data source

data source （ Connection pool ） effect

data source ( Connection pool ) It appears to improve program performance
Instantiate the data source in advance , Initialize some connection resources
Get from the data source when using the connection resource
Return the connected resources to the data source after use

Development steps

1. Import the coordinates of the data source and database driven coordinates
2. Create data source objects
3. Set the basic connection data of the data source
4. Use the data source to obtain connection resources and return connection resources

Sample code （Druid）

Because now druid It's the most popular, so I use druid, The others are similar , But I haven't used it

1. Import the coordinates of the data source and database driven coordinates

Go to maven The central warehouse finds the corresponding coordinates

Warehouse address ：https://mvnrepository.com

Find the corresponding version

I mysql The version is 8.0.16

choice maven Coordinate copy

<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>8.0.16</version>
</dependency>

Entry project pom.xml File import and refresh maven

Druid Is the same

<!-- https://mvnrepository.com/artifact/com.alibaba/druid-spring-boot-starter -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid-spring-boot-starter</artifactId>
    <version>1.2.9</version>
</dependency>

2. Create data source objects

 // Create data source objects 
DruidDataSource source = new DruidDataSource();

3. Set the basic connection data of the data source

        source.setDriverClassName("com.mysql.cj.jdbc.Driver");
        source.setUrl("jdbc:mysql://localhost:3306/syf?useUnicode=true&characterEncoding=UTF-8&useSSL=false&serverTimezone=Asia/Shanghai&zeroDateTimeBehavior=CONVERT_TO_NULL&allowPublicKeyRetrieval=true");
        source.setUsername("root");
        source.setPassword("syf20020816");

4. Use the data source to obtain connection resources and return connection resources

 // 4.  Use the data source to obtain connection resources and return connection resources 
DruidPooledConnection connection = source.getConnection();
System.out.println(connection);
connection.close();

Complete code

package com.exampl.testUtil;

import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.pool.DruidPooledConnection;
import org.junit.jupiter.api.Test;

import java.sql.SQLException;

public class TestDruid {
    

    @Test
    public void DruidTest() throws SQLException {
    
        // Create data source objects 
        DruidDataSource source = new DruidDataSource();
        // 3.  Set the basic connection data of the data source 
        source.setDriverClassName("com.mysql.cj.jdbc.Driver");
        source.setUrl("jdbc:mysql://localhost:3306/syf?useUnicode=true&characterEncoding=UTF-8&useSSL=false&serverTimezone=Asia/Shanghai&zeroDateTimeBehavior=CONVERT_TO_NULL&allowPublicKeyRetrieval=true");
        source.setUsername("root");
        source.setPassword("syf20020816");
  // 4.  Use the data source to obtain connection resources and return connection resources 
        DruidPooledConnection connection = source.getConnection();
        System.out.println(connection);
      
        connection.close();
    }

    
}

Results and explanatory screenshots

Profile extraction （jdbcDruid.properties）

1. stay test.resources Create a new resource package

2. Extract configuration

driverClassName=com.mysql.cj.jdbc.Driver
url:jdbc:mysql://localhost:3306/syf?useUnicode=true&characterEncoding=UTF-8&useSSL=false&serverTimezone=Asia/Shanghai&zeroDateTimeBehavior=CONVERT_TO_NULL&allowPublicKeyRetrieval=true
username:root
password:syf20020816

3. Use the configuration file for database connection

package com.exampl.testUtil;

import com.alibaba.druid.pool.DruidDataSourceFactory;
import com.alibaba.druid.pool.DruidPooledConnection;
import org.junit.jupiter.api.Test;

import javax.sql.DataSource;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.util.Properties;
import java.util.ResourceBundle;

public class TestDruidPro {
    

    @Test
    public void testDruidPro() throws Exception {
    
        // Read configuration file 
        Properties properties = new Properties();
        InputStream resourceAsStream = TestDruidPro.class.getClassLoader().getResourceAsStream("jdbcDruid.properties");
        properties.load(resourceAsStream);
        System.out.println(resourceAsStream);
        // Connect 
        DataSource dataSource = DruidDataSourceFactory.createDataSource(properties);
        Connection connection = dataSource.getConnection();
        System.out.println(connection);

    }
}

Results screenshots

Spring Configure data sources

Use set Methods to inject

1. Import dependence

Here are all my dependencies ,mysql,druid,junit,spring You can just add what you don't have

<dependencies>
        <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.16</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/com.alibaba/druid-spring-boot-starter -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.2.9</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.2.9.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.junit.jupiter</groupId>
            <artifactId>junit-jupiter-api</artifactId>
            <version>${
    junit.version}</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.junit.jupiter</groupId>
            <artifactId>junit-jupiter-engine</artifactId>
            <version>${
    junit.version}</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

2. To write applicationContext.xml

Be careful

stay xml in & Character to use & To replace

<property name="url" value="jdbc:mysql://localhost:3306/syf?useUnicode=true&amp;characterEncoding=UTF-8&amp;useSSL=false&amp;serverTimezone=Asia/Shanghai&amp;zeroDateTimeBehavior=CONVERT_TO_NULL&amp;allowPublicKeyRetrieval=true"></property>

Full configuration

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="driverClassName" value="com.mysql.cj.jdbc.Driver"></property>
        <property name="username" value="root"></property>
        <property name="password" value="syf20020816"></property>
        <property name="url" value="jdbc:mysql://localhost:3306/syf?useUnicode=true&amp;characterEncoding=UTF-8&amp;useSSL=false&amp;serverTimezone=Asia/Shanghai&amp;zeroDateTimeBehavior=CONVERT_TO_NULL&amp;allowPublicKeyRetrieval=true"></property>
    </bean>
</beans>

3. test

package com.exampl.testUtil;

import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.pool.DruidPooledConnection;
import org.junit.jupiter.api.Test;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;

public class TestDruid {
    

    @Test
    public void springDruid() throws SQLException {
    
        // load spring The configuration file 
        ClassPathXmlApplicationContext app = new ClassPathXmlApplicationContext("applicationContext.xml");
        DataSource dataSource = (DataSource) app.getBean("dataSource");
        Connection connection = dataSource.getConnection();
        System.out.println(connection);
        connection.close();
    }


}

result

Optimize Spring Configure data sources

Our optimization plan is to jdbc Configuration files and spring Separation of configuration files , Form two separate domains , Then call the domain

1. Introduce namespace and address

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

2. Load external properties

<context:property-placeholder location="classpath:jdbcDruid.properties"></context:property-placeholder>

3. rewrite < property >

<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="driverClassName" value="${driverClassName}"></property>
        <property name="username" value="${username}"></property>
        <property name="password" value="${password}"></property>
        <property name="url"
                  value="${url}"></property>
    </bean>

complete applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
    <context:property-placeholder location="classpath:jdbcDruid.properties"></context:property-placeholder>
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="driverClassName" value="${driverClassName}"></property>
        <property name="username" value="${username}"></property>
        <property name="password" value="${password}"></property>
        <property name="url"
                  value="${url}"></property>
    </bean>
</beans>