SpringBoot数据访问+Druid+Mybatis操作步骤

朴灿烈づ我的快乐病毒、 2022-08-30 05:18 223阅读 0赞

一、数据访问原始的配置

访问SpringBoot的官网，找到对应的文档，可以查阅相关的starter  
https://docs.spring.io/spring-boot/docs/current/reference/html/using-spring-boot.html\#using-boot-starter  
1、导入JDBC场景

<dependency>  
    <groupId>org.springframework.boot</groupId>  
    <artifactId>spring-boot-starter-data-jdbc</artifactId>  
</dependency>![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NDU4ODI0Mw_size_16_color_FFFFFF_t_70]

数据库的驱动没有导入，需要手动导入：官方不知道想要连接的是哪个数据库，所以没有自动导入  
2、导入MySql的驱动

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NDU4ODI0Mw_size_16_color_FFFFFF_t_70 1]

https://mvnrepository.com/search?q=mysql

<dependency>  
    <groupId>mysql</groupId>  
    <artifactId>mysql-connector-java</artifactId>  
      
</dependency>  
  
其中boot2.4.2中mysql官方仲裁默认的版本号是8.0.22，所以可以省略不写version  
想要修改版本：  
直接以来引入的具体版本（maven的就近依赖原则）  
重新声明版本，在当期那pom的属性里声明版本号，优先当前项目的属性。  
引入了jdbc，必须要配置相关的数据库属性，否则项目启动会报错  
3、配置Mysql的基本属性

spring:  
  datasource:  
    url: jdbc:mysql://localhost:3306/test?serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=utf-8  
    username: root  
    password: root  
    driver-class-name: com.mysql.cj.jdbc.Driver  
  
4、测试

package com.ityj.druid;

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.util.Map;

@SpringBootTest  
class DruidApplicationTests \{

@Autowired  
    private JdbcTemplate jdbcTemplate;

@Autowired  
    private DataSource dataSource;

@Test  
    void contextLoads() \{  
        System.out.println(dataSource.getClass());  
        Map<String, Object> stringObjectMap = jdbcTemplate.queryForMap("select name from person where id = 1");  
        System.out.println("stringObjectMap = " + stringObjectMap);  
    \}

结果：  
class com.zaxxer.hikari.HikariDataSource  
stringObjectMap = \{name=Jack\}

二、使用Druid数据源

https://github.com/alibaba/druid/tree/master/druid-spring-boot-starter  
1、引入druid的starter

<dependency>  
    <groupId>com.alibaba</groupId>  
    <artifactId>druid-spring-boot-starter</artifactId>  
    <version>1.1.17</version>  
</dependency>  
此时不用任何其他操作，结合jdbc的其他配置，即可切换为druid数据源

class com.alibaba.druid.spring.boot.autoconfigure.DruidDataSourceWrapper  
2、配置并使用druid的监控功能

druid:  
      aop-patterns: com.atguigu.admin.\*  \#监控SpringBean  
      filters: stat,wall     \# 底层开启功能，stat（sql监控），wall（防火墙）

stat-view-servlet: \# 配置监控页功能  
        enabled: true  
        login-username: admin  
        login-password: admin  
        resetEnable: true

web-stat-filter: \# 监控web  
        enabled: true  
        urlPattern: /\*  
        exclusions: '\*.js,\*.gif,\*.jpg,\*.png,\*.css,\*.ico,/druid/\*'

filter:  
        stat: \# 对上面filters里面的stat的详细配置  
          slow-sql-millis: 1000  
          logSlowSql: true  
          enabled: true  
        wall:  
          enabled: true  
          config:  
            drop-table-allow: false  
  
三、整合Mybatis

https://github.com/mybatis/spring-boot-starter  
1、引入starter

<dependency>  
    <groupId>org.mybatis.spring.boot</groupId>  
    <artifactId>mybatis-spring-boot-starter</artifactId>  
    <version>2.1.4</version>  
</dependency>  
  
2、配置mybatis的规则

mybatis:  
  \# 制定mybatis全局配置文件的位置  
  config-location: classpath:/mybatis/mybatis-config.xml  
  mapper-locations: classpath:/mybatis/mapper/\*Mapper.xml  
  
3、编写mapper接口，并绑定对应的映射文件

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NDU4ODI0Mw_size_16_color_FFFFFF_t_70 2]

