Question

jsp提交给servlet是页面空白不提示错误

代码如下：
Example7_2_Servlet.java
package myservlet.control;
import mybean.data.Example7_2_Bean;
import java.io.*;
import java.sql.*;

import javax.servlet.*;
import javax.servlet.http.*;
public class Example7_2_Servlet extends HttpServlet {
public void init(ServletConfig config) throws ServletException {
super.init(config);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
Example7_2_Bean resultBean=null;
try{resultBean=(Example7_2_Bean)request.getAttribute("resultBean");
if(resultBean==null){
resultBean=new Example7_2_Bean();
request.setAttribute("resultBean",resultBean);
}
}
catch(Exception exp){
resultBean=new Example7_2_Bean();
request.setAttribute("resultBean",resultBean);
}
try{Class.forName("com.mysql.jdbc.Driver");
}
catch(Exception e){}
String number=request.getParameter("price");
if(number==null||number.length()==0)
return;
String dataBase=request.getParameter("dataBase");
String tableName=request.getParameter("tableName");
String user=request.getParameter("user");
String password=request.getParameter("password");
float p=Float.parseFloat(number);
Connection con;
Statement sql;
ResultSet rs;
try{
String uri="jdbc:mysql://127.0.0.1/"+dataBase;
con=DriverManager.getConnection(uri,user,password);
sql=con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_READ_ONLY);
String condition="SELECT * FROM" +tableName+ "where price >"+p;
rs=sql.executeQuery(condition);
ResultSetMetaData metaData=rs.getMetaData();
int columnCount=metaData.getColumnCount();
String []columnName=new String[columnCount];
for(int i=0;i<columnName.length;i++){
columnName[i]=metaData.getColumnName(i+1);
}
resultBean.setColumnName(columnName);
rs.last();
int rowNumber=rs.getRow();
String [][]tableRecord=resultBean.getTableRecord();
tableRecord=new String[rowNumber][columnCount];
rs.beforeFirst();
int i=0;
while(rs.next()){
for(int k=0;k<columnCount;k++)
tableRecord[i][k]=rs.getString(k+1);
i++;
}
resultBean.setTableRecord(tableRecord);
con.close();
RequestDispatcher dispatcher=
request.getRequestDispatcher("showRecord.jsp");
dispatcher.forward(request, response);
}
catch(SQLException e){
System.out.println(e);
}
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request,response);
}
}

Answer 1

debug 看一下就知道了！

追问

不好意思，赎本人愚钝，能否再详细一点，多谢。

追答

servlet 里面打几个断点，debug看一下，执行到哪挂了，这种情况应该是后台直接挂了，servlet没有执行完。