MySQL-DBCP

使用DBCP连接MySQL数据库

1.导入maven坐标

    <dependency>
        <groupId>org.apache.commons</groupId>
        <artifactId>commons-dbcp2</artifactId>
        <version>2.1.1</version>
    </dependency>

2.建立实体类

建立pojo/userinfo实体类，与数据库中userinfo表对应

package pojo;

public class userinfo {
    private Integer id;
    private String college;
    private String name;
    private Integer picId;

    public userinfo(Integer id, String college, String name, Integer picId) {
        this.id = id;
        this.college = college;
        this.name = name;
        this.picId = picId;
    }

    public userinfo() {
    }

    @Override
    public String toString() {
        return "userinfo{" +
                "id=" + id +
                ", college='" + college + '\'' +
                ", name='" + name + '\'' +
                ", picId=" + picId +
                '}';
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getCollege() {
        return college;
    }

    public void setCollege(String college) {
        this.college = college;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getPicId() {
        return picId;
    }

    public void setPicId(Integer picId) {
        this.picId = picId;
    }
}

3.建立数据库配置文件dbcp.properties

在resource文件夹下建立dbcp.properties配置文件

driverClassName = com.mysql.cj.jdbc.Driver
url = jdbc:mysql://127.0.0.1:3306/zzu?serverTimeZone=UTC&characterEncoding=utf-8
username = root
password = XXXXXX
#初试连接数
initialSize=30
#最大活跃数
maxTotal=30
#最大idle数
maxIdle=10
#最小idle数
minIdle=5
#最长等待时间(毫秒)
maxWaitMillis=1000
#程序中的连接不使用后是否被连接池回收(该版本要使用removeAbandonedOnMaintenance和removeAbandonedOnBorrow)
#removeAbandoned=true
removeAbandonedOnMaintenance=true
removeAbandonedOnBorrow=true
#连接在所指定的秒数内未使用才会被删除(秒)(为配合测试程序才配置为1秒)
removeAbandonedTimeout=1

4.建立utils工具类

建立utils/dbcputils工具类

package util;
import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;
import javax.sql.DataSource;
import org.apache.commons.dbcp2.BasicDataSourceFactory;

public class DBCPUtils {
    private static Properties props = new Properties();
    static{
        try{
            props.load(DBCPUtils.class.getClassLoader().
                    getResourceAsStream("dbcp.properties"));
        }catch(Exception e){
            System.out.println("读取配置文件出错");
        }
    }
    public static DataSource getDataSource() {
        try{
            return BasicDataSourceFactory.createDataSource(props);
        }catch(Exception ex){
            System.out.println("获取数据源出错");
            return null;
        }
    }
    public static Connection getConnection() {
        try {
            return getDataSource().getConnection();
        } catch (SQLException e) {
            System.out.println("获取连接失败");
            return null;
        }
    }
    public static void close(Connection conn, ResultSet rs, PreparedStatement prep){
        if(rs != null){
            try{
                rs.close();
                rs = null;
            }catch(Exception e){
                System.out.println("关闭失败");
            }
        }
        if(prep != null){
            try{
                prep.close();
                prep = null;
            }catch(Exception e){
                System.out.println("关闭失败");
            }
        }
        if(conn != null){
            try{
                conn.close();
                conn = null;
            }catch(Exception e){
                System.out.println("关闭失败");
            }
        }
    }
}

5.测试

建立测试类，获取数据库连接，进行数据获取测试

import util.DBCPUtils;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

public class DBCPTest {
    public static void main(String[] args) {
        Connection conn = null;
        try {
            conn = DBCPUtils.getConnection();
            PreparedStatement prepStmt = conn.prepareStatement("select * from userinfo");
            ResultSet rs = prepStmt.executeQuery();
            while (rs.next()) {
                int id = rs.getInt("id");
                String college = rs.getString("college");
                String name = rs.getString("name");
                int picId = rs.getInt("pic_id");
                System.out.println(id + " " + college + " " + name + " " + picId);
            }
        }catch(Exception e){
            System.out.println("出错了");
        }
    }
}

通过以上步骤，可以利用dbcp来进行数据库数据的获取