studentdaoimpl.java

出试卷系统（包括前台教师出卷系统

package daoImpl;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;

import util.JdbcUtil;
import dao.StudentDAO;
import entity.Sanswer;
import entity.Student;

public class StudentDAOImpl implements StudentDAO {

	public Student selectStudentByStudent(String loginName, String loginPassword) {

		Connection con = null;
		PreparedStatement ps = null;
		ResultSet rs = null;
		Student student = null;
		String sql = "select * from t_student s where s.name=? and s.password=?";
		try {
			con = JdbcUtil.getConnection();
			ps = con.prepareStatement(sql);
			ps.setString(1, loginName);
			ps.setString(2, loginPassword);
			rs = ps.executeQuery();
			if(rs.next()) {
				student=new Student();
				student.setId(rs.getLong(1));
				student.setName(rs.getString(2));
				student.setPassword(rs.getString(3));
			}
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			JdbcUtil.release(rs, ps, con);
		}
		return student;
	}

	public void insertSanswer(Long studentid, Long questionid, String sanswer) {
		Connection con = null;
		PreparedStatement ps = null;
		ResultSet rs = null;
		String sql = "insert into t_student_question values(?,?,?,?)";
		try {
			con = JdbcUtil.getConnection();
			ps = con.prepareStatement(sql);
			ps.setInt(1, findAll()+1);
			ps.setLong(2, studentid);
			ps.setLong(3, questionid);
			ps.setString(4, sanswer);
			ps.executeUpdate();
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			JdbcUtil.release(rs, ps, con);
		}		
	}
	public int findAll() {
		int n = 0;
		Connection con = null;
		PreparedStatement ps = null;
		ResultSet rs = null;
		try {
			con = JdbcUtil.getConnection();
			String sql = "select max(id) from t_student_question ";
			ps = con.prepareStatement(sql);
			rs = ps.executeQuery();
			while (rs.next()) {
				n = rs.getInt(1);
			}
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			JdbcUtil.release(rs, ps, con);
		}
		return n;
	}


	public Sanswer selectSanswer(Long studentid, Long questionid) {
		Connection con = null;
		PreparedStatement ps = null;
		ResultSet rs = null;
		Sanswer sanswer = new Sanswer();
		String sql = "select * from t_student_question sq where sq.studentid=? and sq.questionid=?";
		try {
			con = JdbcUtil.getConnection();
			ps = con.prepareStatement(sql);
		    ps.setLong(1, studentid);
		    ps.setLong(2, questionid);
			rs = ps.executeQuery();
			if(rs.next()) {
				sanswer.setQuestionid(rs.getInt(3));
				sanswer.setSanswer(rs.getString(4));
			}
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			JdbcUtil.release(rs, ps, con);
		}
		return sanswer;
	}
	
	public static void main(String[] args) {
		StudentDAOImpl sdi = new StudentDAOImpl();
//		Student student = sdi.selectStudentByStudent("chenlin", "chenlin");
//		System.out.println(student);
		Boolean flag=sdi.selectStudentid(1l,6l);
		System.out.println(flag);
//		sdi.insertSanswer(2, 1, "abc");
//		Sanswer sanswer=sdi.selectSanswer(1, 1);
//		System.out.println(sanswer.getSanswer());
//		
		
	}

	public Boolean selectStudentid(Long studentid,Long examid) {
		Connection con = null;
		PreparedStatement ps = null;
		ResultSet rs = null;
		Student student = null;
		String sql = "select * from t_anlysis a where a.studentid=? and a.examid=?";
		try {
			con = JdbcUtil.getConnection();
			ps = con.prepareStatement(sql);
			ps.setLong(1, studentid);
			ps.setLong(2,examid);
			rs = ps.executeQuery();
			if(rs.next()==false) 
		    return false;
			
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			JdbcUtil.release(rs, ps, con);
		}
           return true;
	}


}