The following examples use partitioned tables as the input of a MapReduce job.
Example 1
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);
}
Example 2
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(), conf);
}
}
OutputUtils.addTable(TableInfo.builder().tableName(args[1]).build(), job);
JobClient.runJob(job);
}
Note
- The preceding examples demonstrate how to use the MaxCompute SDK and MapReduce SDK to implement a MapReduce task that is used to read data from specific partitions.
- The preceding code cannot be compiled for execution. It is only an example of the main function.
- The applicable function is user logic that determines whether the partition can be used as the input of a MapReduce job.