SpringBoot原理分析 | Spring Data整合：JDBC、Druid、Mybatis

╰半夏微凉° 2024-04-22 19:01 3阅读 0赞

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### Spring Data ###

> Spring Data是一个用于简化数据库访问和操作的开源框架，为开发人员提供了一种通用的方式来处理不同类型的数据存储，例如关系型数据库（如MySQL、PostgreSQL、Oracle）和非关系型数据库（如MongoDB、Cassandra、Redis）等。Spring Data还提供了许多有用的特性和工具，例如数据持久化、事务管理、查询和分页等功能，以及对多种数据访问技术的支持，如JPA、Hibernate、MyBatis等
> 
> Spring Data框架的核心思想是通过使用Repository模式，将数据访问逻辑从业务逻辑中分离出来，从而简化应用程序的开发和维护；开发人员只需要定义一个接口，继承Spring Data提供的Repository接口，即可获得许多常用的数据库操作方法，如增删改查、分页查询等；Spring Data框架会根据接口定义动态生成实现类，从而使得开发人员可以专注于业务逻辑的实现，而不用关注底层的数据访问细节
> 
> Spring Data是一个非常强大和灵活的数据访问框架，可以帮助开发人员更加高效地访问和操作各种类型的数据存储，同时提供了许多有用的特性和工具，能够大大简化应用程序的开发和维护

#### 整合JDBC ####

> JDBC是Java语言中用于与关系型数据库交互的一种标准API；通过JDBC，Java程序可以连接到不同的数据库系统，如MySQL、Oracle、PostgreSQL等，并进行数据的增、删、改、查等操作
> 
> JDBC API包括两部分：JDBC驱动程序和Java应用程序接口。JDBC驱动程序是连接Java应用程序和数据库的桥梁，它们负责与数据库进行通信，并将数据转换为Java程序可以理解的格式。Java应用程序接口则是Java程序访问数据库的核心，它提供了一组标准的类和方法，用于与数据库进行交互

>  *  resources文件夹下创建application.yml文件
> 
>     spring:
>       datasource:
>         username: "root"
>         password: "root"
>         url: jdbc:mysql://localhost:3306/mybatis?useUnicode=true&characterEncoding=utf-8&serverTimezone=UTC
>         driver-class-name: com.mysql.cj.jdbc.Driver
> 
>  *  编写controller层，测试数据库CURD功能
> 
>     package com.wei.controller;
>     
>     import org.springframework.beans.factory.annotation.Autowired;
>     import org.springframework.jdbc.core.JdbcTemplate;
>     import org.springframework.web.bind.annotation.GetMapping;
>     import org.springframework.web.bind.annotation.PathVariable;
>     import org.springframework.web.bind.annotation.RestController;
>     
>     import java.util.List;
>     import java.util.Map;
>     
>     @RestController
>     public class JDBCController {
>          
>     
>         @Autowired(required = false)
>         JdbcTemplate jdbcTemplate;
>     
>         //查询数据库所有信息
>         @GetMapping("/userList")
>         public List<Map<String, Object>> userList() {
>          
>             String sql = "select * from mybatis.user";
>             List<Map<String, Object>> List_maps = jdbcTemplate.queryForList(sql);
>             return List_maps;
>         }
>     
>     
>         @GetMapping("/addUser")
>         public String addUser() {
>          
>             String sql = "insert into mybatis.user(id,name,pwd) values(5,'bbb',520)";
>             jdbcTemplate.update(sql);
>             return "update-ok";
>         }
>     
>         @GetMapping("/updateUser/{id}")
>         public String updateUser(@PathVariable int id) {
>          
>             String sql = "update mybatis.user set name=?,pwd=? where id=" + id;
>     
>             //封装
>             Object[] objects = new Object[2];
>             objects[0] = "qqq";
>             objects[1] = "www";
>     
>             jdbcTemplate.update(sql,objects);
>             return "update-ok";
>         }
>     
>         @GetMapping("/deleteUser/{id}")
>         public String deleteUser(@PathVariable int id) {
>          
>             String sql = "delete from mybatis.user where id = ?";
>             jdbcTemplate.update(sql,id);
>             return "delete-ok";
>         }
>     }

#### 整合Druid ####

> Druid是一个开源的高性能、高可靠性的分布式列存储系统，主要用于支持实时数据探索和分析；提供了一种可扩展的、快速的、实时的数据存储和查询技术，支持高吞吐量和低延迟的查询，并能够处理大规模数据的实时流式处理。Druid的数据存储方式基于列存储，具有高效的压缩算法和索引机制，能够提供高效的数据查询和聚合操作
> 
> Druid的架构包括数据源、数据处理和数据查询三个组件。数据源负责数据的采集和预处理，数据处理组件将数据转换为Druid的列存储格式，并进行索引和压缩，数据查询组件则提供了一个SQL查询引擎和RESTful API，用于查询和聚合存储在Druid中的数据；被广泛用于实时数据分析和探索领域，如广告分析、在线推荐、监控和运营等

