpl;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.jdbc.core.JdbcTemplate;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.List;
import java.util.Map;

@SpringBootTest
class SpringBootDatabaseApplicationTests {
    @Autowired
    UserServiceImpl userService;

    /***
     * 根據id查
     */
    @Test
    public  void  findById(){
        User user = userService.findById(1);
        System.out.println(user);
    }

    /**
     * 查所有
     */
    @Test
    public  void  findAll(){
        System.out.println(userService.findAll());
        System.out.println("/*******************************************/");
        List<User> userList = userService.findAll();
        for (User user : userList) {
            System.out.println(user);
        }
    }
}

測試運行結果

創建UserController

package com.xiang.controller;

import com.xiang.pojo.User;
import com.xiang.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;

/**
 * Created by IntelliJ IDEA.
 * User: xiang
 * Date: 2021/10/18 22:03
 */
@Controller
public class UserController {
    @Autowired
    UserService userService;

    @RequestMapping("findById")
    @ResponseBody
    public String findById(@RequestParam("id") int id) {
        User byId = userService.findById(id);
        return byId.toString();
    }
}

前端運行結果