jdbc连接mySQL报com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communic
这是代码:public class MySQLAccess {
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/feedback?"
+ "user=test&password=123");
// 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 FEEDBACK.COMMENTS");
writeResultSet(resultSet);
// PreparedStatements can use variables and are more efficient
preparedStatement = connect
.prepareStatement("insert into FEEDBACK.COMMENTS values (default, ?, ?, ?, ? , ?, ?)");
// "myuser, webpage, datum, summery, COMMENTS from FEEDBACK.COMMENTS");
// Parameters start with 1
preparedStatement.setString(1, "Test");
preparedStatement.setString(2, "TestEmail");
preparedStatement.setString(3, "TestWebpage");
preparedStatement.setDate(4, new java.sql.Date(2009, 12, 11));
preparedStatement.setString(5, "TestSummary");
preparedStatement.setString(6, "TestComment");
preparedStatement.executeUpdate();
preparedStatement = connect
.prepareStatement("SELECT myuser, webpage, datum, summery, COMMENTS from FEEDBACK.COMMENTS");
resultSet = preparedStatement.executeQuery();
writeResultSet(resultSet);
// Remove again the insert comment
preparedStatement = connect
.prepareStatement("delete from FEEDBACK.COMMENTS where myuser= ? ; ");
preparedStatement.setString(1, "Test");
preparedStatement.executeUpdate();
resultSet = statement
.executeQuery("select * from FEEDBACK.COMMENTS");
writeMetaData(resultSet);
} catch (Exception e) {
throw e;
} finally {
close();
}
}
Exception in thread "main" 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(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:406)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1074)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2214)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:781)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:46)
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:406)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:352)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:284)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at Test.example.MySQLAccess.readDataBase(MySQLAccess.java:23)
at Test.test.Test.main(Test.java:6)
Caused by: 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(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:406)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1074)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:343)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2137)
... 13 more
Caused by: java.net.ConnectException: connect: Address is invalid on local machine, or port is not valid on remote machine
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(Unknown Source)
at java.net.PlainSocketImpl.connectToAddress(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:253)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:292)
... 14 more
这报错让我不知所措啊```初学数据库``````希望大虾们能帮忙解决一下``
[ 本帖最后由 cqxooo 于 2009-11-16 01:55 编辑 ]
搜索更多相关主题的帖子:
mysql mySQL exceptions Communic jdbc
----------------解决方案--------------------------------------------------------
mySQL的驱动包加载一下
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回复 楼主 cqxooo
加载过了``` ----------------解决方案--------------------------------------------------------
我没连mySQL,但按你报错来看,要么是Driver错了,要么是包有问题
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