java - 静态类中的 IO 异常 - java

Question

public class classifyTweet {

  public static class MapClass 
          extends Mapper<LongWritable, Text, Text, Text> {

  static final Configuration conf = new Configuration();

  protected void map(LongWritable key, Text value, Context context) 
             throws IOException, InterruptedException {

  StandardNaiveBayesClassifier classifier = new StandardNaiveBayesClassifier(NaiveBayesModel.materialize(new Path(modelPath), conf));

    }
  }
 }

我只想初始化分类器变量一次，materialize 方法抛出 IOEception，如果我在 map 方法之外声明它并且喜欢配置对象初始化，它会给出 IOException 的编译错误。如何只初始化一次？

Answer 1

制作 StandardNaiveBayesClassifier - 单例

public class StandardNaiveBayesClassifier {
private static StandardNaiveBayesClassifier instance;

public static StandardNaiveBayesClassifier getInstance(... you params) {
    if (instance == null)
        instance = new StandardNaiveBayesClassifier();
    return instance;
}

private StandardNaiveBayesClassifier() {
}