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使用资源示例

更新时间:2017-06-07 13:26:11   分享:   

(1)准备好测试程序jar包,假设名字为mapreduce-examples.jar;

(2)准备好测试表和资源;

  • 创建表

    create table mr_upload_src(key bigint, value string);
    
  • 添加资源

    add jar mapreduce-examples.jar -f;
    add file import.txt -f;
    
  • import.txt数据内容:

    1000,odps

测试步骤

在odpscmd中执行Upload

jar -resources mapreduce-examples.jar,import.txt -classpath mapreduce-examples.jar
    com.aliyun.odps.mapred.open.example.Upload import.txt mr_upload_src;

预期结果

作业成功结束。 输出表mr_upload_src中内容为:

+------------+------------+
| key        | value      |
+------------+------------+
| 1000       | odps       |
+------------+------------+

代码示例

    package com.aliyun.odps.mapred.open.example;

    import java.io.BufferedInputStream;
    import java.io.FileNotFoundException;
    import java.io.IOException;


    import com.aliyun.odps.data.Record;
    import com.aliyun.odps.data.TableInfo;
    import com.aliyun.odps.mapred.JobClient;
    import com.aliyun.odps.mapred.MapperBase;
    import com.aliyun.odps.mapred.TaskContext;
    import com.aliyun.odps.mapred.conf.JobConf;
    import com.aliyun.odps.mapred.utils.InputUtils;
    import com.aliyun.odps.mapred.utils.OutputUtils;
    import com.aliyun.odps.mapred.utils.SchemaUtils;

    /**
     * Upload
     *
     * Import data from text file into table
     *
     **/
    public class Upload {

      public static class UploadMapper extends MapperBase {
        @Override
        public void setup(TaskContext context) throws IOException {
          Record record = context.createOutputRecord();
          StringBuilder importdata = new StringBuilder();
          BufferedInputStream bufferedInput = null;

          try {
            byte[] buffer = new byte[1024];
            int bytesRead = 0;

            String filename = context.getJobConf().get("import.filename");
            bufferedInput = context.readResourceFileAsStream(filename);

            while ((bytesRead = bufferedInput.read(buffer)) != -1) {
              String chunk = new String(buffer, 0, bytesRead);
              importdata.append(chunk);
            }

            String lines[] = importdata.toString().split("\n");
            for (int i = 0; i < lines.length; i++) {
              String[] ss = lines[i].split(",");
              record.set(0, Long.parseLong(ss[0].trim()));
              record.set(1, ss[1].trim());
              context.write(record);
            }
          } catch (FileNotFoundException ex) {
            throw new IOException(ex);
          } catch (IOException ex) {
            throw new IOException(ex);
          } finally {
          }

        }

        @Override
        public void map(long recordNum, Record record, TaskContext context)
            throws IOException {

        }

      }

      public static void main(String[] args) throws Exception {
        if (args.length != 2) {
          System.err.println("Usage: Upload <import_txt> <out_table>");
          System.exit(2);
        }

        JobConf job = new JobConf();

        job.setMapperClass(UploadMapper.class);

        job.set("import.filename", args[0]);

        job.setNumReduceTasks(0);

        job.setMapOutputKeySchema(SchemaUtils.fromString("key:bigint"));
        job.setMapOutputValueSchema(SchemaUtils.fromString("value:string"));

        InputUtils.addTable(TableInfo.builder().tableName("mr_empty").build(), job);
        OutputUtils.addTable(TableInfo.builder().tableName(args[1]).build(), job);

        JobClient.runJob(job);
      }

    }

实际上用户有多种手段设置JobConf:

  • 通过SDK中JobConf的接口设置,本示例即是通过此方法。此方法的优先级最高;
  • 在jar命令行中通过–conf参数指定新的JobConf文件。此种方式的优先级最低。–conf的使用方式请参考 运行命令 ;
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