本文为您介绍MapReduce的分区表输入示例。
- 示例一:
public static void main(String[] args) throws Exception { JobConf job = new JobConf(); ... LinkedHashMap<String, String> input = new LinkedHashMap<String, String>(); input.put("pt", "123456"); InputUtils.addTable(TableInfo.builder().tableName("input_table").partSpec(input).build(), job); LinkedHashMap<String, String> output = new LinkedHashMap<String, String>(); output.put("ds", "654321"); OutputUtils.addTable(TableInfo.builder().tableName("output_table").partSpec(output).build(), job); JobClient.runJob(job); }
- 示例二:
package com.aliyun.odps.mapred.open.example; ... public static void main(String[] args) throws Exception { if (args.length != 2) { System.err.println("Usage: WordCount <in_table> <out_table>"); System.exit(2); } JobConf job = new JobConf(); job.setMapperClass(TokenizerMapper.class); job.setCombinerClass(SumCombiner.class); job.setReducerClass(SumReducer.class); job.setMapOutputKeySchema(SchemaUtils.fromString("word:string")); job.setMapOutputValueSchema(SchemaUtils.fromString("count:bigint")); Account account = new AliyunAccount("my_access_id", "my_access_key"); Odps odps = new Odps(account); odps.setEndpoint("odps_endpoint_url"); odps.setDefaultProject("my_project"); Table table = odps.tables().get(tblname); TableInfoBuilder builder = TableInfo.builder().tableName(tblname); for (Partition p : table.getPartitions()) { if (applicable(p)) { LinkedHashMap<String, String> partSpec = new LinkedHashMap<String, String>(); for (String key : p.getPartitionSpec().keys()) { partSpec.put(key, p.getPartitionSpec().get(key)); } InputUtils.addTable(builder.partSpec(partSpec).build(), job); } } OutputUtils.addTable(TableInfo.builder().tableName(args[1]).build(), job); JobClient.runJob(job); }
说明
- 上述示例是使用MaxCompute SDK和MapReduce SDK组合实现MapReduce任务读取范围分区的示例。
- 此段代码不能够编译执行,仅给出了main函数的示例。
- 示例中applicable函数是用户逻辑,用于决定该分区是否可以作为MapReduce作业的输入。