java对数据库的操作

package com.DateSystem;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.LinkedList;
import java.util.List; import javax.swing.JOptionPane; import com.gui.*;
public class Good_data {
//根据商品名查询
public List<Goods> findGoods(String sql){
List<Goods> list=new LinkedList<Goods>();
Statement stat=null;
ResultSet rs=null; //获取和数据库的连接
Connection conn=ConnectionDriver.getConnection();
try {
//生成Statement对象,封装SQL语句,执行查询
stat=conn.createStatement();
rs=stat.executeQuery(sql);
//处理结果集中数据,读取每一条记录
while(rs.next()){
//int id=rs.getInt(1);
String id=rs.getString(1); String name=rs.getString(2);
String address=rs.getString(3); double in_price=rs.getDouble(4);
double out_price=rs.getDouble(5); int jinhuo=rs.getInt(6);
int chuhuo=rs.getInt(7);
int kucun=rs.getInt(8); Goods d=new Goods(); d.setName(name);
d.setId(id);
d.setAddress(address);
d.setIn_price(in_price);
d.setOut_price(out_price);
d.setKucun(kucun);
d.setJinhuo(jinhuo);
d.setChuhuo(chuhuo);
list.add(d); }
} catch (SQLException e) {
e.printStackTrace();
}finally{
JDBcloss.close(rs, stat, conn);
} return list;
}
//依靠商品号查询
public Goods findStudentById(String id){ System.out.print("goods");
//创建Data对象
Goods data=new Goods();
Statement stat=null;
ResultSet rs=null;
Connection conn=ConnectionDriver.getConnection(); String sql="select * from result where id='"+id+"'";
try {
stat=conn.createStatement();
//执行查询
rs=stat.executeQuery(sql);
//处理结果集
if(rs.next()){
//int id_id=rs.getInt(1);
String id_id=rs.getString(1); String name=rs.getString(2);
String address=rs.getString(3); double in_price=rs.getDouble(4);
double out_price=rs.getDouble(5); int jinhuo=rs.getInt(6);
int chuhuo=rs.getInt(7);
int kucun=rs.getInt(8); data.setId(id_id);
data.setName(name);
data.setAddress(address);
data.setIn_price(in_price);
data.setOut_price(out_price);
data.setKucun(kucun);
data.setJinhuo(jinhuo);
data.setChuhuo(chuhuo); }
} catch (SQLException e) {
e.printStackTrace();
}
return data;
} //对商品信息进行增加、修改、删除
public boolean updateStudent(String sql){
boolean flag=false;
Statement stat=null;
Connection conn=ConnectionDriver.getConnection();
try {
//生成Statement对象,向数据库发送sql指令
stat=conn.createStatement();
int i=stat.executeUpdate(sql);
if(i>0){
flag=true;
}
} catch (SQLException e) {
e.printStackTrace();
}finally{
JDBcloss.close(stat, conn);
} return flag;
}
}
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