使用 Beam 从 oracle 获取 JDBC

本文介绍了使用 Beam 从 oracle 获取 JDBC的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

限时送ChatGPT账号..

下面的程序是连接到 Oracle 11g 并获取记录.它是如何为我在 pipeline.apply() 处的编码器提供 NullPointerException 的.

The below program is to connect to Oracle 11g and fetch the records. How ever it is giving me NullPointerException for the coder at pipeline.apply().

我已将 ojdbc14.jar 添加到项目依赖项中.

I have added the ojdbc14.jar to the project dependencies.

public static void main(String[] args) {

        Pipeline p = Pipeline.create(PipelineOptionsFactory.create());      
         p.apply(JdbcIO.<KV<Integer, String>>read()
                   .withDataSourceConfiguration(JdbcIO.DataSourceConfiguration.create(
                          "oracle.jdbc.driver.OracleDriver", "jdbc:oracle:thin:@hostdnsname:port/servicename")
                   .withUsername("uname")
                   .withPassword("pwd"))
                   .withQuery("select EMPID,NAME from EMPLOYEE1")
                   .withRowMapper(new JdbcIO.RowMapper<KV<Integer, String>>() {
                     public KV<Integer, String> mapRow(ResultSet resultSet) throws Exception {
                       return KV.of(resultSet.getInt(1), resultSet.getString(2));
                     }
                   }));
         p.run();

    }

出现以下错误.有任何线索吗?

is giving the below error.Any clue?

Exception in thread "main" java.lang.NullPointerException: coder
    at com.googlemon.base.Preconditions.checkNotNull(Preconditions.java:228)
    at org.apache.beam.sdk.io.jdbc.JdbcIO$Read.validate(JdbcIO.java:283)
    at org.apache.beam.sdk.io.jdbc.JdbcIO$Read.validate(JdbcIO.java:216)
    at org.apache.beam.sdk.Pipeline.applyInternal(Pipeline.java:399)
    at org.apache.beam.sdk.Pipeline.applyTransform(Pipeline.java:307)
    at org.apache.beam.sdk.values.PBegin.apply(PBegin.java:47)
    at org.apache.beam.sdk.Pipeline.apply(Pipeline.java:158)
    at org.apache.beam.examples.v030.JdbcUtil.main(JdbcUtil.java:21)

推荐答案

你好！

对不起，错误信息不是很有帮助，但实际上它是一个验证步骤.我已提交 BEAM-959 以改进这一点.

Sorry the error message is not very helpful, but in fact it is a validation step. I have filed BEAM-959 to improve this.

您需要提供诸如via之类的编码器

You are required to provide a coder such as via

.withCoder(KvCoder.of(VarIntCoder.of(), StringUtf8Coder.of())`

我已提交 BEAM-960 以改进此编码器的自动化，就像我们在 Beam 的大多数其他地方一样.

I have filed BEAM-960 to improve automation of this coder, like we have in most other places in Beam.

这篇关于使用 Beam 从 oracle 获取 JDBC的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！