• SpringBoot详解（二）

    SpringBoot（二）

    一、整合JDBC

    1. 建立springboot项目，添加依赖：web，jdbcAPI ，Mysql driver
    2. 写配置
    spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    password: 123456
    username: root
    url: jdbc:mysql://localhost:3306/employee?useUnicode=true&characterEncoding=utf-8

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    1. 测试是否连接上
    package com.example;

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 Springboot05DataApplicationTests {
    //引入数据源
    @Autowired
    DataSource dataSource;

    @Test
    void contextLoads() throws SQLException {
        //输出看看数据源是什么
        System.out.println(dataSource.getClass());//class com.zaxxer.hikari.HikariDataSource
        //获取连接
        Connection connection = dataSource.getConnection();
        System.out.println(connection);
        // xxxxTemplate:SpringBoot  已经配置好模板bean，拿来即用 CRUD


        //关闭连接
        connection.close();
    }

}


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    1. 不写实体类，用jdbc操作数据库，操作CRUD
    package com.example.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
    JdbcTemplate jdbcTemplate;

    //查询数据库表的所有信息
    //没有实体类，数据库中的东西，怎么获取 Map
    @GetMapping("/userList")
    public List<Map<String,Object>>userList(){
        String sql="select * from employee";
        List<Map<String, Object>> mapList = jdbcTemplate.queryForList(sql);
        return mapList;
    }
    @GetMapping("/departmentList")
    public List<Map<String,Object>>departmentList(){
        String sql="select * from department";
        List<Map<String, Object>> list = jdbcTemplate.queryForList(sql);
        return list;
    }
    //增加
    @GetMapping("/addDepartment")
    public String addDepartment(){
        String sql = "insert into employee.department(id,departmentName)values(6,'勤学部')";
        jdbcTemplate.update(sql);
        return "update-ok";
    }
    //修改
    @GetMapping("/updateDepartment")
    public String updateDepartment(){
        String sql = "update employee.department set 'departmentName'='党委部' where id=4";
       jdbcTemplate.update(sql);
        return "update-ok";

    }
    //删除
    @GetMapping("/delDepartment")
    public String delDepartment(){
        String sql = "delete from employee.department where id=3";
        jdbcTemplate.update(sql);
        return "update-ok";
    }

}


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    二、整合Druid数据源

    1. DRUID简介
    • Druid是阿里巴巴开源台上一个数据库连接池实现，结合了C3P0、DBCP、PROXOOL等DB池的优点，同时加入了日志监控。
    • Druid可以很好的监控DB池连接和SQL的执行情况，天生就是针对监控而生的DB连接池
    • Springboot2.0以上默认使用HiKari 数据源，可以说Hikari 与 Driud都是当前Java web上最优秀的数据源
    1. 使用Druid数据源
    • 导入依赖去maven官网
    
<dependency>
    <groupId>com.alibabagroupId>
    <artifactId>druidartifactId>
    <version>1.2.11version>
dependency>

 <dependency>
            <groupId>log4jgroupId>
            <artifactId>log4jartifactId>
            <version>1.2.17version>
        dependency>


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    • 配置druid
    
    #SpringBoot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: 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
    #如果运行时报错，导入log4j即可（maven）
    filters: stat,wall,log4j
    maxPoolPreparedStatementPerConnectionSize: 20
    useGlobalDataSourceStat: true
    connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500

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    • 自定义druid配置
    @Configuration
public class DruidConfig {
    //将自定义配置和配置文件application.yml绑定
    @ConfigurationProperties(prefix = "spring.datasource")
    @Bean
    public DataSource druidDataSource(){
        return new DruidDataSource();
    }

    //后台监控 web.xml
    //因为springboot内置了servlet容器，所以没有web.xml，替换方法ServletRegistrationBean

    //后台监控功能自定义
    @Bean
    public ServletRegistrationBean a(){
        ServletRegistrationBean<StatViewServlet> bean = new ServletRegistrationBean<>(new StatViewServlet(), "/druid/*");
        //后台需要有人登录账号密码配置
        HashMap<String, String> initParameters = new HashMap<>();
        //增加配置
        initParameters.put("loginUsername","admin");
        initParameters.put("loginPassword","123456"); //登录的key是固定的，不能改
        //允许谁可以访问
        initParameters.put("allow","");  //都能访问
        //禁止谁能访问   initParameters.put("kaungshne","192.168.11.123");

        bean.setInitParameters(initParameters);//设置初始化参数
        return bean;
    }
  //通过访问localhost:8080/druid 可以进入监控后台
  
