-----连接数据库

package connectdb;

import java.sql.*;

class Dbcon {

// 此处连接数据库，独立开一个类，以后操作数据库的每次连接就不用写这么多

public Connection getCon() {

Connection con = null;

try {

Class.forName("com.mysql.jdbc.Driver");

// 其中test是我们要链接的数据库，user是数据库用户名，password是数据库密码。

// 3306是mysql的端口号，一般是这个

// 后面那串长长的参数是为了防止乱码，免去每次都需要在任何语句都加入一条SET NAMES UTF8

String url = "jdbc:mysql://localhost/testdb?useUnicode=true&characterEncoding=utf8&useSSL=false";

String user = "root";

String password = "basketball";

con = DriverManager.getConnection(url, user, password);

System.out.println("sucess to connect db");

} catch (Exception e) {

System.out.println("fail to connect db");

e.printStackTrace();

}

return con;

}

}

增删改查操作：

package connectdb;

import java.sql.*;

import java.util.ArrayList;

public class applyDb {

//定义一个Student类，存到数据库数据类型是Student

class Student{

private String number;

private String name;

private String grade;

public Student(String num,String name,String grade){

this.number = num;

this.name = name;

this.grade = grade;

}

public String getNumber(){

return number;

}

public String getName(){

return name;

}

public String getGrade(){

return grade;

}

}

//定义一个ArrayList来存放数据

public ArrayList dataList(){

Student stu1 = new Student("1","李青","90");

Student stu2 = new Student("2","小明","60");

ArrayList stu = new ArrayList();

stu.add(stu1);

stu.add(stu2);

return stu;

}

//创建一个表

public void create(){

Connection con = new Dbcon().getCon();

try {

Statement s = con.createStatement();

String creatT = "create table student(number char(10),name char(15),grade char(15))";

s.executeUpdate(creatT);

s.close();

con.close();

System.out.println("sucess to create");

} catch (SQLException e) {

// TODO Auto-generated catch block

System.out.println("fail to create");

e.printStackTrace();

}

}

//插入数据

public void insert(){

Connection con = new Dbcon().getCon();

ArrayList arStu = dataList();

int length = arStu.size();

String number = "";

String name = "";

String grade = "";

PreparedStatement ps = null;

try {

for(int i = 0 ;i

number = arStu.get(i).number;

name = arStu.get(i).name;

grade = arStu.get(i).grade;

String sql = "insert into student values(?,?,?)";

ps = con.prepareStatement(sql);

ps.setString(1,number);

ps.setString(2, name);

ps.setString(3, grade);

ps.executeUpdate();

}

ps.close();

con.close();

System.out.println("sucess to insert");

} catch (SQLException e1) {

// TODO Auto-generated catch block

System.out.println("fail to insert");

e1.printStackTrace();

}

}

//删除数据

public void delete(){

Connection con = new Dbcon().getCon();

String sql = "delete from student where number=?";

PreparedStatement ps = null;

try {

ps = con.prepareStatement(sql);

ps.setString(1, "1");

ps.executeUpdate();

ps.close();

con.close();

System.out.println("sucess to delete");

} catch (SQLException e) {

System.out.println("fail to delete");

// TODO Auto-generated catch block

e.printStackTrace();

}

}

//查找数据

public void query(){

Connection con = new Dbcon().getCon();

String sql = "select * from student where number=?";

PreparedStatement ps = null;

ResultSet rs = null;

try {

ps= con.prepareStatement(sql);

ps.setString(1,"2");

rs = ps.executeQuery();

while(rs.next()){

System.out.println(rs.getString("number"));

System.out.println(rs.getString("name"));

System.out.println(rs.getString("grade"));

}

ps.close();

con.close();

} catch (SQLException e) {

System.out.println("fail to query");

// TODO Auto-generated catch block

e.printStackTrace();

}

}

public static void main(String args[]){

applyDb db = new applyDb();

//db.create();

//db.insert();

//db.delete();

db.query();

}

}