package DBUtil;
import java.sql.Connection;
import java.sql.Statement;
import java.sql.ResultSet;
import java.sql.SQLException;
import javax.sql.DataSource;
import javax.naming.Context;
import javax.naming.InitialContext;
public class DBConnection {
private Connection conn = null;
private Statement stmt = null;
private ResultSet rs = null;
private int resultNum = 0;
/**
* 构造函数
* 找到数据源，并用这个数据源创建连接
*/
public DBConnection() {
try {
Context ctx = new InitialContext();
if (ctx == null) throw new Exception("No Context");
DataSource ds = (DataSource)ctx.lookup("java:comp/env/jdbc/oracle");
if (ds == null) throw new Exception("jdbc/oracle is an unknown DataSource");
conn = ds.getConnection();
stmt = conn.createStatement();
} catch (Exception e) {
System.out.println("naming:" + e.getMessage());
}
}
/**
* 执行SQL语句：查询记录
* @param sql SQL语句
* @return ResultSet 记录集
*/
public ResultSet executeQuery(String sql) {
rs = null;
try {
rs = stmt.executeQuery(sql);
} catch(SQLException se) {
System.out.println("Query error:" + se.getMessage());
}
return rs;
}
/**
* 执行SQL语句 ：插入与更新记录
* @param sql SQL语句
* @return int resultNum 更新的记录数
*/
public int executeUpdate(String sql) {
resultNum=0;
try {
resultNum = stmt.executeUpdate(sql);
} catch (SQLException se) {
System.err.println("Update error:" + se.getMessage());
}
return resultNum;
}
/**
* 关闭连接
*/
public void close() {
try {
if (rs != null) {
rs.close();
rs = null;
}
if (stmt != null) {
stmt.close();
stmt = null;
}
if (conn != null) {
conn.close();
conn = null;
}
} catch (SQLException se) {
System.out.println("close error:" + se.getMessage());
}
}
} 
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