jsp中如何调用javabean
这是我连接数据库的javabean,怎么在jsp页面中调用？
package com;
import java.sql.*;
import java.lang.*;
public class cn
{
public void myconn(){
try{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
String url="jdbc:odbc:Driver={microsoft access driver (*.mdb)};DBQ=c:\\xfv\\db1.mdb";
Connection conn=DriverManager.getConnection(url,"","");
}catch(Exception e){
e.printStackTrace();
}
}
};
jsp:
<%@ page contentType="text/html;charset=gb2312"%>
<%@ page import="java.sql.*"%>
<jsp:useBean id="coon" class="com.cn"/>
<%
Connection con=coon.myconn();
Statement stmt=con.createStatement();
String sql="select * from user";
ResultSet rs=stmt.executeQuery(sql);
while(rs.next()){
out.println(rs.getString(1));
}
%>
错误提示：
org.apache.jasper.JasperException: Unable to compile class for JSP
An error occurred at line: -1 in the jsp file: null
Generated servlet error:
[javac] Since fork is true, ignoring compiler setting.
[javac] Compiling 1 source file
[javac] Since fork is true, ignoring compiler setting.
[javac] C:\tomcat\work\Standalone\localhost\tld\index_jsp.java:60: incompatible types
[javac] found : void
[javac] required: java.sql.Connection
[javac] Connection con=coon.myconn();
[javac] ^
[javac] 1 error
问题点数：0、回复次数：3Top
1 楼lynx1111（任我行:一个PLMM看着就兴奋的男人）回复于 2003-09-04 20:58:05 得分 0
package firm;
import java.sql.*;
public class firm {
String sDBDriver = "sun.jdbc.odbc.JdbcOdbcDriver";
String sConnStr = "jdbc:odbc:firm";
private Connection conn = null;
private Statement stmt = null;
ResultSet rs = null;
public firm() {
try {
Class.forName(sDBDriver);
}
catch(java.lang.ClassNotFoundException e) {
System.err.println("firm(): " + e.getMessage());
}
}
public ResultSet executeQuery(String sql) {
rs = null;
try {
conn = DriverManager.getConnection(sConnStr);
stmt = conn.createStatement();
rs = stmt.executeQuery(sql);
}
catch(SQLException ex) {
System.err.println("aq.executeQuery: " + ex.getMessage());
}
return rs;
}
public void executeUpdate(String sql) {
stmt = null;
rs=null;
try {
conn = DriverManager.getConnection(sConnStr);
stmt = conn.createStatement();
stmt.executeQuery(sql);
stmt.close();
conn.close();
}
catch(SQLException ex) {
System.err.println("aq.executeQuery: " + ex.getMessage());
}
}
public void closeStmt(){
try{
stmt.close();
}
catch(SQLException e){
e.printStackTrace();
}
}
public void closeConn(){
try{
conn.close();
}
catch(SQLException e){
e.printStackTrace();
}
}
}
Top
2 楼xfv（xf）回复于 2003-09-05 09:32:38 得分 0
楼上那个bean我修改后，编译通过，在jsp中调用，可是没有得出正确的结果。
<%@ page contentType="text/html;charset=gb2312"%>
<%@ page import="java.sql.*"%>
<jsp:useBean id="coon" class="com.cn"/>
<%
try{
String sql="select * form user";
ResultSet rs=coon.executeQuery(sql);
while(rs.next()){
out.println(rs.getString(1)+"<br/>");
}
}catch(Exception e){
e.printStackTrace();
}
%>Top
3 楼zuiren（买醉的人）回复于 2003-09-05 12:25:32 得分 0
首先我有个问题想请教一下，这是符合标准规范的javaBean吗？我怎么看也不象。如果想连接
数据库可以用其他的方法啊，写个servlet或者是用一个辅助类。还可以采用过滤器。不能强行加在一个类里面就认为是javaBean啊。Top
