Question

这是堆栈跟踪：

 java.sql.SQLException
 at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:290)
at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:182)
at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:702)
at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:634)
at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:488)
at org.apache.tomcat.jdbc.pool.ConnectionPool.<init>(ConnectionPool.java:144)
at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:116)
at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:103)
at org.apache.tomcat.jdbc.pool.DataSourceProxy.getConnection(DataSourceProxy.java:127)
at com.boeing.DBReader.Server.makeConnection(Server.java:85)
at com.boeing.DBReader.Server.<init>(Server.java:26)
at com.boeing.DBReader.Reader.main(Reader.java:13)
Caused by: java.lang.NullPointerException
at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:395)
at   org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:278)
... 11 more
Connection closed

以下是代码：

公共类服务器 {

private DataSource datasource;


public Server()
{
    try
    {
        createConnectionToDatabase();
    } catch (Exception e)
    {
        // TODO Auto-generated catch block
        System.out.println("Exception:" + e.toString());
    }
    makeConnection();
}

private void createConnectionToDatabase() throws Exception 
{
String connectionString = null;
String login = null;
String password = null;

System.out.println("In createConnectionToDatabase");

PoolProperties p = new PoolProperties();
p.setUrl("jdbc:oracle:thin:@***");

p.setUrl(connectionString);
p.setDriverClassName("oracle.jdbc.OracleDriver");
p.setUsername("**");
p.setPassword("**");

p.setJmxEnabled(true);
p.setTestWhileIdle(false);
p.setTestOnBorrow(true);
p.setValidationQuery("SELECT 1 from dual");
p.setTestOnReturn(false);
p.setValidationInterval(30000);
p.setTimeBetweenEvictionRunsMillis(30000);
p.setMaxActive(100);
p.setInitialSize(10);
p.setMaxWait(10000);
p.setRemoveAbandonedTimeout(600);
p.setMinEvictableIdleTimeMillis(30000);
p.setMinIdle(10);
p.setLogAbandoned(true);
p.setRemoveAbandoned(true);
p.setJdbcInterceptors("org.apache.tomcat.jdbc.pool.interceptor.ConnectionState;"
        + "org.apache.tomcat.jdbc.pool.interceptor.StatementFinalizer");

datasource = new DataSource();
datasource.setPoolProperties(p);


}

private void closeConnection(Connection con) {
    if (con != null) {
        try {
            con.close();
        } catch (Exception ignore) {
            System.out.println("Could not close connection, WTF?");
        }
    }
}

private void makeConnection()
{
    Connection con = null;
    String queryString = "SQL QUERY GOES HERE ";
    try {
        System.out.println("Connection attempt");
        con = datasource.getConnection();

        System.out.println("Connection made no issues");

    } catch (Exception e) {
        System.out.println("Exception:" + e.toString());
        e.printStackTrace();
    } finally {
        closeConnection(con);
        System.out.println("Connection closed");
    }


}

我将驱动程序附加到构建路径上。我做错了什么？这是在没有maven的情况下设置的，只是一个普通的java项目。

谢谢！

Answer 1

从堆栈跟踪中不完全确定，但这看起来不对：

String connectionString = null;
String login = null;
String password = null;

System.out.println("In createConnectionToDatabase");

PoolProperties p = new PoolProperties();
p.setUrl("jdbc:oracle:thin:@***");

p.setUrl(connectionString);

您将网址设置为connectionString，该网址为空。

连接到oracle DataBase时，我得到nullpointerexception

1 个答案: