flume 拦截器

目的：功能1：判断json文件，如何格式合格则正常传输，否则就不传输

功能2：判断出合格的json文件，并且key值中包含“date”才进行传输

一、创建一个Json的工具类

package com.atguigu.gmall.flume.utils;
import com.alibaba.fastjson.JSONObject;
import org.apache.flume.Event;
 
public class JSONUtil {
//    public static void main(String[] args) {
//        String log = "{date:2}";
//        String key = "date";
//        System.out.println(isJSONValidate(log));
//        System.out.println(isContainsKey(log, key));
////        System.out.println(JSONObject.parseObject(log).containsKey(key));
//    }
 
//    判断log是否为一个合法的json
    public static boolean isJSONValidate(String log) {
        try {
            JSONObject.parseObject(log);  //是将str转化为相应的JSONObject对象
            return true;
        } catch (Exception e) {
//            e.printStackTrace();
            return false;
        }
    }
 
    //  判断json中是否包含key值，其中如果log不是合格的json，直接走异常返回false
    public static boolean isContainsKey(String log,String key){
        try {
            if (JSONObject.parseObject(log).containsKey(key)) {
                return true;
            } else{
                return  false;
            }
        } catch (Exception e) {
//            e.printStackTrace();
            return false;
        }
    }
}

　　二、编写拦截器，只需要重写Event intercept和List<Event> intercept方法即可。如果传输的json文件不是很复杂，只需要重写单个event的intercept方法即可

package com.atguigu.gmall.flume.intercepter;
 
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;
import com.atguigu.gmall.flume.utils.JSONUtil;
import org.apache.flume.Context;
import org.apache.flume.Event;
import org.apache.flume.interceptor.Interceptor;
 
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
 
public class ETLIntercepter implements Interceptor {
    @Override
    public void initialize() {
    }
 
    @Override
        public Event intercept(Event event) {
//        获取body中的数据
        byte[] body = event.getBody();
        String log= new String(body, StandardCharsets.UTF_8);
//        1.判断是否为合法的json，是：返回event ， 否：返回null
//        if(JSONUtil.isJSONValidate(log ){
//            return event;
//        }else{
//            return null;
//        }
//        2.判断是否为合法的json，且是都包含key值“date”
        if(JSONUtil.isContainsKey(log,"date") ){
            return event;
        }else{
            return null;
        }
    }
 
    @Override
    public List<Event> intercept(List<Event> list) {
//        判断事件list中的event是都合格，如果不合格就将event的删掉，返回合格的event列表
//        如果list中的event都不合格，则返回null
        Iterator<Event> iterator = list.iterator();
        while(iterator.hasNext()){
            Event event = iterator.next();
            if(intercept(event) == null){
                iterator.remove();
            }
        }
        return list;
    }
 
    @Override
    public void close() {
    }
 
    public static  class Builder implements Interceptor.Builder{
        @Override
        public Interceptor build() {
            return new ETLIntercepter();
        }
        @Override
        public void configure(Context context) {
        }
    }
}

三、生成rtProj-1.0-SNAPSHOT-jar-with-dependencies.jar包上传到flume的lib目录下，然后再编辑flume的配置文件

a1.sources = r1
a1.channels = c1
  
# Describe/configure the source
a1.sources.r1.type = taildir
a1.sources.r1.filegroups=f1
a1.sources.r1.filegroups.f1 = /workplace/data/log*.*
a1.sources.r1.positionFile  = /workplace/data/taildir_position.json   
a1.sources.r1.interceptors = i1
a1.sources.r1.interceptors.i1.type = com.atguigu.gmall.flume.intercepter.ETLIntercepter$Builder 
#i1.type :此地址是拦截器中Builder的地址（右键点击Copy Reference,记得将.Builder中的 . 换成$号）
  
# Use a channel which buffers events in memory
a1.channels.c1.type = org.apache.flume.channel.kafka.KafkaChannel
a1.channels.c1.kafka.bootstrap.servers=master:9092
a1.channels.c1.kafka.topic = test1
  
# Bind the source and sink to the channel
a1.sources.r1.channels = c1