Idea中flume的Interceptor的编写教程

1.新建-项目-新建项目

注意位置是将来打包文件存放的位置，即我们打包好的文件在这/export/data个目录下寻找

2. 在maven项目中导入依赖

Pom.xml文件中写入

<groupId>org.apache.flume</groupId>

<artifactId>flume-ng-core</artifactId>

</dependency>

</dependencies>

3.创建包（scr-main-java右键-新建-软件包）

4.创建Java类（右键包名-新建-java类）

5. 继承（implements)flume 的拦截器接口

//键入implements Interceptor{} 光标定位到Interceptor alt + enter键选择导入类导入flume的Interceptor即可 import org.apache.flume.interceptor.Interceptor;

//此时会报错，点击红色灯泡，选择实现方法就会在下文写出需要Override的四个抽象类

6.实现方法

public class MyInterceptor implements Interceptor {

    @Override

    //初始化方法

    public void initialize() {


    }

//单个事件拦截

//需求：在event的头部信息中添加标记

 //提供给channel selector 选择发送给不同的channel



    @Override

public Event intercept(Event event)

       //Map也需要alt + enter 导入

        Map<String, String> headers = event.getHeaders();

        //输入even.getHeaders().var回车即可自行填充等号前面的变量信息

        String log = new String(event.getBody());

        //envent.getBody().var自行判断变量类型为byte,为方便使用改为String类型

        // 键入new String(envent.getBody()).var回车，然后根据需要自行修改变量名

        //判断log开头的第一个字符，字母则发到channel1，数字则发到channel2

        char c = log.charAt(0);

        //log.charAt(0).var回车即可自行填充等号前面的变量信息

        if(c >= '0' && c <= '9'){

            headers.put("type","number");

        }else if ((c >= 'A' && c<= 'Z') || (c >= 'a' && c <= 'z')){

            // 注意字符串类型要使用>=需要用单引号而不能用双引号

            headers.put("type","letter");

        }

        //因为头部信息属性是一个引用数据类型 直接修改对象即可，也可以不调用以下的set方法   

        event.setHeaders(headers);

        //返回event

        return event;

    }

    //批量事件拦截(处理多个event,系统调用这个方法)

    @Override

    public List<Event> intercept(List<Event> list) {



        for (Event event : list){

            intercept(event);

        }

        return list;

    }



//重写静态内部类Builder

    @Override

    public void close() {


}

public static class  Builder implements Interceptor.Builder{

       //创建一个拦截器对象

        @Override

        public Interceptor build() {

            return new MyInterceptor();

        }

       //配置方法

        @Override

        public void configure(Context context) {


        }

    }

}

7.打包（idea右侧菜单栏maven-生命周期-package）

打包完成在idea左侧菜单栏 target 中可以看到我们的包

8.将建好的包复制到flume家目录下的lib中即可使用

cp /export/data/flume-interceptor-demo/target/flume-interceptor-demo-1.0-SNAPSHOT.jar $FLUME_HOME/lib

9.测试

9.1 编辑 flume 配置文件

vim flume1.conf

|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| # agent a1.sources = r1 a1.sinks = k1 k2 a1.channels = c1 c2 # Describe/configure the source a1.sources.r1.type = netcat a1.sources.r1.bind = node1 a1.sources.r1.port = 44444 # channel selector: multiplexing 多路复用；默认为replicating 复制 a1.sources.r1.selector.type = multiplexing # 填写相应inerceptor的header上的key a1.sources.r1.selector.header = type # 分配不同value发送到的channel,number到c2，letter到 c1 a1.sources.r1.selector.mapping.number = c2 a1.sources.r1.selector.mapping.letter = c1 #如果匹配不上默认选择的channel a1.sources.r1.selector.default = c2 #interceptor a1.sources.r1.interceptors = i1 a1.sources.r1.interceptors.i1.type = com.ljr.flume.MyInterceptor$Builder # Describe the sink a1.sinks.k1.type = avro a1.sinks.k1.hostname = node1 a1.sinks.k1.port = 4545 a1.sinks.k2.type = avro a1.sinks.k2.hostname = node1 a1.sinks.k2.port = 4546 # Use a channel which buffers events in memory a1.channels.c1.type = memory a1.channels.c1.capacity = 1000 a1.channels.c1.transactionCapacity = 100 a1.channels.c2.type = memory a1.channels.c2.capacity = 1000 a1.channels.c2.transactionCapacity = 100 # Bind the source and sink to the channel a1.sources.r1.channels = c1 c2 # 接收c1中的数据 a1.sinks.k1.channel = c1 # 接收c2中的数据 a1.sinks.k2.channel = c2 |

vim flume2.conf

vim flume3.conf

9.2测试

打开四个窗口，前三个分别运行flume1.conf、flume2.conf、flume3.conf 配置的进程

第四个窗口启用necat,输入内容进行测试

flume-ng agent -c conf/ -f /export/server/flume/job/group2-multiplexing-test/flume1.conf -n a1

flume-ng agent -c conf/ -f /export/server/flume/job/group2-multiplexing-test/flume2.conf -n a2

flume-ng agent -c conf/ -f /export/server/flume/job/group2-multiplexing-test/flume3.conf -n a3

nc nc node1 44444 (flume1.conf中 source 填的主机名或IP地址和端口号)

第一个窗口报错 ConnectException: 拒绝连接可先忽略，运行二、三窗口后即可连接

在窗口4中输入数字、字母、符号

分别在窗口二看到输出字母，窗口三输出数字和符号

恭喜，Interceptor起作用！