面向对象程序设计(java)题库(7)

}

public DBUtil(){ getConnection(); try {

st = conn.createStatement(); } catch (SQLException e) { e.printStackTrace(); } } /**

* 数据库查询

* @param sql 传入的SQL语句 */

public void executeQuery(String sql){ try{

rs=st.executeQuery(sql);//执行SQL语句获得结果集 }catch(Exception e){

System.out.println(\执行executeQuery(String sql)方法出\+sql); e.printStackTrace();//打印出错误原因 }

} /**

* 数据库增加/删除/修改

* @param sql 传入的SQL语句 * @return >0执行成功 */

public int executeUpdate(String sql){ int ret=-1; try{

ret=st.executeUpdate(sql);//执行SQL语句对数据表进行操作，变量ret存放对表修改了多少行

}catch(Exception e){

System.out.println(\执行executeUpdate(sql)方法出错：\+sql); e.printStackTrace();//打印出错误原因 } finally{ db.close(); }

return ret;

} /**

* 数据库关闭 */

public void close(){ try {

if (rs!=null){

rs.close();//关闭结果集 }

if (st!=null){

st.close();//关闭Statement对象 }

if (conn!=null){

conn.close();//关闭连接 }

}catch(Exception e){

System.out.println(\执行close()方法出错：\); e.printStackTrace(); } } }

package com.zdsoft.po; public class Record {

private String recordId;//专辑编号 private String recordName;//专辑名 private String singerName;//歌手名 private String singerSex;//歌手性别 public String getRecordId() { return recordId; }

public void setRecordId(String recordId) { this.recordId = recordId; }

public String getRecordName() { return recordName; }

public void setRecordName(String recordName) { this.recordName = recordName; }

public String getSingerName() { return singerName; }

public void setSingerName(String singerName) { this.singerName = singerName; }

public String getSingerSex() { return singerSex; }

public void setSingerSex(String singerSex) { this.singerSex = singerSex; }

}

package com.zdsoft.dao; import java.sql.ResultSet;

import java.sql.SQLException; import java.util.ArrayList; import java.util.List; import com.DBUtil;

import com.zdsoft.po.Student; public class RecordDao { DBUtil db = null; public RecordDao() { db = new DBUtil(); } /** * 通过歌手名查找叫他的多个专辑 * @param singer_name 歌手名 * @return 专辑信息列表 */ public List< Record > findRecords(String singer_name) { List< Record > list = new ArrayList< Record >(); String sql = \ + singer_name + \ db.executeQuery(sql); ResultSet res = db.getRs(); try { while (res.next()) { Record r = new Record(); r.setRecordId(res.getString(\ r.setRecordName(res.getString(\ r.setSingerName(res.getString(\ r.setSingerSex(res.getString(\ list.add(r); } } catch (SQLException e) {

e.printStackTrace();

} public void updateRecord (Record record) { String sql = \ + \ + \ + \ if (db.executeUpdate(sql) > 0) { System.out.println(\数据修改成功\ } else { System.out.println(\数据修改失败\ } } }

package com.zdsoft.access; import java.util.List;

import com.zdsoft.dao.RecordDao; import com.zdsoft.po.Record;

public class Access { public static void main(String[] args) { RecordDao dao = new RecordDao (); List records = dao. findRecords (\张学友\ for(Record s:records){//显示张学友的专辑 System.out.print(s.getRecordId()); System.out.print(s.getRecordName()); System.out.print(s.getSingerName()); System.out.println(s.getSingerSex()); } /***************将id为1211专辑的信息进行修改***************/ Record record = new Record(); record.setRecordId(\ record.setRcordName(\大海\ record.setSingerName(\张宇\ record.setSingerSex(\男\ dao.updateRecord(record); } }

}finally{ db.close(); }

return list;