已解决问题
谷歌jggm2587用户在2014.05.09提交了关于“飞剑问道求助！jsp中用j**abean连接**库失败”的提问，欢迎大家涌跃发表自己的观点。目前共有1个回答，最后更新于2024-10-30T13:17:42。我在j**abean中添了代码进行测试，能够连接上**库的，可是到jsp页面调用时，提示“**库连接失败！”代码如下：代码段一：ConnDB.j**a
packageJ**aBeans;
importj**a.sql.Connection;
importj**a.sql.DriverManager;
importj**a.sql.ResultSet;
importj**a.sql.Statement;
publicclassConnDB1{
Connectionconn=**ll;
Statementstmt=**ll;
ResultSetrs=**ll;
publicConnDB1(){
try{Class.forName("com.mysql.jdbc.Driver");
Stringurl="jdbc:mysql://localhost:3306/db_student";
Stringuser="root";
Stringpassword="zhaofan";
conn=DriverManager.getConnection(url,user,password);
stmt=conn.createStatement();
System.out.println("连接MYSQL**库成功！");
}
catch(Exceptione){
System.out.println("连接**库失败！");
System.out.println(e.getMessage());
}
}
publicResultSetquery(Stringsql){
try{
ResultSetrs=stmt.executeQuery(sql);
}
catch(Exceptione){
System.err.println(e.getMessage());
}
returnrs;
}
publicintupdate(Stringsql){
intresult=0;
try{
result=stmt.executeUpdate(sql);
}
catch(Exceptione){
System.err.println(e.getMessage());
}
returnresult;
}
publicvoidclose(){
try{
if(rs!=**ll)rs.close();
}
catch(Exceptione){
e.printStackTrace(System.err);
}
try{
if(stmt!=**ll)stmt.close();
}
catch(Exceptione){
e.printStackTrace(System.err);
}
try{
if(conn!=**ll){
conn.close();
}
}
catch(Exceptione){
e.printStackTrace(System.err);
}
}
}
代码段二：login_u.jsp
<%@pagelanguage="j**a"contentType="text/html;charset=gb2312"
pageEncoding="gb2312"import="j**a.sql.*"%>
<jsp:useBeanid="ConnDB1"scope="page"class="J**aBeans.ConnDB1"/>
<%
Stringusername=request.getParameter("name");
try{
ResultSetrs=ConnDB1.query("select*fromstu_messwherename='"+username+"'");
if(***.next()){
Stringpwd=request.getParameter("password");
if(pwd==rs.getString("password"))
{
session.setAttribute("UserName",username);
response.sendRedirect("index.jsp");
}
}
}
catch(Exceptione)
{System.out.print("您的输入有误！");<br>}
%>希望大家能够帮助她。
详细问题描述及疑问：我在j**abean中添了代码进行测试，能够连接上**库的，可是到jsp页面调用时，提示“**库连接失败！”代码如下：
代码段一：ConnDB.j**a
packageJ**aBeans;
importj**a.sql.Connection;
importj**a.sql.DriverManager;
importj**a.sql.ResultSet;
importj**a.sql.Statement;
publicclassConnDB1{
Connectionconn=**ll;
Statementstmt=**ll;
ResultSetrs=**ll;
publicConnDB1(){
try{Class.forName("com.mysql.jdbc.Driver");
Stringurl="jdbc:mysql://localhost:3306/db_student";
Stringuser="root";
Stringpassword="zhaofan";
conn=DriverManager.getConnection(url,user,password);
stmt=conn.createStatement();
System.out.println("连接MYSQL**库成功！");
}
catch(Exceptione){
System.out.println("连接**库失败！");
System.out.println(e.getMessage());
}
}
publicResultSetquery(Stringsql){
try{
ResultSetrs=stmt.executeQuery(sql);
}
catch(Exceptione){
System.err.println(e.getMessage());
}
returnrs;
}
publicintupdate(Stringsql){
intresult=0;
try{
result=stmt.executeUpdate(sql);
}
catch(Exceptione){
System.err.println(e.getMessage());
}
returnresult;
}
publicvoidclose(){
try{
if(rs!=**ll)rs.close();
}
catch(Exceptione){
e.printStackTrace(System.err);
}
try{
if(stmt!=**ll)stmt.close();
}
catch(Exceptione){
e.printStackTrace(System.err);
}
try{
if(conn!=**ll){
conn.close();
}
}
catch(Exceptione){
e.printStackTrace(System.err);
}
}
}
代码段二：login_u.jsp
<%@pagelanguage="j**a"contentType="text/html;charset=gb2312"
pageEncoding="gb2312"import="j**a.sql.*"%>
<jsp:useBeanid="ConnDB1"scope="page"class="J**aBeans.ConnDB1"/>
<%
Stringusername=request.getParameter("name");
try{
ResultSetrs=ConnDB1.query("select*fromstu_messwherename='"+username+"'");
if(***.next()){
Stringpwd=request.getParameter("password");
if(pwd==rs.getString("password"))
{
session.setAttribute("UserName",username);
response.sendRedirect("index.jsp");
}
}
}
catch(Exceptione)
{System.out.print("您的输入有误！");<br>}
%>期待您的答案，希望你能感受到,我最真诚的谢意
！