如何将Classifier与ClassifierCompositeItemWriter结合使用? [英] How to use Classifier with ClassifierCompositeItemWriter?

问题描述

在实现ClassifierCompositeItemwriter时遇到麻烦...

have trouble implementing a ClassifierCompositeItemwriter...

我正在读取基本的CSV文件，我想将其写入数据库. 根据数据(名称+名称1)将其写入简单的ItemWriter或使用CompositeItemwriter(写入两个不同的表)...

I am reading a basic CSV File and i want to write them do a database. Depending on the data (Name + Name1) either write it to a simple ItemWriter or use a compositeItemwriter (that writes to two different Tables)...

这是我的: ClassifierCompositeItemwriter 参见>下面的错误消息

This is my : ClassifierCompositeItemwriter see > