studentdao.java

jdbc 学习质料

package project.dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import project.common.DbConnection;
import project.common.DbException;
import project.common.DbSql;
import project.vo.StudentVo;

public class StudentDao {
  
  /**
   * 查找数据库中是否存在某一编号的学生
   * @param studentId
   * @return
   */
  public boolean findStudentById(int studentId){
    Connection con = null;
    PreparedStatement stmt = null;
    boolean flag = false;
    ResultSet set = null;
    try{
      con = new DbConnection().getConnection();
      stmt = con.prepareStatement(DbSql.SELECT_STUDENT_BY_ID);
      stmt.setInt(1,studentId);
      set = stmt.executeQuery();
      if(set.next()){
        flag = true;
      }
    }catch(SQLException e){
      System.out.println(e.getMessage());
    }
    return flag;
  }
  
  /**
   * 将一条学生信息插入到数据库中
   * @param value
   * @return
   */
  public boolean InsertStudent(StudentVo value) throws DbException{
    boolean flag = false;
    Connection con = null;
    PreparedStatement stmt = null;
    try{
      if(findStudentById(value.getStudent_id())){
        throw new DbException("数据库中存在相同条件的记录"); 
      }
      con = new DbConnection().getConnection();
      stmt = con.prepareStatement(DbSql.INSERT_STUDENT);
      stmt.setInt(1,value.getStudent_id());
      stmt.setString(2,value.getStudent_name());
      stmt.setString(3,value.getStudent_sex());
      stmt.setString(4,value.getStudent_major());
      stmt.setInt(5,value.getStudent_grade());
      stmt.setString(6,value.getStudent_mail());
      //stmt.setString(7,value.getStudent_address());
      stmt.setString(7,value.getStudent_mobile());
      int count = stmt.executeUpdate();
      if(count != 0){
        flag = true;
      }
    }catch(SQLException e){
      System.out.println(e.getMessage());
    }
    return flag;
  }

}