需求
1、对原始json数据进行解析,变成普通文本数据
2、求出每个人评分最高的3部电影
3、求出被评分次数最多的3部电影
数据
https://pan.baidu.com/s/1gPsQXVYSQEZ2OYek4HxK6A
pom.xml
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.cyf</groupId> <artifactId>MapReduceCases</artifactId> <packaging>jar</packaging> <version>1.0</version> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> </properties> <dependencies> <dependency> <groupId>org.apache.hadoop</groupId> <artifactId>hadoop-common</artifactId> <version>2.6.4</version> </dependency> <dependency> <groupId>org.apache.hadoop</groupId> <artifactId>hadoop-hdfs</artifactId> <version>2.6.4</version> </dependency> <dependency> <groupId>org.apache.hadoop</groupId> <artifactId>hadoop-client</artifactId> <version>2.6.4</version> </dependency> <dependency> <groupId>org.apache.hadoop</groupId> <artifactId>hadoop-mapreduce-client-core</artifactId> <version>2.6.4</version> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>fastjson</artifactId> <version>1.1.40</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.36</version> </dependency> </dependencies> <build> <plugins> <plugin> <artifactId>maven-assembly-plugin</artifactId> <configuration> <appendAssemblyId>false</appendAssemblyId> <descriptorRefs> <descriptorRef>jar-with-dependencies</descriptorRef> </descriptorRefs> <archive> <manifest> <mainClass>cn.itcast.mapreduce.json.JsonToText</mainClass> </manifest> </archive> </configuration> <executions> <execution> <id>make-assembly</id> <phase>package</phase> <goals> <goal>assembly</goal> </goals> </execution> </executions> </plugin> </plugins> </build> </project>
package cn.itcast.mapreduce.json; import java.io.DataInput; import java.io.DataOutput; import java.io.IOException; import org.apache.hadoop.io.NullWritable; import org.apache.hadoop.io.WritableComparable; public class OriginBean implements WritableComparable<OriginBean> { private Long movie; private Long rate; private Long timeStamp; private Long uid; public Long getMovie() { return movie; } public void setMovie(Long movie) { this.movie = movie; } public Long getRate() { return rate; } public void setRate(Long rate) { this.rate = rate; } public Long getTimeStamp() { return timeStamp; } public void setTimeStamp(Long timeStamp) { this.timeStamp = timeStamp; } public Long getUid() { return uid; } public void setUid(Long uid) { this.uid = uid; } public OriginBean(Long movie, Long rate, Long timeStamp, Long uid) { this.movie = movie; this.rate = rate; this.timeStamp = timeStamp; this.uid = uid; } public OriginBean() { // TODO Auto-generated constructor stub } public int compareTo(OriginBean o) { return this.movie.compareTo(o.movie); } public void write(DataOutput out) throws IOException { out.writeLong(movie); out.writeLong(rate); out.writeLong(timeStamp); out.writeLong(uid); } public void readFields(DataInput in) throws IOException { this.movie = in.readLong(); this.rate = in.readLong(); this.timeStamp = in.readLong(); this.uid = in.readLong(); } @Override public String toString() { return this.movie + " " + this.rate + " " + this.timeStamp + " " + this.uid; } }
package cn.itcast.mapreduce.json; 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.NullWritable; 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.output.FileOutputFormat; import org.apache.hadoop.mapreduce.lib.output.SequenceFileOutputFormat; import org.codehaus.jackson.map.ObjectMapper; import com.alibaba.fastjson.JSON; import com.alibaba.fastjson.JSONObject; public class JsonToText { static class MyMapper extends Mapper<LongWritable, Text, Text, NullWritable> { Text k = new Text(); @Override protected void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException { // Bean bean = mapper.readValue(value.toString(), Bean.class); JSONObject valueJson = JSON.parseObject(value.toString()); Long movie = valueJson.getLong("movie"); OriginBean bean = new OriginBean(movie, valueJson.getLong("rate"), valueJson.getLong("timeStamp"), valueJson.getLong("uid")); k.set(bean.toString()); context.write(k, NullWritable.get()); } } public static void main(String[] args) throws Exception { Configuration conf = new Configuration();
//16777216/1024/1024=16 (62.5M/16)4个切片,启动4个maptask,处理结果4个文件
conf.set("mapreduce.input.fileinputformat.split.maxsize", "16777216"); Job job = Job.getInstance(conf); // job.setJarByClass(JsonToText.class); //告诉框架,我们的程序所在jar包的位置 job.setJar("/root/JsonToText.jar"); job.setMapperClass(MyMapper.class); job.setOutputKeyClass(Text.class); job.setOutputValueClass(NullWritable.class); // job.setOutputFormatClass(SequenceFileOutputFormat.class); job.setNumReduceTasks(0); FileInputFormat.setInputPaths(job, new Path("/json/input")); FileOutputFormat.setOutputPath(job, new Path("/json/output")); // FileInputFormat.setInputPaths(job, new Path(args[0])); // FileOutputFormat.setOutputPath(job, new Path(args[1])); job.waitForCompletion(true); } }
创建文件夹 并上传数据
hadoop fs -mkdir -p /json/input
hadoop fs -put rating.json /json/input
运行
