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创建项目

选择MySQL+JDBC+Web

链接数据库

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spring:
datasource:
username: root
password: 123456
url: jdbc:mysql://localhost:3306/jdbc
driver-class-name: com.mysql.jdbc.Driver
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package com.wsx.study.springboot.demo;

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 java.sql.Connection;
import java.sql.SQLException;

@SpringBootTest
class DemoApplicationTests {

@Autowired
DataSource dataSource;

@Test
void contextLoads() throws SQLException {
System.out.println(dataSource.getClass());
Connection connection = dataSource.getConnection();
System.out.println(connection);
connection.close();
}
}

数据源自动配置原理

DataSourceConfiguration,根据配置创建数据源,默认使用Tomcat连接池
SpringBoot支持很多数据源类型,甚至可以自定义,利用反射绑定数据源,并绑定相关属性

配置druid

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<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid-spring-boot-starter</artifactId>
<version>1.1.22</version>
</dependency>

然后再application.yml中配置这个, 就可以用localhost:8080/druid/来访问来

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spring:
# 配置数据库信息
datasource:
druid:
# 数据源配置
username: root
password: 123456
url: jdbc:mysql://127.0.0.1:3306/debug?serverTimezone=GMT%2B8&characterEncoding=UTF-8&useSSL=false # 设置时区
driver-class-name: com.mysql.cj.jdbc.Driver
# 初始化 最小 最大
initial-size: 5
min-idle: 5
max-active: 20
# 配置获取连接等待超时的时间
max-wait: 60000
# 配置间隔多久才进行一次检测,检测需要关闭的空闲连接,单位是毫秒
time-between-eviction-runs-millis: 60000
# 配置一个连接在池中最小生存的时间,单位是毫秒
min-evictable-idle-time-millis: 300000
validation-query: SELECT 'x'
test-while-idle: true
test-on-borrow: false
test-on-return: false
# 打开PSCache,并且指定每个连接上PSCache的大小
poolPreparedStatements: true
maxPoolPreparedStatementPerConnectionSize: 20
# 配置多个英文逗号分隔
filters: stat,wall
# WebStatFilter配置,说明请参考Druid Wiki,配置_配置WebStatFilter
# 是否启用StatFilter默认值true
web-stat-filter:
enabled: true
url-pattern: /*
exclusions: "*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/*"
session-stat-enable: false
session-stat-max-count: 1000
principal-cookie-name: admin
principal-session-name: admin
profile-enable: true
# 根据配置中的url-pattern来访问内置监控页面,如果是上面的配置,内置监控页面的首页是/druid/index.html
# http://loacalhsot:8081/druid
stat-view-servlet:
enabled: true
url-pattern: /druid/* # 监控页面访问路径
# 允许清空统计数据
reset-enable: true
login-username: admin
login-password: 123456
# StatViewSerlvet展示出来的监控信息比较敏感,是系统运行的内部情况,如果你需要做访问控制,可以配置allow和deny这两个参数
# deny优先于allow,如果在deny列表中,就算在allow列表中,也会被拒绝。如果allow没有配置或者为空,则允许所有访问
# 配置的格式
# <IP>
# 或者<IP>/<SUB_NET_MASK_size>其中128.242.127.1/24
# 24表示,前面24位是子网掩码,比对的时候,前面24位相同就匹配,不支持IPV6。
allow:
deny:

整合MyBatis

建表+逆向工程
SpringBoot就自动帮我们把Mapper放到IOC中了

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package com.wsx.demo.dao;


import com.wsx.demo.pojo.Table1;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;

import java.util.List;

@Mapper
public interface Table1Mapper {
@Select("select * from table1")
public List<Table1> selectAll();
}

当然这里也支持批量导入

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@SpringBootApplication
@MapperScan("com.wsx.demo.dao")
public class DemoApplication {

public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}

}

整合JPA

最后是最强的。。。
新建项目的时候选择JPA
JPA你甚至不用自己写sql?好强大

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spring:
datasource:
url: jdbc:mysql://localhost/debug
username: root
password: 123456
driver-class-name: com.mysql.cj.jdbc.Driver
jpa:
hibernate:
ddl-auto: update
show-sql: true
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package com.wsx.demo.entity;

import lombok.Data;

import javax.persistence.*;

@Data
@Entity
@Table(name = "user")
public class User {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
Integer id;
String lastName;
String email;
}
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package com.wsx.demo.repository;

import com.wsx.demo.entity.User;
import org.springframework.data.jpa.repository.JpaRepository;

public interface UserRepository extends JpaRepository<User, Integer> {
}
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package com.wsx.demo.controller;

import com.wsx.demo.entity.User;
import com.wsx.demo.repository.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.ResponseBody;

import java.util.Optional;

@Controller
public class UserController {
@Autowired
UserRepository userRepository;

@GetMapping("/user/select/{id}")
@ResponseBody
public Optional<User> selectUser(@PathVariable("id") Integer id) {
return userRepository.findById(id);
}

@GetMapping("/user/insert")
@ResponseBody
public User insertUser(User user) {
return userRepository.save(user);
}
}

SpringBoot整合Druid