mysql数据库的连接和操作

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1.前期准备：
数据库准备：
这里写图片描述

Java建包：

bean包一般是写数据库内的实体类
dao包一般是写对数据库的操作
main包一般是编写主方法
util包主要是工具类和数据库连接
附注：还要记得导入mysql.jar文件
2.bean包：
Animals类：

package com.jikexueyuan.bean;public class Animals {    private int id;    private String name;    private int age;    private int anId;    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 int getAge() {        return age;    }    public void setAge(int age) {        this.age = age;    }    public int getAnId() {        return anId;    }    public void setAnId(int anId) {        this.anId = anId;    }}

AnType类：

package com.jikexueyuan.bean;public class AnType {    private int anId;    private String anName;    public int getAnId() {        return anId;    }    public void setAnId(int anId) {        this.anId = anId;    }    public String getAnName() {        return anName;    }    public void setAnName(String anName) {        this.anName = anName;    }}

2.dao包：
AnimalsDAO

package com.jikexueyuan.dao;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.PseudoColumnUsage;import java.sql.ResultSet;import java.util.ArrayList;import com.jikexueyuan.bean.Animals;import com.jikexueyuan.util.BaseConnection;public class AnimalsDAO {    public ArrayList<Animals> getList(){        ArrayList<Animals> ar = new ArrayList<Animals>();        Connection conn = BaseConnection.getConnection();        PreparedStatement ps = null;        ResultSet rs = null;         String sql = "select * from Animals";        try {            //prepareStatement是SQL执行器对象，获取数据库数据            ps = conn.prepareStatement(sql);            //执行查询操作，把所有的查询放在rs结果集中            rs = ps.executeQuery();            while (rs.next()) {                Animals an = new Animals();                an.setId(rs.getInt("id"));                an.setName(rs.getString("name"));                an.setAge(rs.getInt("age"));                an.setAnId(rs.getInt("anid"));                ar.add(an);            }        } catch (Exception e) {            // TODO: handle exception        }        //关闭资源        finally{            BaseConnection.closeRes(conn, ps, rs);        }        return ar;    }}

AnTypeDAO包：

package com.jikexueyuan.dao;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.util.ArrayList;import com.jikexueyuan.bean.AnType;import com.jikexueyuan.bean.Animals;import com.jikexueyuan.util.BaseConnection;public class AnTypeDAO {    public ArrayList<AnType> getList(){        ArrayList<AnType> ar = new ArrayList<AnType>();        Connection conn = BaseConnection.getConnection();        PreparedStatement ps = null;        ResultSet rs = null;         String sql = "select * from antype";        try {            ps = conn.prepareStatement(sql);            rs = ps.executeQuery();            while (rs.next()) {                AnType an = new AnType();                an.setAnId(rs.getInt("anid"));                an.setAnName(rs.getString("anname"));                ar.add(an);            }        } catch (Exception e) {            e.printStackTrace();        }finally{            BaseConnection.closeRes(conn, ps, rs);        }        return ar;    }}

3.main包：

package com.jikexueyuan.main;import java.util.ArrayList;import com.jikexueyuan.bean.AnType;import com.jikexueyuan.bean.Animals;import com.jikexueyuan.dao.AnTypeDAO;import com.jikexueyuan.dao.AnimalsDAO;public class TestMain {    public static void main(String[] args) {        AnimalsDAO ad = new AnimalsDAO();        ArrayList<Animals> ar = ad.getList();        for (Animals an:ar) {            System.out.println(an.getName());        }        AnTypeDAO  atd = new AnTypeDAO();        ArrayList<AnType> arr = atd.getList();        for(AnType an:arr){            System.out.println(an.getAnName());        }    }}

4.util包：
BaseConnection

package com.jikexueyuan.util;import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.ResultSet;public class BaseConnection {    //编写数据库静态连接方法    public static Connection getConnection(){        Connection conn = null;        try {            //加载驱动            Class.forName("com.mysql.jdbc.Driver");            //获取连接            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/animal","root","123321");        } catch (Exception e) {            e.printStackTrace();        }        return conn;    }    //关闭资源的方法    public static void closeRes(Connection conn,PreparedStatement ps,ResultSet rs){        try {            if (ps!=null) {                ps.close();            }            if (rs!=null) {                conn.close();            }            if (conn!=null) {                conn.close();            }        } catch (Exception e) {            e.printStackTrace();        }    }    public static void closeRes(Connection conn,PreparedStatement ps){        try {            if (ps!=null) {                ps.close();            }            if (conn!=null) {                conn.close();            }        } catch (Exception e) {            e.printStackTrace();        }    }}

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