使用JDBC实现简单的宠物系统（增删改查）

BaseDao类（jdbc实现数据库连接，增删改查功能）
package dao2;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Scanner;

import entity.pet;

public class BaseDao {

private static Connection getConn() {
    String driver = "com.mysql.jdbc.Driver";
    String url = "jdbc:mysql://localhost:3306/test";
    String username = "root";
    String password = "123123";
    Connection conn = null;
    try {
        Class.forName(driver); //classLoader,加载对应驱动
        conn = (Connection) DriverManager.getConnection(url, username, password);
        System.err.println("连接成功");
    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    } catch (SQLException e) {
        e.printStackTrace();
    }
    return conn;
}
/*增加*/
public static int insert(pet p) {
    Connection conn = getConn();
    int i = 0;
    String sql = "INSERT INTO pet(petName,petBread,petSex,birthday,description) VALUES(?,?,?,?,?)";
    PreparedStatement pstmt;
    try {
        pstmt = (PreparedStatement) conn.prepareStatement(sql);
        pstmt.setString(1, p.getPetName());
        pstmt.setString(2, p.getPetBread());
        pstmt.setString(3, p.getPetSex());
        pstmt.setString(4, p.getBirthday());
        pstmt.setString(5, p.getDescription());
        i = pstmt.executeUpdate();
        pstmt.close();
        conn.close();
    } catch (SQLException e) {
        e.printStackTrace();
    }
    return i;
}
/*改*/
public static int update() {
	Scanner s=new Scanner(System.in);
	System.err.println("请输入您要修改的宠物的名字:");
	pet p=new pet();
	String n1 = s.next();
	
    Connection conn = getConn();
    int i = 0;
    String sql = "update pet set petName='" + p.getPetName() + "' where Name='" + p.getPetName() + "'";
    PreparedStatement pstmt;
    try {
        pstmt = (PreparedStatement) conn.prepareStatement(sql);
        i = pstmt.executeUpdate();
        System.out.println("resutl: " + i);
        pstmt.close();
        conn.close();
    } catch (SQLException e) {
        e.printStackTrace();
    }
    return i;
}
/*查*/
public static Integer getAll() {
    Connection conn = getConn();
    String sql = "select * from pet";
    PreparedStatement pstmt;
    try {
        pstmt = (PreparedStatement)conn.prepareStatement(sql);
        ResultSet rs = pstmt.executeQuery();
        int col = rs.getMetaData().getColumnCount();
        System.out.println("============================");
        while (rs.next()) {
            for (int i = 1; i <= col; i++) {
                System.out.print(rs.getString(i) + "\t");
                if ((i == 2) && (rs.getString(i).length() < 8)) {
                    System.out.print("\t");
                }
             }
            System.out.println("");
        }
            System.out.println("============================");
    } catch (SQLException e) {
        e.printStackTrace();
    }
    return null;
}


/*删*/
public static int delete(String petName) {
    Connection conn = getConn();
    int i = 0;
    String sql = "delete from pet where petName='" + petName + "'";
    PreparedStatement pstmt;
    try {
        pstmt = (PreparedStatement) conn.prepareStatement(sql);
        i = pstmt.executeUpdate();
        System.out.println("resutl: " + i);
        pstmt.close();
        conn.close();
    } catch (SQLException e) {
        e.printStackTrace();
    }
    return i;
}

}

entity类
package entity;

import java.sql.Date;

public class pet {
private int petId;
private String petName;
private String petBread;
private String petSex;
private String birthday;
private String description;
public pet(int petId, String petName, String petBread, String petSex,
String birthday, String description) {

	this.petId = petId;
	this.petName = petName;
	this.petBread = petBread;
	this.petSex = petSex;
	this.birthday = birthday;
	this.description = description;
}
public pet() {
	
	
}



public int getPetId() {
	return petId;
}
public void setPetId(int petId) {
	this.petId = petId;
}
public String getPetName() {
	return petName;
}
public void setPetName(String petName) {
	this.petName = petName;
}
public String getPetBread() {
	return petBread;
}
public void setPetBread(String petBread) {
	this.petBread = petBread;
}
public String getPetSex() {
	return petSex;
}
public void setPetSex(String petSex) {
	this.petSex = petSex;
}
public String getBirthday() {
	return birthday;
}
public void setBirthday(String birthday) {
	this.birthday = birthday;
}
public String getDescription() {
	return description;
}
public void setDescription(String description) {
	this.description = description;
}

}