需求： 1、按照文件中的第一列排序。 2、如果第一列相同，则按照第二列排序 准备数据： 1 5 2 4 3 6 1 3 2 1
首先自定义二次排序key
代码语言：javascript复制/**
* 自定义的二次排序key
* @author Administrator
*
*/
public class SecondarySortKey implements Ordered<SecondarySortKey>, Serializable {
private static final long serialVersionUID = -2366006422945129991L;
// 首先在自定义key里面，定义需要进行排序的列
private int first;
private int second;
public SecondarySortKey(int first, int second) {
this.first = first;
this.second = second;
}
@Override
public boolean $greater(SecondarySortKey other) {
if(this.first > other.getFirst()) {
return true;
} else if(this.first == other.getFirst() &&
this.second > other.getSecond()) {
return true;
}
return false;
}
@Override
public boolean $greater$eq(SecondarySortKey other) {
if(this.$greater(other)) {
return true;
} else if(this.first == other.getFirst() &&
this.second == other.getSecond()) {
return true;
}
return false;
}
@Override
public boolean $less(SecondarySortKey other) {
if(this.first < other.getFirst()) {
return true;
} else if(this.first == other.getFirst() &&
this.second < other.getSecond()) {
return true;
}
return false;
}
@Override
public boolean $less$eq(SecondarySortKey other) {
if(this.$less(other)) {
return true;
} else if(this.first == other.getFirst() &&
this.second == other.getSecond()) {
return true;
}
return false;
}
@Override
public int compare(SecondarySortKey other) {
if(this.first - other.getFirst() != 0) {
return this.first - other.getFirst();
} else {
return this.second - other.getSecond();
}
}
@Override
public int compareTo(SecondarySortKey other) {
if(this.first - other.getFirst() != 0) {
return this.first - other.getFirst();
} else {
return this.second - other.getSecond();
}
}
// 为要进行排序的多个列，提供getter和setter方法，以及hashcode和equals方法
public int getFirst() {
return first;
}
public void setFirst(int first) {
this.first = first;
}
public int getSecond() {
return second;
}
public void setSecond(int second) {
this.second = second;
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result first;
result = prime * result second;
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
SecondarySortKey other = (SecondarySortKey) obj;
if (first != other.first)
return false;
if (second != other.second)
return false;
return true;
}
}
/**
* 二次排序
* 1、实现自定义的key，要实现Ordered接口和Serializable接口，在key中实现自己对多个列的排序算法
* 2、将包含文本的RDD，映射成key为自定义key，value为文本的JavaPairRDD
* 3、使用sortByKey算子按照自定义的key进行排序
* 4、再次映射，剔除自定义的key，只保留文本行
* @author Administrator
*
*/
public class SecondarySort {
public static void main(String[] args) {
SparkConf conf = new SparkConf().setAppName("SecondarySort").setMaster("local");
JavaSparkContext sc = new JavaSparkContext(conf);
JavaRDD<String> lines = sc.textFile("C://Users//Administrator//Desktop//sort.txt");
JavaPairRDD<SecondarySortKey, String> pairs = lines.mapToPair(
new PairFunction<String, SecondarySortKey, String>() {
private static final long serialVersionUID = 1L;
@Override
public Tuple2<SecondarySortKey, String> call(String line) throws Exception {
String[] lineSplited = line.split(" ");
SecondarySortKey key = new SecondarySortKey(
Integer.valueOf(lineSplited[0]),
Integer.valueOf(lineSplited[1]));
return new Tuple2<SecondarySortKey, String>(key, line);
}
});
JavaPairRDD<SecondarySortKey, String> sortedPairs = pairs.sortByKey();
JavaRDD<String> sortedLines = sortedPairs.map(
new Function<Tuple2<SecondarySortKey,String>, String>() {
private static final long serialVersionUID = 1L;
@Override
public String call(Tuple2<SecondarySortKey, String> v1) throws Exception {
return v1._2;
}
});
sortedLines.foreach(new VoidFunction<String>() {
private static final long serialVersionUID = 1L;
@Override
public void call(String t) throws Exception {
System.out.println(t);
}
});
sc.close();
}
}Scala版本
代码语言：javascript复制/**
* @author Administrator
*/
class SecondSortKey(val first: Int, val second: Int) extendsOrdered[SecondSortKey] with Serializable {
def compare(that: SecondSortKey): Int = {
if(this.first - that.first != 0) {
this.first - that.first
} else {
this.second - that.second
}
}
}SecondSort.scala
代码语言：javascript复制import org.apache.spark.SparkConf
import org.apache.spark.SparkContext
object SecondSort {
def main(args: Array[String]): Unit = {
val conf = new SparkConf().setAppName("SecondSort").setMaster("local")
val sc = new SparkContext(conf)
val lines = sc.textFile("C://Users//Administrator//Desktop//sort.txt", 1)
val pairs = lines.map { line => (
new SecondSortKey(line.split(" ")(0).toInt, line.split(" ")(1).toInt),
line)}
val sortedPairs = pairs.sortByKey()
val sortedLines = sortedPairs.map(sortedPair => sortedPair._2)
sortedLines.foreach { sortedLine => println(sortedLine) }
}
}
