清华大学出版社-郭克华版-Java-Web课后习题答案.rar

package dao; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.Statement; import java.util.ArrayList; import vo.Score; public class ScoreDao { private Connection conn = null; public void initConnection() throws Exception { Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); conn = DriverManager.getConnection("jdbc:odbc:DSSchool", "", ""); } // 返回某门课程所有学生的分数 public ArrayList getAllScoresByCourseno(String courseno) throws Exception { ArrayList al = new ArrayList(); initConnection(); String sql = "SELECT STU.STUNO,STU.STUNAME,SCO.TYPE,SCO.SCORE " + "FROM T_STUDENT STU, T_SCORE SCO " + "WHERE STU.STUNO=SCO.STUNO " + "AND SCO.COURSENO=?"; PreparedStatement ps = conn.prepareStatement(sql); ps.setString(1,courseno); ResultSet rs = ps.executeQuery(); while(rs.next()){ Score score = new Score(); score.setStuno(rs.getString("STUNO")); score.setStuname(rs.getString("STUNAME")); score.setType(rs.getString("TYPE")); score.setScorenumber(rs.getString("SCORE")); al.add(score); } closeConnection(); return al; } // 修改某些学生的分数 public void updateScores(String courseno,String[] type,String[] stuno,String[] score ) throws Exception { initConnection(); String sql = "UPDATE T_SCORE SET SCORE=? WHERE STUNO=? AND TYPE=? AND COURSENO=?"; PreparedStatement ps = conn.prepareStatement(sql); for(int i=0;i<stuno.length;i++){ if(!score[i].equals("")){ ps.setDouble(1,Double.parseDouble(score[i])); ps.setString(2,stuno[i]); ps.setString(3,type[i]); ps.setString(4,courseno); ps.executeUpdate(); } } ps.close(); conn.close(); closeConnection(); } public void closeConnection() throws Exception { conn.close(); } }