SpringBoot整合数据库

必须导入的依赖：

<!--mysql驱动-->
<dependency>
    <groupId>com.mysql</groupId>
    <artifactId>mysql-connector-j</artifactId>
    <version>8.0.32</version>
</dependency>

如果用mybatis的话就用

<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.1.2</version>
</dependency>

如果是自己实现的话就用jdbc的依赖

配置数据库的信息

spring.datasource.username=root
spring.datasource.password=root
spring.datasource.url= jdbc:mysql://localhost:3306/boot
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

将上述的配置整合后SpringBoot就会自动生成DataSource类，就可以直接用

springBoot集成jdbc的所有属性方法（源码中JdbcTemplate类）

public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
    private static final String RETURN_RESULT_SET_PREFIX = "#result-set-";
    private static final String RETURN_UPDATE_COUNT_PREFIX = "#update-count-";
    private boolean ignoreWarnings = true;
    private int fetchSize = -1;
    private int maxRows = -1;
    private int queryTimeout = -1;
    private boolean skipResultsProcessing = false;
    private boolean skipUndeclaredResults = false;
    private boolean resultsMapCaseInsensitive = false;

    public JdbcTemplate() {
    }

相关功能就可以通过jdbcTemplate实现

通过原生的JDBC查询数据

@RestController
public class JDBCController {

    @Autowired
    JdbcTemplate jdbcTemplate;

    @RequestMapping("/test01")
    public String testJDBC(){
        String sql = "select * from employee";
        List<Map<String, Object>> maps = jdbcTemplate.queryForList(sql);
        for (Map map : maps){
            System.out.println(map);
        }
        return "maps";
    }
}

配置信息

在springBoot的application.properties文件中

mybatis.mapper-locations=classpath:com.demo.mapper/*.xml
mybatis.type-aliases-package=com.demo.pojo
# 开启下划线与驼峰命名的转换
mybatis.configuration.map-underscore-to-camel-case=true

SpringBoot整合MyBatis

连接信息及其相关依赖

<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.1.2</version>
</dependency>


  <!--mysql驱动-->
  <dependency>
      <groupId>com.mysql</groupId>
      <artifactId>mysql-connector-j</artifactId>
      <version>8.0.32</version>
  </dependency>

逆向工程驱动

<plugin>
    <groupId>org.mybatis.generator</groupId>
    <artifactId>mybatis-generator-maven-plugin</artifactId>
    <version>1.3.2</version>
    <configuration>
        <verbose>true</verbose>
        <overwrite>true</overwrite>
    </configuration>
</plugin>

逆向工程配置文件

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE generatorConfiguration
        PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
        "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">
<generatorConfiguration>
    <!--
targetRuntime: 执行生成的逆向工程的版本
    MyBatis3Simple: 生成基本的CRUD（简洁版）
    MyBatis3: 生成带条件的CRUD（终极版）
-->
<!--数据库本地jar包-->
    <classPathEntry location="D:\lib\mysql-connector-java-8.0.29.jar"/>
    <context id="DB2Tables" targetRuntime="MyBatis3Simple">
        <property name="javaFileEncoding" value="UTF-8"/>

        <!--suppressAllComments 设置为true 则不再生成注释-->
        <commentGenerator>
            <property name="suppressAllComments" value="true" />
        </commentGenerator>


        <!-- 数据库的连接信息 -->
        <jdbcConnection driverClass="com.mysql.cj.jdbc.Driver"
                        connectionURL="jdbc:mysql://localhost:3306/boot"
                        userId="root"
                        password="root">
        </jdbcConnection>
        <javaTypeResolver>
            <property name="forceBigDecimals" value="false"/>
        </javaTypeResolver>

        <!-- javaBean : 数据库表对应的实体类-->
        <javaModelGenerator targetPackage="com.demo.pojo" targetProject=".\src\main\java">
            <property name="enableSubPackages" value="true" />
            <property name="trimStrings" value="true" />
        </javaModelGenerator>

        <!-- SQL映射文件 : 与Mapper接口对应  -->
        <sqlMapGenerator targetPackage="com.demo.mapper" targetProject=".\src\main\resources">
            <property name="enableSubPackages" value="true" />
        </sqlMapGenerator>


        <!-- Mapper接口 :实现相关功能的接口 -->
        <javaClientGenerator type="XMLMAPPER"
                             targetPackage="com.demo.mapper" targetProject=".\src\main\java">
            <property name="enableSubPackages" value="true" />
        </javaClientGenerator>

        <!-- 逆向工程的表 与 需要创建的类名 -->
        <!-- tableName 设置为*号，可以对应所有表，此时可以不写domainObjectName -->
        <!-- domainObjectName属性指定 生成出来的实体类的类名 -->
        <table tableName="employee" domainObjectName="employee"/>
    </context>
</generatorConfiguration>