<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.wangyulong</groupId>
    <artifactId>maven-demo</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>
    <dependencies>
        <dependency>       <--导入mysql-connector-java包-->
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.49</version>
        </dependency>
    </dependencies>
</project>

在pom.xml里导入mysql-connector-java包

第一种连接方式setUrl连接。

import com.mysql.jdbc.Connection;
import com.mysql.jdbc.PreparedStatement;
import com.mysql.jdbc.jdbc2.optional.MysqlDataSource;

import java.sql.ResultSet;
import java.sql.SQLException;

public class myJDBC {
    public static void main(String[] args) throws SQLException {
        MysqlDataSource mysqlDataSource=new MysqlDataSource();
        mysqlDataSource.setUrl("jdbc:mysql://127.0.0.1:3306/db_11_20?characterEncoding=utf8&useSSL=false&serverTimezone=Asia/Shanghai");
        mysqlDataSource.setUser("root");
        mysqlDataSource.setPassword("123456");
        Connection connnection = null;
        try{
            connnection=  mysqlDataSource.getConnection();
            String sql="select * from exam_result";
            PreparedStatement preparedStatement=null;
            try{
                preparedStatement= connnection.prepareStatement(sql);
                ResultSet resultSet=null;
                try{
                    resultSet=preparedStatement.executeQuery();
                    while (resultSet.next()){
                        int id=resultSet.getInt("id");
                        String name=resultSet.getString("name");
                        double chinese=resultSet.getDouble("chinese");
                        double math=resultSet.getDouble("math");
                        double english=resultSet.getDouble("english");
                        System.out.printf("%d %s %.1f %.1f %.1f\n",id,name,chinese,math,english);

                    }
                }finally {
                    if(resultSet!=null){
                        resultSet.close();
                    }
                }
            }finally {
                if(preparedStatement!=null){
                    preparedStatement.close();
                }
            }
        } catch (SQLException throwables) {
            throwables.printStackTrace();

        }finally {
            if(connnection!=null){
                connnection.close();
            }
        }

    }
}

第二种连接方式set方法

import com.mysql.jdbc.Connection;
import com.mysql.jdbc.PreparedStatement;
import com.mysql.jdbc.jdbc2.optional.MysqlDataSource;

import java.sql.ResultSet;
import java.sql.SQLException;

public class myJDBC {
    public static void main(String[] args) throws SQLException {
        MysqlDataSource mysqlDataSource=new MysqlDataSource();
        mysqlDataSource.setServerName("127.0.0.1");
        mysqlDataSource.setPort(3306);
        mysqlDataSource.setCharacterEncoding("utf8");
        mysqlDataSource.setDatabaseName("db_11_20");
        mysqlDataSource.setServerTimezone("Asia/Shanghai");
        //mysqlDataSource.setUrl("jdbc:mysql://127.0.0.1/db_11_20?characterEncoding=utf8&useSSL=false&serverTimezone=Asia/Shanghai");
        mysqlDataSource.setUser("root");
        mysqlDataSource.setPassword("123456");
        mysqlDataSource.setUseSSL(false);
        Connection connnection = null;
        try{
            connnection= mysqlDataSource.getConnection();
            String sql="select * from exam_result";
            PreparedStatement preparedStatement=null;
            try{
                preparedStatement=  connnection.prepareStatement(sql);
                ResultSet resultSet=null;
                try{
                    resultSet=preparedStatement.executeQuery();
                    while (resultSet.next()){
                        int id=resultSet.getInt("id");
                        String name=resultSet.getString("name");
                        double chinese=resultSet.getDouble("chinese");
                        double math=resultSet.getDouble("math");
                        double english=resultSet.getDouble("english");
                        System.out.printf("%d %s %.1f %.1f %.1f\n",id,name,chinese,math,english);

                    }
                }finally {
                    if(resultSet!=null){
                        resultSet.close();
                    }
                }
            }finally {
                if(preparedStatement!=null){
                    preparedStatement.close();
                }
            }
        } catch (SQLException throwables) {
            throwables.printStackTrace();

        }finally {
            if(connnection!=null){
                connnection.close();
            }
        }

    }
}