    //自定义filter过滤器
    public FilterRegistrationBean webStatFilter(){
        FilterRegistrationBean bean = new FilterRegistrationBean();
        bean.setFilter(new WebStatFilter());
        HashMap<String, String> initParameters = new HashMap<>();
        //这些东西不统计~（过滤掉）
        initParameters.put("exclusions","*.js,*.css,/druid/*");



        //过滤哪些请求
        bean.setInitParameters(initParameters);

        return bean;
    }
}


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    配置容器都是通过这样的方法自定义，多看源码，提示需要什么就new什么

    三、整合Mybatis框架

    1. 导入依赖
    
<dependency>
    <groupId>org.mybatis.spring.bootgroupId>
    <artifactId>mybatis-spring-boot-starterartifactId>
    <version>2.2.2version>
dependency>


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    1. 连接数据库，写配置文件（整合mybatis）
    spring:
  datasource:
    username: root
    password: 123456
    url: jdbc:mysql://localhost:3306/employee?useUnicode=true&characterEncoding=utf-8
    driver-class-name: com.mysql.cj.jdbc.Driver

#整合mybatis
mybatis:
  type-aliases-package: com.qian.pojo
  mapper-locations: classpath:mybatis/mapper/*.xml



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    1. 写实体类pojo
    package com.qian.pojo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Department {
    private int id;
    private String departmentName;
}


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    1. DepartmentMapper(增删改查)
    package com.qian.mapper;

import com.qian.pojo.Department;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;

import java.util.List;

//这个注解表示了这是一个mybatis的mapper类：Dao
@Mapper
@Repository
public interface DepartmentMapper {

    List<Department>queryDepartmentList();
    Department queryDepartmentById(int id);
    int addDepartment(Department department);
    int updateDepartment(Department department);
    int deleteDepartment(int id);

}


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    1. DepartmentMapper.xml
    <?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">
<!--namespace=绑定一个对应的Dao/Mapper接口-->
<mapper namespace="com.qian.mapper.DepartmentMapper">
    <select id="queryDepartmentList" resultType="Department">
        select * from department
    </select>

    <select id="queryDepartmentById" parameterType="Department">
        select * from department where id=#{id}
    </select>

    <insert id="addDepartment" parameterType="Department">
        insert into department(id,departmentName)values (#{id},#{departmentName})
    </insert>

    <update id="updateDepartment" parameterType="Department">
        update department set departmentName=#{departmentName} where id = #{id}
    </update>

    <delete id="deleteDepartment" parameterType="int">
        delete from department  where id = #{id}
    </delete>


</mapper>

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    1. 省去了service层，实际开发还是要写service层

    DepartmentController

    package com.qian.controller;

import com.qian.mapper.DepartmentMapper;
import com.qian.pojo.Department;
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 DepartmentController {
    @Autowired
    private DepartmentMapper departmentMapper;
    //查询全部
    @GetMapping("/queryDepartmentList")
    public List<Department>queryDepartmentList(){
        List<Department> departmentList = departmentMapper.queryDepartmentList();
        for (Department department:departmentList){
            System.out.println(department);
        }
        return departmentList;
    }
    //增加一个部门
    @GetMapping("/addDepartment")
    public String addDepartment(){
        departmentMapper.addDepartment(new Department(7,"营销部"));
        return "ok";
    }
    //修改一个部门
    @GetMapping("/updateDepartment")
    public String updateDepartment(){
        departmentMapper.updateDepartment(new Department(1,"人才部"));
        return "ok";
    }
    //删除一个部门
    @GetMapping("/deleteDepartment")
    public String deleteDepartment(){
        departmentMapper.deleteDepartment(6);
        return "ok";
    }
}


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    1. 运行测试
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  • 原文地址：https://blog.csdn.net/m0_56116754/article/details/126174819