本文为您介绍基于MaxCompute Studio通过Java UDTF读取MaxCompute资源的使用示例。
前提条件
已安装MaxCompute Studio,并连接至MaxCompute项目,创建了MaxCompute Java Module。
更多操作信息,请参见安装MaxCompute Studio、管理项目连接和创建MaxCompute Java Module。
更多MaxCompute资源信息,请参见资源。
UDTF代码示例
package com.aliyun.odps.examples.udf;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.Iterator;
import com.aliyun.odps.udf.ExecutionContext;
import com.aliyun.odps.udf.UDFException;
import com.aliyun.odps.udf.UDTF;
import com.aliyun.odps.udf.annotation.Resolve;
/**
* project: example_project
* table: wc_in2
* partitions: p2=1,p1=2
* columns: colc,colb
*/
@Resolve("string,string->string,bigint,string")
public class UDTFResource extends UDTF {
ExecutionContext ctx;
long fileResourceLineCount;
long tableResource1RecordCount;
long tableResource2RecordCount;
@Override
public void setup(ExecutionContext ctx) throws UDFException {
this.ctx = ctx;
try {
InputStream in = ctx.readResourceFileAsStream("file_resource.txt");
BufferedReader br = new BufferedReader(new InputStreamReader(in));
String line;
fileResourceLineCount = 0;
while ((line = br.readLine()) != null) {
fileResourceLineCount++;
}
br.close();
Iterator<Object[]> iterator = ctx.readResourceTable("table_resource1").iterator();
tableResource1RecordCount = 0;
while (iterator.hasNext()) {
tableResource1RecordCount++;
iterator.next();
}
iterator = ctx.readResourceTable("table_resource2").iterator();
tableResource2RecordCount = 0;
while (iterator.hasNext()) {
tableResource2RecordCount++;
iterator.next();
}
} catch (IOException e) {
throw new UDFException(e);
}
}
@Override
public void process(Object[] args) throws UDFException {
String a = (String) args[0];
long b = args[1] == null ? 0 : ((String) args[1]).length();
forward(a, b, "fileResourceLineCount=" + fileResourceLineCount + "|tableResource1RecordCount="
+ tableResource1RecordCount + "|tableResource2RecordCount=" + tableResource2RecordCount);
}
}