查询数据的分页
在Mysql数据库中用的是 limit n,m n代表着从第几条显示,m为显示的显示多少行
数据类:成员变量,成员方法(get set)
public class Fruit { private String daihao; private String shuiguoming; private double danjia; private String chandi; private int kucun; private String tupian; public String getDaihao() { return daihao; } public void setDaihao(String daihao) { this.daihao = daihao; } public String getShuiguoming() { return shuiguoming; } public void setShuiguoming(String shuiguoming) { this.shuiguoming = shuiguoming; } public double getDanjia() { return danjia; } public void setDanjia(double danjia) { this.danjia = danjia; } public String getChandi() { return chandi; } public void setChandi(String chandi) { this.chandi = chandi; } public int getKucun() { return kucun; } public void setKucun(int kucun) { this.kucun = kucun; } public String getTupian() { return tupian; } public void setTupian(String tupian) { this.tupian = tupian; } }
访问类:
1.驱动类:
import java.sql.*; public class DBConn { public static String qd="com.mysql.jdbc.Driver"; public static String jdbc="jdbc:mysql://127.0.0.1:3306/mydb"; public static String uid="root"; public static String pwd=""; public static Connection getconnection () throws Exception{ Class.forName(qd); Connection conn=DriverManager.getConnection(jdbc,uid,pwd); return conn; } }
2.访问数据类
import java.sql.*; import java.util.*; import com.maya.shuju.*; public class FruitDao { private Connection conn; private ResultSet re; private PreparedStatement stat; public FruitDao() throws Exception { conn=DBConn.getconnection(); } public ArrayList<Fruit> select(int m, int n ) throws Exception{ ArrayList<Fruit> list = new ArrayList<Fruit>(); String sql="select * from fruit limit ?,?"; stat=conn.prepareStatement(sql); stat.setInt(1, (m-1)*n); //(m-1)*n, m是跳过的行数,-1 再乘n 就是页数对应的行数 stat.setInt(2, n); re=stat.executeQuery(); while (re.next()){ Fruit tada = new Fruit(); tada.setDaihao(re.getString(1)); tada.setShuiguoming(re.getString(2)); tada.setDanjia(re.getDouble(3)); tada.setChandi(re.getString(4)); tada.setKucun(re.getInt(5)); tada.setTupian(re.getString(6)); list.add(tada); } return list; } }
界面类:
import java.util.*; import com.maya.fangwen.*; import com.maya.shuju.*; public class JieMian { public static void main(String[] args) throws Exception { Scanner sc=new Scanner(System.in); System.out.println("请输入页数"); int ys=Integer.parseInt(sc.nextLine()); System.out.println("请输入每页几条"); int ts=Integer.parseInt(sc.nextLine()); ArrayList<Fruit> s=new FruitDao().select(ys, ts); for (int i=0;i<s.size();i++){ System.out.println(s.get(i).getShuiguoming()); } } }
我们不是制造者,我们是代码搬运工