如何检查ResultSet是否为空？
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%@page import="java.sql.*"%><%@page import = "java.sql.ResultSet" %>
<%@page import = "java.sql.Connection" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Getting Database Connection</title>
</head>
<body>
<%
ResultSet result = null ;
Connection connection1 = null;
try
{
String driverName1 = "oracle.jdbc.driver.OracleDriver";
Class.forName(driverName1);
String serverName = "localhost";
String portNumber = "1521";
String sid = "XE";
String url = "jdbc:oracle:thin:@" + serverName + ":" + portNumber + ":" + sid;
String username = "SYSTEM";
String password = "password";
connection1 = DriverManager.getConnection(url, username, password);
out.println(connection1.isClosed());
String Name = request.getParameter("name");
String Age = request.getParameter("age");
int AgeConvert = Integer.parseInt(Age);
String ADR = request.getParameter("address");
String sqlInsert = " INSERT INTO ADDRESS (NAME,AGE,ADR) VALUES ('" + Name + "' , " + AgeConvert + ", '" + ADR +"')";
Statement stm = connection1.createStatement();
stm.execute(sqlInsert);
out.println(" User Created");
}
catch(Exception e )
{
out.println("User not created");
e.printStackTrace();
}
%>
<table>
<tr>
<td> <b>To search the User Please enter the name in the below box </b> </td>
</tr>
<tr>
<td> Name </td>
<td> <input type = "text" name ="userName" /> </td>
</tr>
<tr>
<td> <input type ="submit" value = "Search" /></td>
</tr>
</table>
<% ResultSet results = null ;
String userNameToBeSearched = request.getParameter("userName");
String sqlselect = " SELECT * FROM ADDRESS WHERE NAME ='"+userNameToBeSearched+"'";
Statement stm2 = connection1.createStatement();
results = stm2.execute(sqlselect);
**// getting error in this loop it says can convert boolean to ResultSet please help me**
if (results.next()) {
do {
%>
<TABLE BORDER="1">
<TR>
<TH>Name</TH>
<TH>Age</TH>
<TH>Address</TH>
</TR>
<TR>
<TD> <%= results.getString(1) %> </TD>
<TD> <%= results.getInt(2) %> </TD>
<TD> <%= results.getString(3) %> </TD>
</TR>
</TABLE>
<%
} while (results.next());
} else
{
out.println("User not found");
}
%>
</body>
</html>
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%@page import="java.sql.*"%><%@page import = "java.sql.ResultSet" %>
<%@page import = "java.sql.Connection" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Getting Database Connection</title>
</head>
<body>
<%
ResultSet result = null ;
Connection connection1 = null;
try
{
String driverName1 = "oracle.jdbc.driver.OracleDriver";
Class.forName(driverName1);
String serverName = "localhost";
String portNumber = "1521";
String sid = "XE";
String url = "jdbc:oracle:thin:@" + serverName + ":" + portNumber + ":" + sid;
String username = "SYSTEM";
String password = "password";
connection1 = DriverManager.getConnection(url, username, password);
out.println(connection1.isClosed());
String Name = request.getParameter("name");
String Age = request.getParameter("age");
int AgeConvert = Integer.parseInt(Age);
String ADR = request.getParameter("address");
String sqlInsert = " INSERT INTO ADDRESS (NAME,AGE,ADR) VALUES ('" + Name + "' , " + AgeConvert + ", '" + ADR +"')";
Statement stm = connection1.createStatement();
stm.execute(sqlInsert);
out.println(" User Created");
}
catch(Exception e )
{
out.println("User not created");
e.printStackTrace();
}
%>
<table>
<tr>
<td> <b>To search the User Please enter the name in the below box </b> </td>
</tr>
<tr>
<td> Name </td>
<td> <input type = "text" name ="userName" /> </td>
</tr>
<tr>
<td> <input type ="submit" value = "Search" /></td>
</tr>
</table>
<% ResultSet results = null ;
String userNameToBeSearched = request.getParameter("userName");
String sqlselect = " SELECT * FROM ADDRESS WHERE NAME ='"+userNameToBeSearched+"'";
Statement stm2 = connection1.createStatement();
results = stm2.execute(sqlselect);
**// getting error in this loop it says can convert boolean to ResultSet please help me**
if (results.next()) {
do {
%>
<TABLE BORDER="1">
<TR>
<TH>Name</TH>
<TH>Age</TH>
<TH>Address</TH>
</TR>
<TR>
<TD> <%= results.getString(1) %> </TD>
<TD> <%= results.getInt(2) %> </TD>
<TD> <%= results.getString(3) %> </TD>
</TR>
</TABLE>
<%
} while (results.next());
} else
{
out.println("User not found");
}
%>
</body>
</html>
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评论（4）
如果光标位于第一行之前，isBeforeFirst() 返回 true；如果光标位于任何其他位置或结果集不包含行，则为 false
isBeforeFirst() returns true if the cursor is before the first row; false if the cursor is at any other position or the result set contains no rows
尝试 stm2.exexuteQuery()
这将获取结果集
try stm2.exexuteQuery()
This will grab the result set
如果没有找到更多行，
ResultSet.next()返回false，否则返回true。ResultSet.next()returnsfalseif no more rows are found, otherwisetrue.这样做不行吗：
.next() 将遍历行并验证是否有行。
Would it not work doing:
.next() will go through the rows and validate if there is any row.