SQL---->mySQl数据库1------jdbc简单入门

JDBC（Java Data Base Connectivity,java数据库连接）是一种用于执行SQL语句的Java API，可以为多种关系数据库提供统一访问。

目的:不用学习每个数据库的驱动，学习jdbc接口就好了

下面我就举例一个小demo，连接mysql数据库，查询到表中数据：

首先，我的mysql数据库中数据：

用jdbc，我们要引入mysql-connector-java-5.1.41-bin.jar

jdbcDemo1.java

/**
 * 
 */
package cn.snowing.demo;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import cn.snowing.entity.User;

/**
 * @author: snowing
 * @date : 2017年4月27日
 * jdbc读取数据库信息
 */
public class JdbcDemo1 {

    public static void main(String[] args) throws SQLException, ClassNotFoundException {
        // 这样也行，默认端口
        // String url = "jdbc:mysql:///mydb1";
        String url = "jdbc:mysql://localhost:3306/mydb1";
        String user = "root";
        String password = "1";
        Connection conne = null;    
        Statement st = null;
        ResultSet rs = null;
        try {
            // 1.加载驱动注册了两次驱动
            // DriverManager.registerDriver(new com.mysql.jdbc.Driver());
            // 1.2加载驱动常用方式，只注册了一次驱动
            Class.forName("com.mysql.jdbc.Driver");
            
            
            
            // 2.获取连接
            conne = DriverManager.getConnection(url, user, password);
            st = conne.createStatement();
            
            
            // 4.向数据库发送sql，获取数据库返回的结果集
            rs = st.executeQuery("select * from user;");
            
            
            // 5.从接口集中获取数据
            while (rs.next()) {
                User user1 = new User();
                user1.setId(rs.getInt("id"));
                user1.setUsername(rs.getString("username"));
                user1.setBirthday(rs.getDate("birthday"));
                user1.setEntry_date(rs.getDate("entry_date"));
                user1.setJob(rs.getString("job"));
                user1.setSalary(rs.getFloat("salary"));
                user1.setImage(rs.getString("image"));
                System.out.println(user1.getId());
                System.out.println(user1.getUsername());
                System.out.println(user1.getBirthday());
                System.out.println(user1.getEntry_date());
                System.out.println(user1.getJob());
                System.out.println(user1.getSalary());
                System.out.println(user1.getImage());
            }
        } finally {
            // 6.释放连接,很重要啊，不要忘记！！这里连接一定要释放，所以放入finally中
            if (rs != null) {
                try {
                    rs.close();
                } catch (Exception e) {
                    e.printStackTrace();
                }
                rs = null;
            }
            if (st != null) {
                try {
                    st.close();
                } catch (Exception e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                st = null;
            }
            if (conne != null) {
                try {
                    conne.close();
                } catch (Exception e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                conne = null;
            }
        }

    }
}

 User.java

/**
 * 
 */
package cn.snowing.entity;

import java.util.Date;

/**
 * @author: snowing
 * @date  : 2017年4月28日
 * 
 */
public class User {
	private int id;
	private String username;
	private Date birthday;
	private Date entry_date;
	private String job;
	private float salary;
	private String resume;
	private byte image;
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getUsername() {
		return username;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	public Date getBirthday() {
		return birthday;
	}
	public void setBirthday(Date birthday) {
		this.birthday = birthday;
	}
	public Date getEntry_date() {
		return entry_date;
	}
	public void setEntry_date(Date entry_date) {
		this.entry_date = entry_date;
	}
	public String getJob() {
		return job;
	}
	public void setJob(String job) {
		this.job = job;
	}
	public float getSalary() {
		return salary;
	}
	public void setSalary(float salary) {
		this.salary = salary;
	}
	public String getResume() {
		return resume;
	}
	public void setResume(String resume) {
		this.resume = resume;
	}
	public byte getImage() {
		return image;
	}
	public void setImage(byte b) {
		this.image = b;
	}
	
}

结果：