1.多路径输入

1）FileInputFormat.addInputPath 多次调用加载不同路径

FileInputFormat.addInputPath(job, new Path("hdfs://RS5-112:9000/cs/path1"));
FileInputFormat.addInputPath(job, new Path("hdfs://RS5-112:9000/cs/path2"));

2）FileInputFormat.addInputPaths一次调用加载 多路径字符串用逗号隔开

FileInputFormat.addInputPaths(job, "hdfs://RS5-112:9000/cs/path1,hdfs://RS5-112:9000/cs/path2");

2.多种输入

MultipleInputs可以加载不同路径的输入文件，并且每个路径可用不同的maper

MultipleInputs.addInputPath(job, new Path("hdfs://RS5-112:9000/cs/path1"), TextInputFormat.class,MultiTypeFileInput1Mapper.class);

MultipleInputs.addInputPath(job, new Path("hdfs://RS5-112:9000/cs/path3"), TextInputFormat.class,MultiTypeFileInput3Mapper.class);

例子：

package example;
import Java.io.IOException;
import org.apache.Hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.input.MultipleInputs;
import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
/**
 * 多类型文件输入
 * @author lijl
 *
 */
public class MultiTypeFileInputMR {
static class MultiTypeFileInput1Mapper extends Mapper<LongWritable, Text, Text, Text>{
public void map(LongWritable key,Text value,Context context){
try {
String[] str = value.toString().split("\\|");
context.write(new Text(str[0]), new Text(str[1]));
} catch (IOException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
static class MultiTypeFileInput3Mapper extends Mapper<LongWritable, Text, Text, Text>{
public void map(LongWritable key,Text value,Context context){
try {
String[] str = value.toString().split("");
context.write(new Text(str[0]), new Text(str[1]));
} catch (IOException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
static class MultiTypeFileInputReducer extends Reducer<Text, Text, Text, Text>{
public void reduce(Text key,Iterable<Text> values,Context context){
try {
for(Text value:values){
context.write(key,value);
}

} catch (IOException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
public static void main(String[] args) throws IOException, InterruptedException, ClassNotFoundException {
Configuration conf = new Configuration();
conf.set("mapred.textoutputformat.separator", ",");
Job job = new Job(conf,"MultiPathFileInput");
job.setJarByClass(MultiTypeFileInputMR.class);
FileOutputFormat.setOutputPath(job, new Path("hdfs://RS5-112:9000/cs/path6"));
job.setMapOutputKeyClass(Text.class);
job.setMapOutputValueClass(Text.class);
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(Text.class);
job.setReducerClass(MultiTypeFileInputReducer.class);
job.setNumReduceTasks(1);
MultipleInputs.addInputPath(job, new Path("hdfs://RS5-112:9000/cs/path1"), TextInputFormat.class,MultiTypeFileInput1Mapper.class);
MultipleInputs.addInputPath(job, new Path("hdfs://RS5-112:9000/cs/path3"), TextInputFormat.class,MultiTypeFileInput3Mapper.class);
System.exit(job.waitForCompletion(true)?0:1);
}
}

本文转自博客园知识天地的博客，原文链接：mapreduce 多种输入，如需转载请自行联系原博主。