图5.7 示例5-5运行结果 2 5.4.3 request和response对象在项目案例中的应用 (1)添加留言信息。
要求:从页面添加留言信息,把留言信息保存到数据库中,如果保存没有成功,返回显示留言的首页;反之,提示保存失败信息.
步骤1:将原先编写的代码复制过来使用,如showMessage.jsp和DBManager.java。
步骤2:修改Message.java,添加无参构造函数。修改后的代码如实例5-6所示。示例5-6
package jsp.ms.ch05;
imaport java.util.Date;
public class Message{
private int messageID;
private String title;
private string content;
private string writer;
private Date writeDate;
private int count;
public Message(){
super();
}
/使用构造方法进行初始化
public Message(int messageID,String title,Sting content,String writer,DatewriteDate,int count){
this.messageID = messageID;
this.title = title;
this.contet = content;
this.writer = writer;
this.writeDate = writeDate;
this.count = count;
}
public int getMessageID(){
return messageID;
}
public void setMessageID(intmessageID){
this.messageID = messageID;
}
public String getTitle(){
return title;
}
public void setTitle(String title){
this.title = title;
}
public String getContent(){
this.content = content;
}
public String getWriter(){
return writer;
}
public void setWriter(String writer){
ghis.writer = writer;
}
public Date getWriteDate(){
return writeDate;
}
public void setWriteDate(Date writeDate){
heis.writeDate = writeDate;
}
public intgetCount(){
return count;
}
public void setCount(int count){
this.cout = count;
}
} 步骤3:修改MessageDbOperation.java,添加insertMessage()方法和getMessId()方法.其中,insertMessage()方法负责向数据库中添加一条留言,getMessId()方法获取数据库中留言ID(messageId)的最大值，并将其加1,作为新留言的messageId.代码如示例5-7所示。 示例5-7 packege jsp.ms.ch05;
import java.sql.*;
import java.util.*;
import java.util.Date;
import java.text SimpleDateFormat;
public class MessageDbOperation{
public List getMessageList(){
List mlist = new ArrayList;
Connection con = null;
PreparedStatement pSta = bull;