1.mybatis-config.xml编写

<?xml version="1.0" encoding="UTF-8" ?>  
<!DOCTYPE configuration  
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"  
        "http://mybatis.org/dtd/mybatis-3-config.dtd">  
<configuration>  
    <settings>  
        <setting name="logImpl" value="STDOUT\_LOGGING"/>  
    </settings>  
</configuration>  
  
2.实体类Person.java

package com.ityj.druid.entity;

import io.swagger.annotations.ApiModel;  
import io.swagger.annotations.ApiModelProperty;  
import lombok.Data;

import java.util.Date;

@Data  
@ApiModel(value = "Person实体类")  
public class Person \{  
    @ApiModelProperty(value = "主键id")  
    private int id;  
    @ApiModelProperty(value = "姓名")  
    private String name;  
    @ApiModelProperty(value = "年龄")  
    private int age;  
    @ApiModelProperty(value = "生日(eg:1998/12/12 12:12:12)")  
    private Date birthday;  
    @ApiModelProperty(value = "性别")  
    private String gender;  
\}

3.接口PersonMapper.java

package com.ityj.druid.mapper;

import com.ityj.druid.entity.Person;  
import org.apache.ibatis.annotations.Mapper;  
import org.apache.ibatis.annotations.Param;

@Mapper  
public interface PersonMapper \{

Person getPersonById(@Param(value = "id") int id);

4.对应的mapper:PersonMapper.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.ityj.druid.mapper.PersonMapper">  
    <select id="getPersonById" parameterType="int" resultType="com.ityj.druid.entity.Person">  
        select \* from person where id = \#\{id\}  
    </select>  
</mapper>  
  
5.service接口PersonService.java

package com.ityj.druid.service;

import com.ityj.druid.entity.Person;

public interface PersonService \{  
    Person getPersonById(int personId);  
\}  
  
6.service实现类PersonServiceImpl.java

package com.ityj.druid.service.impl;

import com.ityj.druid.entity.Person;  
import com.ityj.druid.mapper.PersonMapper;  
import com.ityj.druid.service.PersonService;  
import org.springframework.beans.factory.annotation.Autowired;  
import org.springframework.stereotype.Service;  
import org.springframework.util.ObjectUtils;

@Service  
public class PersonServiceImpl implements PersonService \{

@Autowired  
    private PersonMapper personMapper;

@Override  
    public Person getPersonById(int personId) \{  
        if (ObjectUtils.isEmpty(personId)) \{  
           return new Person();  
        \}  
        return personMapper.getPersonById(personId);  
    \}  
\}  
  
7.controller控制器编写

package com.ityj.druid.controller;

import com.ityj.druid.service.PersonService;  
import io.swagger.annotations.ApiModel;  
import lombok.extern.slf4j.Slf4j;  
import org.springframework.beans.factory.annotation.Autowired;  
import org.springframework.util.ObjectUtils;  
import org.springframework.web.bind.annotation.RequestMapping;  
import org.springframework.web.bind.annotation.RequestMethod;  
import org.springframework.web.bind.annotation.RequestParam;  
import org.springframework.web.bind.annotation.RestController;

@RestController  
@ApiModel(value = "HelloController测试的控制器入口")  
@Slf4j  
public class HelloController \{

@Autowired  
    private PersonService personService;

@RequestMapping(path = "/getPerson", method = RequestMethod.GET)  
    public Object getPerson(@RequestParam(value = "personId") int personId) \{  
        log.info("进入getPerson()...");  
        if (ObjectUtils.isEmpty(personId)) \{  
            return "请检查入参是否完整！";  
        \}  
        return personService.getPersonById(personId);  
    \}

\}  
  
8.测试

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NDU4ODI0Mw_size_16_color_FFFFFF_t_70 3]

9.完全通过注解实现数据访问  
package com.ityj.druid.mapper;

import com.ityj.druid.entity.Person;  
import org.apache.ibatis.annotations.Mapper;  
import org.apache.ibatis.annotations.Param;  
import org.apache.ibatis.annotations.Select;

import java.util.List;

@Mapper  
public interface PersonMapper \{

@Select(value = "select \* from person where 1 = 1")  
    List<Person> getAllPerson();

总结：  
  1. 引入mabatis-starter  
  2. 配置application.yml中指定config-location和mapper-locations的位置  
  3. 编写mapper接口并标注@Mapper注解  
  4. 简单方法可以在接口上写@Select注解编写  
  5. 复杂方法编写mapper.xml进行绑定映射  
  6. @Mapper注解标注的类会被自动扫描；项目启动类上标注@MapperScan("com.ityj.druid.mapper")可以批量扫描，无需每个类上标注@Mapper注解

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