自定义排序 WritableComparable

publicclassFlowBeanSortimplementsWritableComparable<FlowBeanSort> {
privatelongupFlow;     // 上行总流量privatelongdownFlow;  // 下行总流量privatelongsumFlow;  // 总流量    ...
// 自定义排序规则，按照总流量倒序排序@OverridepublicintcompareTo(FlowBeanSorto) {
// 自定义降序排列returnthis.sumFlow>o.getSumFlow() ?-1 : 1;
    }
}

ackagecom.xiaowang.mr.sort;
importjava.io.DataInput;
importjava.io.DataOutput;
importjava.io.IOException;
importorg.apache.hadoop.io.WritableComparable;
/*** 自定义一个 bean 类，实现 WritableComparable 接口重写 compareTo()方法，实现自定义排序* * @author Administrator**/publicclassFlowBeanSortimplementsWritableComparable<FlowBeanSort> {
privatelongupFlow; // 总上行流量privatelongdownFlow; // 总下行流量privatelongsumFlow; // 总流量// 无参构造方法必须有，目的是为了在反序列化操作创建对象实例时调用无参构造器publicFlowBeanSort() {
super();
    }
// 序列化方法，目的是为了对象的初始化publicFlowBeanSort(longupFlow, longdownFlow, longsumFlow) {
super();
this.upFlow=upFlow;
this.downFlow=downFlow;
this.sumFlow=sumFlow;
    }
publiclonggetUpFlow() {
returnupFlow;
    }
publicvoidsetUpFlow(longupFlow) {
this.upFlow=upFlow;
    }
publiclonggetDownFlow() {
returndownFlow;
    }
publicvoidsetDownFlow(longdownFlow) {
this.downFlow=downFlow;
    }
publiclonggetSumFlow() {
returnsumFlow;
    }
publicvoidsetSumFlow(longsumFlow) {
this.sumFlow=sumFlow;
    }
// 序列化方法，将对象的字段信息写入输出流@Overridepublicvoidwrite(DataOutputout) throwsIOException {
out.writeLong(upFlow);
out.writeLong(downFlow);
out.writeLong(sumFlow);
    }
// 反序列化方法，从输入流中读取各个字段信息// 注意：字段的反序列化顺序需要和序列化的顺序保持一致，而且字段的类型和个数也要保持一致@OverridepublicvoidreadFields(DataInputin) throwsIOException {
this.upFlow=in.readLong();
this.downFlow=in.readLong();
this.sumFlow=in.readLong();
    }
// 实现自定义排序，按照总流量倒序排序@OverridepublicintcompareTo(FlowBeanSorto) {
// 自定义降序排列returnthis.sumFlow>o.getSumFlow() ?-1 : 1;
    }
// 重写toString()方法@OverridepublicStringtoString() {
returnupFlow+"\t"+downFlow+"\t"+sumFlow;
    }
}