<p>我正在嘗試連接到本地 MySQL 服務(wù)器，但不斷收到錯(cuò)誤消息。</p> <p>這是代碼。</p> <pre class="brush:php;toolbar:false;">public class Connect { public static void main(String[] args) { Connection conn = null; try { String userName = "myUsername"; String password = "myPassword"; String url = "jdbc:mysql://localhost:3306/myDatabaseName"; Class.forName("com.mysql.jdbc.Driver").newInstance(); conn = DriverManager.getConnection(url, userName, password); System.out.println("Database connection established"); } catch (Exception e) { System.err.println("Cannot connect to database server"); System.err.println(e.getMessage()); e.printStackTrace(); } finally { if (conn != null) { try { conn.close(); System.out.println("Database Connection Terminated"); } catch (Exception e) {} } } } }</pre> <p>以及錯(cuò)誤：</p> <pre class="brush:php;toolbar:false;">Cannot connect to database server Communications link failure The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server. com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server. at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27) at java.lang.reflect.Constructor.newInstance(Constructor.java:513) at com.mysql.jdbc.Util.handleNewInstance(Util.java:411) at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1116) at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:344) at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2333) at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2370) at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2154) at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:792) at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27) at java.lang.reflect.Constructor.newInstance(Constructor.java:513) at com.mysql.jdbc.Util.handleNewInstance(Util.java:411) at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:381) at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:305) at java.sql.DriverManager.getConnection(DriverManager.java:582) at java.sql.DriverManager.getConnection(DriverManager.java:185) at Connect.main(Connect.java:16) Caused by: java.net.ConnectException: Connection refused at java.net.PlainSocketImpl.socketConnect(Native Method) at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:351) at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:213) at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:200) at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366) at java.net.Socket.connect(Socket.java:529) at java.net.Socket.connect(Socket.java:478) at java.net.Socket.<init>(Socket.java:375) at java.net.Socket.<init>(Socket.java:218) at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:257) at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:294) ... 15 more</pre> <p>我已經(jīng)設(shè)置了類路徑，確保 my.cnf 已注釋掉跳過網(wǎng)絡(luò)選項(xiàng)。 </p> <p>java版本是1.2.0_26（64位） mysql 5.5.14 mysql連接器5.1.17</p> <p>我確保用戶有權(quán)訪問我的數(shù)據(jù)庫。</p>