由于底层异常导致通信链接失败：java.net.ConnectException：连接被拒绝：连接

时间：2015-07-29 20:54:56

标签： java sql

我一直在寻找SOF的答案，但无论我做什么都行不通。我见过类似于我的问题，所以请不要发表评论，说这已经得到了回答。正如我之前所说，我发现以前的答案对我不起作用。

基本上我只是搞乱SQL并决定制作一个简单的程序来保存我''商店'中的所有“客户”。这是Store.java（Main class）的代码

import java.util.UUID;

import com.galanjulio.store.customers.Customer;
import com.galanjulio.store.sql.SQL;

public class Store {

public static void main(String[] args){

    System.out.println("============================");

    SQL sql = new SQL();
    sql.checkTable();

    System.out.println("============================");

    Customer c = new Customer();
    c.setName("Tom");
    c.setUniqueId(UUID.randomUUID());
    c.setCredits(0);

    sql.addToDatabase(c);

}

这是我的SQL.java类

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;

import com.galanjulio.store.customers.Customer;

public class SQL {

private Connection con;
private Statement st = null;

private String connectionString = 
"jdbc:mysql://167.114.67.166:3306/store?user=user&password=pass";

public void checkTable(){
    String query = "CREATE TABLE IF NOT EXISTS `customers` (uuid VARCHAR(36), name VARCHAR(15), credits INT);";
    try{
        Class.forName("com.mysql.jdbc.Driver");
        con = DriverManager.getConnection(connectionString);
        st = con.createStatement();
        st.executeUpdate(query);
        System.out.println("Database created successfully...");
     }catch(SQLException se){
        //Handle errors for JDBC
        System.out.println(se.getMessage());
     }catch(Exception e){
        //Handle errors for Class.forName
         e.printStackTrace();
     }finally{
        //finally block used to close resources
        try{
           if(st != null)
              st.close();
        }catch(SQLException se2){
        }// nothing we can do
        try{
           if(con != null)
              con.close();
        }catch(SQLException se){
            System.out.println(se.getMessage());
        }//end finally try
     }//end try
}

public void addToDatabase(Customer c){
    String query = "INSERT INTO `customers` (uuid, name, credits) VALUES (" + c.getUniqueId() + ", " + c.getName() + ", " + c.getCredits() + ");";

    try{
    Class.forName("com.mysql.jdbc.Driver");
    con = DriverManager.getConnection(connectionString);
    st = con.createStatement();
    st.executeUpdate(query);
    System.out.println("Added " + c.getName() + " to the database");
 }catch(SQLException se){
    //Handle errors for JDBC
     System.out.println(se.getMessage());
 }catch(Exception e){
    //Handle errors for Class.forName
     System.out.println("Class.forName has thrown an exception!");
 }finally{
    //finally block used to close resources
    try{
       if(st!=null)
          st.close();
    }catch(SQLException se2){
    }// nothing we can do
    try{
       if(con != null)
          con.close();
    }catch(SQLException se){
        System.out.println(se.getMessage());
    }//end finally try
 }//end try
}

这是我得到的错误

Communications link failure due to underlying exception: 

** BEGIN NESTED EXCEPTION ** 

java.net.ConnectException
MESSAGE: Connection refused: connect

STACKTRACE:

java.net.ConnectException: Connection refused: connect
    at java.net.DualStackPlainSocketImpl.connect0(Native Method)
    at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)
    at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
    at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
    at java.net.AbstractPlainSocketImpl.connect(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:256)
    at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:271)
    at com.mysql.jdbc.Connection.createNewIO(Connection.java:2771)
    at com.mysql.jdbc.Connection.<init>(Connection.java:1555)
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:285)
    at java.sql.DriverManager.getConnection(Unknown Source)
    at java.sql.DriverManager.getConnection(Unknown Source)
    at com.galanjulio.store.sql.SQL.checkTable(SQL.java:26)
    at com.galanjulio.store.Store.main(Store.java:15)


** END NESTED EXCEPTION **



Last packet sent to the server was 0 ms ago.
============================
Communications link failure due to underlying exception: 

** BEGIN NESTED EXCEPTION ** 

java.net.ConnectException
MESSAGE: Connection refused: connect

STACKTRACE:

java.net.ConnectException: Connection refused: connect
    at java.net.DualStackPlainSocketImpl.connect0(Native Method)
    at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)
    at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
    at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
    at java.net.AbstractPlainSocketImpl.connect(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:256)
    at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:271)
    at com.mysql.jdbc.Connection.createNewIO(Connection.java:2771)
    at com.mysql.jdbc.Connection.<init>(Connection.java:1555)
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:285)
    at java.sql.DriverManager.getConnection(Unknown Source)
    at java.sql.DriverManager.getConnection(Unknown Source)
    at com.galanjulio.store.sql.SQL.addToDatabase(SQL.java:57)
    at com.galanjulio.store.Store.main(Store.java:24)


** END NESTED EXCEPTION **



Last packet sent to the server was 0 ms ago.

这是我在SOF上提出的第一个问题，抱歉如果格式不正确。 感谢您的帮助！

1 个答案:

答案 0 :(得分：1)

我的第一个猜测是＆＃34;防火墙＆＃34;。无论是在您身边，在您的服务器方面，还是两者兼而有之。

检查的一种方法是查看任何客户端是否可以从PC连接到删除服务器。例如，＆＃34; telnet SERVERNAME 3306＆＃34;。或者从PC上试用mySQL客户端。

我的第二个猜测是，一旦您完全验证了TCP / IP级连接，就是mySQL权限。

看这里：

请注意＆＃34;拨款＆＃34;可以申请＆＃34; db资源＆＃34; +＆＃34; db user＆＃34; +＆＃34; db客户端主机＆＃34;。

还要注意＆＃34; mySQL权限＆＃34;通常导致不同的错误，而不是＆＃34;连接被拒绝＆＃34;。再次 - 检查您的主机名，检查您的防火墙，验证网络连接。

＆＃39;希望有所帮助！

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