>  *  application.yml
> 
>     spring:
>       datasource:
>         username: "root"
>         password: "root"
>         url: jdbc:mysql://localhost:3306/mybatis?useUnicode=true&characterEncoding=utf-8&serverTimezone=UTC
>         driver-class-name: com.mysql.cj.jdbc.Driver
>         #切换数据源
>         type: com.alibaba.druid.pool.DruidDataSource
>     
>         #Spring Boot 默认是不注入这些属性值的，需要自己绑定
>         #druid 数据源专有配置
>         initialSize: 5
>         minIdle: 5
>         maxActive: 20
>         maxWait: 60000
>         timeBetweenEvictionRunsMillis: 60000
>         minEvictableIdleTimeMillis: 300000
>         validationQuery: SELECT 1 FROM DUAL
>         testWhileIdle: true
>         testOnBorrow: false
>         testOnReturn: false
>         poolPreparedStatements: true
>         #配置监控统计拦截的filters，stat:监控统计、log4j：日志记录、wall：防御sql注入
>         #如果允许时报错  java.lang.ClassNotFoundException: org.apache.log4j.Priority
>         #则导入 log4j 依赖即可，Maven 地址：https://mvnrepository.com/artifact/log4j/log4j
>         filters: stat,wall,log4j
>         maxPoolPreparedStatementPerConnectionSize: 20
>         useGlobalDataSourceStat: true
>         connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500
> 
>  *  controller层编写DruidController
> 
>     package com.wei.config;
>     
>     import com.alibaba.druid.pool.DruidDataSource;
>     import com.alibaba.druid.support.http.StatViewServlet;
>     import com.alibaba.druid.support.http.WebStatFilter;
>     import org.springframework.boot.context.properties.ConfigurationProperties;
>     import org.springframework.boot.web.servlet.FilterRegistrationBean;
>     import org.springframework.boot.web.servlet.ServletRegistrationBean;
>     import org.springframework.context.annotation.Bean;
>     import org.springframework.context.annotation.Configuration;
>     
>     import javax.servlet.Filter;
>     import javax.servlet.annotation.WebFilter;
>     import javax.sql.DataSource;
>     import java.util.HashMap;
>     import java.util.Map;
>     
>     @Configuration
>     public class DruidConfig {
>          
>         @ConfigurationProperties(prefix = "spring.datasource")
>         @Bean
>         public DataSource druidDataSource(){
>          
>             return new DruidDataSource();
>         }
>     
>         //后台监控功能
>         @Bean
>         public ServletRegistrationBean StatViewServlet(){
>          
>             ServletRegistrationBean<StatViewServlet> bean = new ServletRegistrationBean<>(new StatViewServlet(), "/druid/*");
>             //后台账号密码
>             HashMap<String, String> initParameters = new HashMap<>();
>             //添加配置
>             initParameters.put("loginUsername","admin");
>             initParameters.put("loginPassword","123456");
>             //允许用户访问
>             initParameters.put("allow","");
>             //禁止用户访问
>             /*initParameters.put("","");*/
>             bean.setInitParameters(initParameters);   //设置初始化参数
>             return bean;
>         }
>     
>         //过滤器Filter
>         @Bean
>         public FilterRegistrationBean webStartFilter(){
>          
>             FilterRegistrationBean<Filter> bean = new FilterRegistrationBean<>();
>             bean.setFilter(new WebStatFilter());
>             //通过请求
>             HashMap<Object, Object> initParameters = new HashMap<>();
>             initParameters.put("exclusions","*.js,*.css,/druid/*");
>             return bean;
>         }
>     }

#### 整合Mybatis ####

>  *  springboot-mybatis依赖
> 
>     
>             <dependency>
>                 <groupId>org.mybatis.spring.boot</groupId>
>                 <artifactId>mybatis-spring-boot-starter</artifactId>
>                 <version>3.0.1</version>
>             </dependency>
> 
>  *  配置数据库连接application.properties
> 
>     spring.datasource.username=root
>     spring.datasource.password=root
>     spring.datasource.url=jdbc:mysql://localhost:3306/mybatis?useUnicode=true&characterEncoding=utf-8&serverTimezone=UTC
>     spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
> 
>  *  测试
> 
>     package com.wei;
>     
>     import org.junit.jupiter.api.Test;
>     import org.springframework.beans.factory.annotation.Autowired;
>     import org.springframework.boot.test.context.SpringBootTest;
>     
>     import javax.sql.DataSource;
>     import javax.xml.crypto.Data;
>     import java.sql.SQLException;
>     
>     @SpringBootTest
>     class Springboot04MybatisApplicationTests {
>          
>     
>         @Autowired(required = false)
>         DataSource dataSource;
>     
>         @Test
>         void contextLoads() throws SQLException {
>          
>             System.out.println("=================");
>             System.out.println(dataSource.getClass());
>             System.out.println(dataSource.getConnection());
>         }
>     }

