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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=UTCdriver-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=UTCdriver-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: 5minIdle: 5maxActive: 20maxWait: 60000timeBetweenEvictionRunsMillis: 60000minEvictableIdleTimeMillis: 300000validationQuery: SELECT 1 FROM DUALtestWhileIdle: truetestOnBorrow: falsetestOnReturn: falsepoolPreparedStatements: 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/log4jfilters: stat,wall,log4jmaxPoolPreparedStatementPerConnectionSize: 20useGlobalDataSourceStat: trueconnectionProperties: 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")@Beanpublic DataSource druidDataSource(){return new DruidDataSource();}//后台监控功能@Beanpublic 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@Beanpublic 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;@Testvoid 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 mapperPUBLIC "-//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.userwhere 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.userset name=#{name},pwd=#{pwd}where id = #{id};</update><delete id="deleteUser" parameterType="int">deletefrom mybatis.userwhere 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 {@Autowiredprivate 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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