读取properties文件,连接数据库与金典的查询方法（返回list）

package write_demo;

import java.io.File;

import java.io.FileInputStream;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.ResultSetMetaData;

import java.sql.SQLException;

import java.sql.Statement;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import java.util.Properties;

public class JDBCUtils {

/**

* 连接数据库

* */

public static Connection getConnection() throws Exception {

//读取jdbc.properties文件,获取数据库信息
Properties info = new Properties();
info.load(new FileInputStream(new File("jdbc.properties")));

String url = info.getProperty("url");
String driverClass = info.getProperty("driverClass");
String user = info.getProperty("user");
String password = info.getProperty("password");

//加载驱动

Class.forName(driverClass);

//连接数据库

Connection conn = DriverManager.getConnection(url, user, password);

return conn;

}

/**

* 关闭数据库连接对象

* */

public static void close(ResultSet rs,Statement st,Connection conn){

if(rs != null){

try {

rs.close();

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

if(st != null){

try {

st.close();

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

if(conn != null){

try {

conn.close();

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

}

/**
* 金典查询
* */
@SuppressWarnings("unchecked")
public static List select(String sql) {
Statement stat = null;
ResultSet rs = null;
ResultSetMetaData rsmd = null;
java.sql.Connection conOrcale = null;
List ll = new ArrayList();
try {
conOrcale = JDBCUtils.getConnection();
stat = conOrcale.createStatement();
// 得到结果集
rs = stat.executeQuery(sql);
// 用于获取关于 ResultSet 对象中列的类型和属性信息的对象
rsmd = rs.getMetaData();
while (rs.next()) {
try {
Map rowData = new HashMap();
for (int i = 1; i <= rsmd.getColumnCount(); i++)
rowData.put(rsmd.getColumnName(i), rs.getString(i));
ll.add(rowData);
} catch (Exception e) {
e.printStackTrace();
}
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
conOrcale.close();
stat.close();
rs.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return ll;
}

//测试jdbc是否连接成功

@SuppressWarnings("unchecked")

public static void main(String[] args) throws Exception {

//System.out.println(getConnection());

List list = select("select * from h_hyjx_yellowpages");

for (Object obj : list) {

System.out.println(obj);

}

}

}