我现在尝试了 12 个小时从我的数据库中选择数据，但我做不到。
插入工作正常。只是 SELECT 不起作用。
当我运行 connect() 函数时，我收到很多错误:
public void connect() {
String dbUrl = "jdbc:mysql://*****.heliohost.org:3306/*****";
try
{
Class.forName("com.mysql.jdbc.Driver");
connection = DriverManager.getConnection(dbUrl,"*****","****");
return;//the debugger never succeed to reach this line
} catch (Exception e) {
e.printStackTrace();
}
}
我从上面的 connect() 函数得到的错误:
12-23 16:22:54.460: W/dalvikvm(7473): VFY: unable to find class referenced in signature (Ljavax/naming/Reference;)
12-23 16:22:54.470: I/dalvikvm(7473): Could not find method javax.naming.Reference.get, referenced from method com.mysql.jdbc.ConnectionPropertiesImpl$ConnectionProperty.initializeFrom
12-23 16:22:54.470: W/dalvikvm(7473): VFY: unable to resolve virtual method 14440: Ljavax/naming/Reference;.get (Ljava/lang/String;)Ljavax/naming/RefAddr;
12-23 16:22:54.470: D/dalvikvm(7473): VFY: replacing opcode 0x6e at 0x0004
12-23 16:22:54.491: W/dalvikvm(7473): VFY: unable to find class referenced in signature (Ljavax/naming/Reference;)
12-23 16:22:54.491: E/dalvikvm(7473): Could not find class 'javax.naming.StringRefAddr', referenced from method com.mysql.jdbc.ConnectionPropertiesImpl$ConnectionProperty.storeTo
12-23 16:22:54.491: W/dalvikvm(7473): VFY: unable to resolve new-instance 1365 (Ljavax/naming/StringRefAddr;) in Lcom/mysql/jdbc/ConnectionPropertiesImpl$ConnectionProperty;
12-23 16:22:54.491: D/dalvikvm(7473): VFY: replacing opcode 0x22 at 0x0006
下一个函数仅在到达以下行时才会下降:“String tem = result.getString("name")":
public List<String> selectCategories()
{
List<String> listCS = new ArrayList<String>();
try
{
Statement statement = connection.createStatement();
statement.execute("select name from categories");
ResultSet result=statement.getResultSet();
if(result!=null)
{
while(result.next());
{
String tem = result.getString("name");
listCS.add(tem);
}//end of while
}//end of if
}//end of try
catch(java.sql.SQLException e)
{
e.printStackTrace();
}
return listCS;
}
最佳答案
第一个函数的错误表明您正在使用 JNDI 命名资源来获取连接，而不是来自 DriverManager 的资源。
您确定设备可以看到该主机和端口吗？设备是否有连接权限？ MySQL数据库中的GRANT是什么样的？
您从类别表中获取名称的方法也不好。您不会在finally block 中关闭任何资源。你应该。
那些 //end of while 和 //end of if 注释是令人发指的。它们不会添加信息，只会造成困惑。从您的代码中删除这些内容。
关于java - sql 连接错误 - 阻止我从 mysql 获取 'SELECT' 数据，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/20744054/