>  *  依赖导入pom.xml
> 
>     <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>2.3.0</version>
>             </dependency>
>             
>             <dependency>
>                 <groupId>org.projectlombok</groupId>
>                 <artifactId>lombok</artifactId>
>             </dependency>
>         	
>             <dependency>
>                 <groupId>org.springframework.boot</groupId>
>                 <artifactId>spring-boot-starter-jdbc</artifactId>
>             </dependency>
>     		
>             <dependency>
>                 <groupId>com.mysql</groupId>
>                 <artifactId>mysql-connector-j</artifactId>
>                 <scope>runtime</scope>
>             </dependency>
>         	
>             <dependency>
>                 <groupId>org.springframework.boot</groupId>
>                 <artifactId>spring-boot-starter-test</artifactId>
>                 <scope>test</scope>
>             </dependency>
>         </dependencies>
> 
>  *  编写pojo/user
> 
>     package com.wei.pojo;
>     
>     import lombok.AllArgsConstructor;
>     import lombok.Data;
>     import lombok.NoArgsConstructor;
>     
>     @Data
>     @AllArgsConstructor
>     @NoArgsConstructor
>     public class User {
>          
>         private int id;
>         private String name;
>         private String pwd;
>     }
> 
>  *  编写mapper/UserMapper接口类
> 
>     package com.wei.mapper;
>     
>     import com.wei.pojo.User;
>     import org.apache.ibatis.annotations.Mapper;
>     import org.springframework.stereotype.Repository;
>     
>     import java.util.List;
>     
>     @Mapper
>     @Repository
>     public interface UserMapper {
>          
>     
>         List<User> queryUserList();
>     
>         User queryUserById(int id);
>     
>         int addUser(User user);
>     
>         int updateUser(User user);
>     
>         int deleteUser(int id);
>     
>     }
> 
>  *  编写resources/mybatis/mapper/UserMapper.xml接口映射器
> 
>     <?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.wei.mapper.UserMapper">
>     
>         <select id="queryUserList" resultType="User">
>             select *
>             from mybatis.user;
>         </select>
>     
>         <select id="queryUserById" resultType="User">
>             select *
>             from mybatis.user
>             where id = #{id};
>         </select>
>     
>         <insert id="addUser" parameterType="User">
>             insert into mybatis.user (id, name, pwd)
>             values (#{id}, #{name}, #{pwd});
>         </insert>
>     
>         <update id="updateUser" parameterType="User">
>             update mybatis.user
>             set name=#{name},
>                 pwd=#{pwd}
>             where id = #{id};
>         </update>
>     
>         <delete id="deleteUser" parameterType="int">
>             delete
>             from mybatis.user
>             where id = #{id};
>         </delete>
>     
>     </mapper>
> 
>  *  编写Controller/UserController控制层
> 
>     package com.wei.controller;
>     
>     import com.wei.mapper.UserMapper;
>     import com.wei.pojo.User;
>     import org.springframework.beans.factory.annotation.Autowired;
>     import org.springframework.web.bind.annotation.GetMapping;
>     import org.springframework.web.bind.annotation.RestController;
>     
>     import java.util.List;
>     
>     @RestController
>     public class UserController {
>          
>     
>         @Autowired
>         private UserMapper userMapper;
>     
>         //查询全部用户
>         @GetMapping("queryUserList")
>         public List<User> queryUserList() {
>          
>             List<User> userList = userMapper.queryUserList();
>             for (User user : userList) {
>          
>                 System.out.println(user);
>             }
>             return userList;
>         }
>     
>         //添加用户
>         @GetMapping("addUser")
>         public String addUser() {
>          
>             userMapper.addUser(new User(5, "王湾", "456"));
>             return "ok";
>         }
>     
>         //修改用户
>         @GetMapping("updateUser")
>         public String updateUser() {
>          
>             userMapper.updateUser(new User(5, "王湾", "123456"));
>             return "ok";
>         }
>     
>         //删除用户
>         @GetMapping("deleteUser")
>         public String deleteUser() {
>          
>             userMapper.deleteUser(5);
>             return "ok";
>         }
>     }
> 
>  *  编写resources/application.properties：配置数据源、整合mybatis
> 
>     #配置数据源
>     spring.datasource.username=root
>     spring.datasource.password=root
>     spring.datasource.url=jdbc:mysql://localhost:3306/mybatis?useUnicode=true&characterEncoding=utf-8&serverTimezone=UTC
>     spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
>     
>     #整合mybatis
>     mybatis.type-aliases-package=com.wei.pojo
>     mybatis.mapper-locations=classpath:mybatis/mapper/*.xml

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[wei_shuo 1]: https://bbs.csdn.net/forums/wei_shuo_study
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