hadoop jar JsonToText.jar cn.itcast.mapreduce.json.JsonToText
运行结果
https://pan.baidu.com/s/1ayrpl7w8Dlzpc7TRZIO94w
pom.xml
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.cyf</groupId> <artifactId>MapReduceCases</artifactId> <packaging>jar</packaging> <version>1.0</version> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> </properties> <dependencies> <dependency> <groupId>org.apache.hadoop</groupId> <artifactId>hadoop-common</artifactId> <version>2.6.4</version> </dependency> <dependency> <groupId>org.apache.hadoop</groupId> <artifactId>hadoop-hdfs</artifactId> <version>2.6.4</version> </dependency> <dependency> <groupId>org.apache.hadoop</groupId> <artifactId>hadoop-client</artifactId> <version>2.6.4</version> </dependency> <dependency> <groupId>org.apache.hadoop</groupId> <artifactId>hadoop-mapreduce-client-core</artifactId> <version>2.6.4</version> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>fastjson</artifactId> <version>1.1.40</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.36</version> </dependency> </dependencies> <build> <plugins> <plugin> <artifactId>maven-assembly-plugin</artifactId> <configuration> <appendAssemblyId>false</appendAssemblyId> <descriptorRefs> <descriptorRef>jar-with-dependencies</descriptorRef> </descriptorRefs> <archive> <manifest> <mainClass>cn.itcast.mapreduce.json.MovieRateSum</mainClass> </manifest> </archive> </configuration> <executions> <execution> <id>make-assembly</id> <phase>package</phase> <goals> <goal>assembly</goal> </goals> </execution> </executions> </plugin> </plugins> </build> </project>
package cn.itcast.mapreduce.json; import java.io.DataInput; import java.io.DataOutput; import java.io.IOException; import org.apache.hadoop.io.WritableComparable; public class ResultBean implements WritableComparable<ResultBean> { private Long movie; private Long sumRate; public void setSumRate(long sumRate) { this.sumRate = sumRate; } public Long getMovie() { return movie; } public void setMovie(Long movie) { this.movie = movie; } public ResultBean(Long movie, Long sumRate) { this.movie = movie; this.sumRate = sumRate; } public ResultBean() { // TODO Auto-generated constructor stub } public int compareTo(ResultBean o) { if (this.movie - o.movie != 0) { return (int) (this.movie - o.movie); } return (int) (o.sumRate - this.sumRate); } public void write(DataOutput out) throws IOException { out.writeLong(movie); out.writeLong(sumRate); } public ResultBean(Long sumRate) { super(); this.sumRate = sumRate; } public void readFields(DataInput in) throws IOException { this.movie = in.readLong(); this.sumRate = in.readLong(); } @Override public String toString() { //return movie + " " + sumRate; return movie + " " + sumRate; } }
package cn.itcast.mapreduce.json; 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.NullWritable; 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.output.FileOutputFormat; import org.apache.hadoop.mapreduce.lib.output.SequenceFileOutputFormat; import org.codehaus.jackson.map.ObjectMapper; import com.alibaba.fastjson.JSON; import com.alibaba.fastjson.JSONObject; public class MovieRateSum { static class MyMapper extends Mapper<LongWritable, Text, LongWritable, OriginBean> { ObjectMapper mapper = new ObjectMapper(); @Override protected void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException { // Bean bean = mapper.readValue(value.toString(), Bean.class); JSONObject valueJson = JSON.parseObject(value.toString()); Long movie = valueJson.getLong("movie"); OriginBean bean = new OriginBean(movie, valueJson.getLong("rate"), valueJson.getLong("timeStamp"), valueJson.getLong("uid")); context.write(new LongWritable(bean.getMovie()), bean); } } static class MyReduce extends Reducer<LongWritable, OriginBean, ResultBean, NullWritable> { @Override protected void reduce(LongWritable movie, Iterable<OriginBean> beans, Context context) throws IOException, InterruptedException { long sum = 0L; for (OriginBean bean : beans) { sum += bean.getRate(); } ResultBean bean = new ResultBean(); bean.setMovie(movie.get()); bean.setSumRate(sum); context.write(bean, NullWritable.get()); } } public static void main(String[] args) throws Exception { Configuration conf = new Configuration(); Job job = Job.getInstance(conf); // job.setJarByClass(MovieRateSum.class); //告诉框架,我们的程序所在jar包的位置 job.setJar("/root/MovieRateSum.jar"); job.setMapperClass(MyMapper.class); job.setReducerClass(MyReduce.class); job.setMapOutputKeyClass(LongWritable.class); job.setMapOutputValueClass(OriginBean.class); job.setOutputKeyClass(ResultBean.class); job.setOutputValueClass(NullWritable.class); job.setOutputFormatClass(SequenceFileOutputFormat.class); FileInputFormat.setInputPaths(job, new Path("/json/output")); FileOutputFormat.setOutputPath(job, new Path("/json/output-seq")); // FileInputFormat.setInputPaths(job, new Path(args[0])); // FileOutputFormat.setOutputPath(job, new Path(args[1])); job.waitForCompletion(true); } }