[Java知识库]SpringBoot之----如何整合Druid数据源

1、老规矩，先引入依赖：
pom.xml

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.6</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>

2、配置文件中加入Druid配置：
application.yml

spring:
  datasource:
    username: root
    password: admin
    #?serverTimezone=UTC解决时区的报错
    url: jdbc:mysql://localhost:3306/mybatis?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
    driver-class-name: com.mysql.cj.jdbc.Driver
    type: com.alibaba.druid.pool.DruidDataSource片

3、测试一下，看数据源是否变化：
Springboot04DataApplicationTests.java

package com.wlm;

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 Springboot04DataApplicationTests {
    @Autowired
    DataSource dataSource;
    @Test
    void contextLoads() throws SQLException {
        //查看默认的数据源: com.zaxxer.hikari.HikariDataSource
        System.out.println(dataSource.getClass());
        //获得数据库连接
        Connection connection = dataSource.getConnection();
        System.out.println(connection);
        //我们以后会经常看见xxxxTemplate，这个是spring boot已经配置好的模板@bean，拿来即用
        //关闭
        connection.close();
    }

}

4、运行之后，我们发现数据源确实发生了变化：


5、那运行配置一个试一下：
项目目录结构：

代码部分：
pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.6.0</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.wlm</groupId>
    <artifactId>springboot-04-data</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>springboot-04-data</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.6</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

application.yml

spring:
  datasource:
    username: root
    password: admin
    #?serverTimezone=UTC解决时区的报错
    url: jdbc:mysql://localhost:3306/mybatis?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
    driver-class-name: com.mysql.cj.jdbc.Driver
    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

JDBCController.java

package com.wlm.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;
    //查询数据库的所有信息
    //如果没有实体类，我们直接用map获取数据库中的东西
    @GetMapping("/userList")
    public List<Map<String,Object>> userList(){
        String sql = "select * from 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 (1,'小马','88378')";
        jdbcTemplate.update(sql);
        return "addUser-ok";
    }
    @GetMapping("/updateUser/{id}")
    public String updateUser(@PathVariable("id") int id){
        String sql = "update mybatis.user set name=?,pwd=? where id="+id;
        //封装
        Object[] objects = new Object[2];
        objects[0] = "小彭";
        objects[1] = "456789";
        jdbcTemplate.update(sql,objects);
        return "updateUser-ok";
    }
    @GetMapping("/deleteUser/{id}")
    public String deleteUser(@PathVariable("id") int id){
        String sql = "delete from mybatis.user where id = ?";
        jdbcTemplate.update(sql,id);
        return "deleteUser-ok";
    }
}

DruidConfig.java

package com.wlm.config;

import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.support.http.StatViewServlet;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.sql.DataSource;
import java.util.HashMap;

@Configuration
public class DruidConfig {
    @ConfigurationProperties(prefix = "spring.datasource")
    @Bean
    public DataSource druidDataSource(){
        return new DruidDataSource();
    }
    //后台监控，相当于web.xml ServletRegistrationBean
    //因为SpringBoot内置了servlet容器，所以没有web.xml，替代办法：ServletRegistrationBean
    @Bean
    public ServletRegistrationBean statViewServlet(){
        ServletRegistrationBean<StatViewServlet> bean =
                new ServletRegistrationBean<>(new StatViewServlet(), "/druid/*");

        //后台需要有人登陆，账号密码配置
        HashMap<String, String> initParameters = new HashMap<>();
        //增加配置
        initParameters.put("loginUsername","admin");//登陆的key是固定的，loginUsername和loginPassword
        initParameters.put("loginPassword","123456");
        //允许谁可以访问
        initParameters.put("allow","");
        //禁止谁能访问，例如：initParameters.put("chen","111.111.11.1");
        bean.setInitParameters(initParameters);//设置初始化参数
        return bean;
    }
}

运行结果：

输入我们预先设置好的账号密码既可以登陆进去(账号为：admin和密码为：123456);

那我们执行一个SQL试一下：

然后再去查看：

我们想加一个功能也是同样道理的，例如加一个过滤功能：

    //filter
    @Bean
    public FilterRegistrationBean webStatFilter(){
        FilterRegistrationBean<Filter> bean = new FilterRegistrationBean<>();
        bean.setFilter(new WebStatFilter());
        //可以过滤哪些请求
        Map<String,String> initParameters = new HashMap<>();
        //这些东西不进行统计
        initParameters.put("exclusions","*.js,*.css,/druid/*");
        bean.setInitParameters(initParameters);
        return bean;
    }