JDBC连接MySQL数据库的标准模板

最新推荐文章于 2022-11-07 16:46:22 发布

原创最新推荐文章于 2022-11-07 16:46:22 发布 · 465 阅读

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#jdbc #mysql #数据库

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本文介绍了一个使用Java JDBC进行数据库操作的示例程序，包括连接数据库、执行SQL查询并获取结果集，以及释放资源的过程。示例展示了如何将查询结果映射到Java对象，并遍历打印所有用户信息。

JdbcDemo.java文件：

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

//释放资源
//JDBC编码的代码模板
public class JdbcDemo5 {

    public static void main(String[] args) {
        List<User> users = new ArrayList<User>();
        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;
        try {
            Class.forName("com.mysql.jdbc.Driver");
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/day15", "root", "");
            stmt = conn.createStatement();
            rs = stmt.executeQuery("select id,name,password,email,birthday from users");

            while(rs.next()){
                User user = new User();
                user.setId(rs.getInt("id"));
                user.setName(rs.getString("name"));
                user.setPassword(rs.getString("password"));
                user.setEmail(rs.getString("email"));
                user.setBirthday(rs.getDate("birthday"));
                users.add(user);
            }

        } catch (Exception e) {
            e.printStackTrace();
        }finally{

            if(rs!=null){
                try {
                    rs.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
                rs = null;
            }
            if(stmt!=null){
                try {
                    stmt.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
                stmt = null;
            }
            if(conn!=null){
                try {
                    conn.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
                conn = null;
            }

        }

        for(User u : users){
            System.out.println("users:"+u);
        }

    }

}

User.java文件：

import java.util.Date;


public class User {

    private int id;
    private String name;
    private String password;
    private String email;
    private Date birthday;
    public User() {
        super();
    }
    public User(int id, String name, String password, String email,
            Date birthday) {
        super();
        this.id = id;
        this.name = name;
        this.password = password;
        this.email = email;
        this.birthday = birthday;
    }
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
    public Date getBirthday() {
        return birthday;
    }
    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    @Override
    public String toString() {
        return "User [id=" + id + ", name=" + name + ", password=" + password
                + ", email=" + email + ", birthday=" + birthday + "]";
    }

}

运行结果：
users:User [id=1, name=zs, password=123456, email=zs@sina.com, birthday=1980-12-04]
users:User [id=2, name=lisi, password=123456, email=lisi@sina.com, birthday=1981-12-04]
users:User [id=3, name=wangwu, password=123456, email=wangwu@sina.com, birthday=1979-12-04]