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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
<!--springboot-mybatis--> <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> <!--springboot-web--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <!--springboot-mybatis--> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>2.3.0</version> </dependency> <!--lombok--> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> </dependency> <!--jdbc--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-jdbc</artifactId> </dependency> <!--mysql--> <dependency> <groupId>com.mysql</groupId> <artifactId>mysql-connector-j</artifactId> <scope>runtime</scope> </dependency> <!--test--> <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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