[学习笔记]
1.sql server的helloworld例子：
import java.sql.*;
public class JdbcHelloSqlServer {
public static void main(String[] args) {
String dbUrl= "jdbc:jtds:sqlserver://localhost:1433/Northwind";String user = "sa";String password = "1234";
// String dbUrl="jdbc:mysql://localhost:3306/test"; String user = "root";String password = "1234";
String createString;
Statement stmt;
createString = "select * from orders";
try {
/*this method attempts to locate, load,
and link the class or interface. The specified class loader is
used to load the class or interface. If the parameter loader is
null, the class is loaded through the bootstrap class loader.
about soundBlaster driver?when you talk to the microphone, it can
record into the computer and save as a file. your sound is
transfered into 01 signal and save as a file. all these are done by driver.
the same thing, using DB? you also need driver.
*/
Class.forName("net.sourceforge.jtds.jdbc.Driver");
// Class.forName("com.mysql.jdbc.Driver");
/* When the method
getConnection is called, the DriverManager will attempt to
locate a suitable driver from amongst those loaded at initialization
*/
Connection con = DriverManager.getConnection(dbUrl, user, password);
System.out.println("Connection is ok");
/* Statement object is a workspace to create SQL queries, execute them, and retrieve any results that are returned.
tube has track,vehicle is on the track for coal. vehicle is only suitable for this track , not for any other track.
*/
stmt = con.createStatement();
// stmt.execute(createString);
/* Resultset object contains the table produced by the SQL query
*/
ResultSet rs = stmt.executeQuery(createString);
System.out.println("qixybefore");
//获得元数据
//获得元数据
ResultSetMetaData meta = rs.getMetaData();
for (int i = 1; i <= meta.getColumnCount(); i++) {
if (meta.getColumnType(i) == java.sql.Types.INTEGER) { // if it is CHAR
System.out.println("Types.INTEGER is " +i +" " + meta.getColumnName(i)); // display the name
}
System.out.println(meta.getColumnName(i)); //字段名称
}
System.out.println("qixylater");
/*boolean next() throws SQLException Moves the cursor down one row from its current position. A ResultSet cursor is initially
positioned before the first row; the first call to the method next makes the first row the current row; the second call makes
the second row the current row, and so on. Returns:true if the new current row is valid; false if there are no more rows */
while (rs.next()) {
文章转载自原文：https://blog.csdn.net/qq_44594249/article/details/100764762