package jg;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Scanner;
public class DBO {
public static Connection conn = null;
public static Statement stmt = null;
public static PreparedStatement ptmt= null;
public static ResultSet rs = null;
static int result;
@SuppressWarnings("unused")
private Scanner input=new Scanner(System.in);
public static ArrayList<Studengtcourse> getAll() {
ArrayList<Studengtcourse> list=new ArrayList<Studengtcourse>();
conn=DBC.getConn();
try {
stmt=conn.createStatement();
String sql="select * from studengtcourse";
rs=stmt.executeQuery(sql);
while(rs.next())
{
Studengtcourse studengtcourse=new Studengtcourse();
studengtcourse.setId(rs.getInt("id"));
studengtcourse.setStudentName(rs.getString("student_name"));
studengtcourse.setStudentId(rs.getInt("student_id"));
studengtcourse.setEnglishCourse(rs.getInt("english_course"));
studengtcourse.setMathCourse(rs.getInt("math_course"));
studengtcourse.setComputerCourse(rs.getInt("computer_course"));
list.add(studengtcourse);
}
} catch(SQLException e) {
e.printStackTrace();
}finally {
DBC.closeResultSet(rs);
DBC.closeStatement(stmt);
DBC.closeConnection(conn);
}
return list;
}
public static int add(String studengtid, String name, String english, String math, String computer) {
int i=0;
try {
conn=DBC.getConn();
String sql="insert into studengtcourse (student_id,student_name,english_course,math_course,computer_course) values(?,?,?,?,?)";
PreparedStatement ptmt = conn.prepareStatement(sql);
ptmt.setInt(1, Integer.valueOf(studengtid));
ptmt.setString(2, name);
ptmt.setInt(3, Integer.valueOf(english));
ptmt.setInt(4, Integer.valueOf(math));
ptmt.setInt(5, Integer.valueOf(computer));
i=ptmt.executeUpdate();
} catch (SQLException e) {
e.printStackTrace();
System.out.println("连接异常！");
}finally
{
DBC.closePreparedStatement(ptmt);
DBC.closeConnection(conn);
}
return i;
}
public static ArrayList<Studengtcourse> findByName(String name) {
ArrayList<Studengtcourse> list=new ArrayList<Studengtcourse>();
conn=DBC.getConn();
try {
stmt=conn.createStatement();
String sql="select * from studengtcourse where student_name='"+name+"'";
rs=stmt.executeQuery(sql);
while(rs.next())
{
Studengtcourse studengtcourse=new Studengtcourse();
studengtcourse.setId(rs.getInt("id"));
studengtcourse.setStudentName(rs.getString("student_name"));
studengtcourse.setStudentId(rs.getInt("student_id"));
studengtcourse.setEnglishCourse(rs.getInt("english_course"));
studengtcourse.setMathCourse(rs.getInt("math_course"));
studengtcourse.setComputerCourse(rs.getInt("computer_course"));
list.add(studengtcourse);
}
} catch(SQLException e) {
e.printStackTrace();
}finally {
DBC.closeResultSet(rs);
DBC.closeStatement(stmt);
DBC.closeConnection(conn);
}
return list;
}
public static int deleteByName(String name3) {
int i=0;
try {
conn=DBC.getConn();
Statement stmt = conn.createStatement();
String sql="delete from studengtcourse where student_name='"+name3+"'";
i=stmt.executeUpdate(sql);
}catch(SQLException e) {
e.printStackTrace();
System.out.println("连接异常！");
}finally
{
DBC.closePreparedStatement(ptmt);
DBC.closeConnection(conn);
}
return i;
}
public static String updateByName(String xh, String name4, String yy, String sx, String jsj) {
String sql="update studengtcourse set student_id =?,student_name=?,english_course=?,math_course=?,computer_course=? where student_name=?";
try {
int xh1=Integer.valueOf(xh);
int yy1=Integer.valueOf(yy);
int sx1=Integer.valueOf(sx);
int jsj1=Integer.valueOf(jsj);
conn=DBC.getConn();
ptmt=conn.prepareStatement(sql);
ptmt.setInt(1,xh1);
ptmt.setString(2,name4);
ptmt.setInt(3,yy1);
ptmt.setInt(4,sx1);
ptmt.setInt(5,jsj1);
ptmt.setString(6,name4);
result=ptmt.executeUpdate();
if(1==result){
return"修改成功";
}
} catch (SQLException e) {
System.out.println("修改失败");
e.printStackTrace();
}
finally
{
DBC.closeConnection(conn);
}
return "";
}
}
这不就是连接数据库后的select、update和delete操作表记录么，哪个地方不明白？
这个就是jdbc链接收据库的代码，首先得到链接，然后连接得到Statement ，写一个sql，通过Statement 去执行这个sql，得到返回值，遍历返回值，然后给每个对象设置属性，最后添加到list中