mysql データベースをストレージとして使用して独自の CRM (Customer Relationship Manager) アプリケーションを構築しています。テーブルが表示されるように、Eclipse Java プロジェクトをデータベースにリンクしようとしています。私はこのコードを実行しようとしています:
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
//import java.util.Date;
public class MySQLclass{
private Connection connect = null;
private Statement statement = null;
private PreparedStatement preparedStatement = null;
private ResultSet resultSet = null;
public void readDataBase() throws Exception {
try {
// This will load the MySQL driver, each DB has its own driver
Class.forName("com.mysql.jdbc.Driver");
// Setup the connection with the DB
connect = DriverManager
.getConnection("jdbc:mysql://localhost/test"
+ "user=root&password=password");
// Statements allow to issue SQL queries to the database
statement = connect.createStatement();
// Result set get the result of the SQL query
resultSet = statement
.executeQuery("select * from test.customers");
writeResultSet(resultSet);
// PreparedStatements can use variables and are more efficient
preparedStatement = connect
.prepareStatement("insert into test.customers values (default, ?, ?, ?, ? , ?, ?, ?)");
// "myuser, webpage, datum, summary, customers from test.customers");
// Parameters start with 1
preparedStatement.setString(1, "Sjaakie Sjaakssen");
preparedStatement.setString(2, "Sjaakssen@yahoo.nl");
preparedStatement.setString(3, "pannekoekenstraat 2");
preparedStatement.setString(4, "Rotterdam");
preparedStatement.setString(5, "3022PK");
preparedStatement.setString(6, "0101235489");
preparedStatement.setString(7, "Yahoo");
preparedStatement.executeUpdate();
preparedStatement = connect
.prepareStatement("SELECT NAAM, EMAIL, TELEFOON, BEDRIJFSNAAM, customers from test.customers");
resultSet = preparedStatement.executeQuery();
writeResultSet(resultSet);
// Remove again the insert comment
preparedStatement = connect
.prepareStatement("delete from test.customers where NAAM= ? ; ");
preparedStatement.setString(1, "Test");
preparedStatement.executeUpdate();
resultSet = statement
.executeQuery("select * from test.customers");
writeMetaData(resultSet);
} catch (Exception e) {
throw e;
} finally {
close();
}
}
private void writeMetaData(ResultSet resultSet) throws SQLException {
// Now get some metadata from the database
// Result set get the result of the SQL query
System.out.println("The columns in the table are: ");
System.out.println("Table: " + resultSet.getMetaData().getTableName(1));
for (int i = 1; i<= resultSet.getMetaData().getColumnCount(); i++){
System.out.println("Column " +i + " "+ resultSet.getMetaData().getColumnName(i));
}
}
private void writeResultSet(ResultSet resultSet) throws SQLException {
// ResultSet is initially before the first data set
while (resultSet.next()) {
// It is possible to get the columns via name
// also possible to get the columns via the column number
// which starts at 1
// e.g. resultSet.getSTring(2);
String Naam = resultSet.getString("naam");
String Email = resultSet.getString("email");
String Adres = resultSet.getString("adres");
String plaats = resultSet.getString("plaats");
String Postcode = resultSet.getString("postcode");
String Telefoon = resultSet.getString("telefoon");
String Bedrijfsnaam = resultSet.getString("bedrijfsnaam");
System.out.println("Naam: " + Naam);
System.out.println("Email: " + Email);
System.out.println("Adres: " + Adres);
System.out.println("plaats: " + plaats);
System.out.println("Postcode: " + Postcode);
System.out.println("Telefoon:" + Telefoon);
System.out.println("Bedrijfsnaam" + Bedrijfsnaam);
}
}
// You need to close the resultSet
private void close() {
try {
if (resultSet != null) {
resultSet.close();
}
if (statement != null) {
statement.close();
}
if (connect != null) {
connect.close();
}
} catch (Exception e) {
}
}
}
このメインクラスで：
public class Main {
public static void main(String[] args) throws Exception {
MySQLclass dao = new MySQLclass();
dao.readDataBase();
}
}
そして、私はこのエラーを受け取り続けます:
Exception in thread "main" java.sql.SQLException: Access denied for user ''@'localhost' (using password: NO)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1078)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4187)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4119)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:927)
at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1709)
at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1252)
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2483)
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2516)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2301)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:834)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:416)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:346)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at MySQLclass.readDataBase(MySQLclass.java:22)
at Main.main(Main.java:5)
誰かが私のジレンマに光を当ててくれませんか。