Java 使用Hadoop自定义数据类型时出现EOF异常
我是第一次在Hadoop中使用自定义数据类型。这是我的密码: 自定义数据类型:Java 使用Hadoop自定义数据类型时出现EOF异常,java,hadoop,mapreduce,Java,Hadoop,Mapreduce,我是第一次在Hadoop中使用自定义数据类型。这是我的密码: 自定义数据类型: public class TwitterData implements Writable { private Long id; private String text; private Long createdAt; public TwitterData(Long id, String text, Long createdAt) { super(); this.id = id; this.
public class TwitterData implements Writable {
private Long id;
private String text;
private Long createdAt;
public TwitterData(Long id, String text, Long createdAt) {
super();
this.id = id;
this.text = text;
this.createdAt = createdAt;
}
public TwitterData() {
this(new Long(0L), new String(), new Long(0L));
}
@Override
public void readFields(DataInput in) throws IOException {
System.out.println("In readFields...");
id = in.readLong();
text = in.readLine();
createdAt = in.readLong();
}
@Override
public void write(DataOutput out) throws IOException {
System.out.println("In write...");
out.writeLong(id);
out.writeChars(text);
out.writeLong(createdAt);
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getText() {
return text;
}
public void setText(String text) {
this.text = text;
}
public Long getCreatedAt() {
return createdAt;
}
public void setCreatedAt(Long createdAt) {
this.createdAt = createdAt;
}
}
制图员:
public class Map extends Mapper<Object, BSONObject, Text, TwitterData>{
@Override
public void map(Object key, BSONObject value, Context context) throws IOException, InterruptedException {
BSONObject user = (BSONObject) value.get("user");
String location = (String) user.get("location");
TwitterData twitterData = new TwitterData((Long) value.get("id"),
(String) value.get("text"), (Long) value.get("createdAt"));
if(location.toLowerCase().indexOf("india") != -1) {
context.write(new Text("India"), twitterData);
} else {
context.write(new Text("Other"), twitterData);
}
}
}
我在映射过程之后抛出这个异常。我不明白为什么它会显示这个错误。谁能帮帮我吗。
提前谢谢。你写字符,你读行。这是两个不同的序列化过程 您需要做的是:
@Override
public void readFields(DataInput in) throws IOException {
id = in.readLong();
text = in.readUTF();
createdAt = in.readLong();
}
@Override
public void write(DataOutput out) throws IOException {
out.writeLong(id);
out.writeUTF(text);
out.writeLong(createdAt);
}
谢谢你,托马斯。我为我工作。那么,如果没有writeLine(),readLine()有什么用处呢?例如,当您从文本文件读取并逐行读取时,writeChars()..@AbhendraSingh的情况也类似。写一行就是写UTF+'\n'。
@Override
public void readFields(DataInput in) throws IOException {
id = in.readLong();
text = in.readUTF();
createdAt = in.readLong();
}
@Override
public void write(DataOutput out) throws IOException {
out.writeLong(id);
out.writeUTF(text);
out.writeLong(createdAt);
}