日期:2014-05-17  浏览次数:20776 次

简单的更改记录的语句?
JAVABEAN功能:添加一条新记录.并按新记录的style(分类)把stylelist表中相同style(分类)的cou加1.
分不多了.谢谢各位帮帮忙!
Java code

/*
 *网站JAVABEAN
 *添加一条新信息,
 *添加成功显示提示及继续添加的链接.
 *前台页面
 */
package mybean;

import java.sql.*;

public class Publish {
    
    private PreparedStatement pstmt = null;
    private Statement stmt = null;
         private Connection conn = null;
    private String city;
    private String title;
    private String style;
    private String content;
    private String pass;
    private String chec;
    private String addMessage;
    

    
    public Publish(){}
    
    public void setCity(String city){
        this.city=city;
    }
    public void setTitle(String title){
        this.title=title;       
    }
    public void setStyle(String style){
        this.style=style;
    }
    public void setContent(String content){
        //替换HTML字符输出的格式
        content=content.replace("\n","<BR/>");
        content=content.replace(" ","&nbsp;");
        this.content=content;
    }
    public void setPass(String pass){
        this.pass=pass;
    }
    public void setChec(String chec){
        this.chec=chec;
    }
    
    public String getCity(){
        return this.city;
    }
    public String getTitle(){
        return this.title;
    }
    public String getStyle(){
        return this.style;
    }
    public String getContent(){
        return this.content;
    }
    public String getPass(){
        return this.pass;
    }
    public String getChec(){
        return this.chec;
    }
    public String getAddMessage(){
        conn = DBConnSource.getConnection("jdbc/myweb");
            
       try{ 
        String sql="INSERT INTO adver VALUES(?,?,?,?,?,?,?,?)";   
        pstmt = DBConnSource.getPstmt(conn,sql);
        java.util.Date date=new java.util.Date();
        Timestamp tt=new Timestamp(date.getTime());
        pstmt.setInt(1,0);
        pstmt.setString(2,city);
        pstmt.setString(3,style);
        pstmt.setString(4,title);
        pstmt.setString(5,content);
        pstmt.setTimestamp(6,tt);
        pstmt.setString(7,pass);
        pstmt.setString(8,chec);
        
        int flag=pstmt.executeUpdate();
        if(flag>0){
            addMessage="成功添加"+flag+"条记录!";
            String sql2="UPDATE stylelist SET cou=cou+1 WHERE style='"+style+"'";
                       stmt.executeUpdate(sql2); //这一句是Publish.java:89
            }else{
                addMessage="添加记录失败";
            }
      }catch(SQLException e) {
        e.printStackTrace();
    }finally{
        DBConnSource.close(stmt);
        DBConnSource.close(pstmt);
        DBConnSource.close(conn);
    }               
         return addMessage;
    }
}


报错:
exception 

org.apache.jasper.JasperException
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:510)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:393)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)


root cause 

java.lang.NullPointerException
mybean.Publish.getAddMessage(Publish.java:89)
org.apache.jsp.publish2_jsp._jspService(publish2_jsp.java:139)
or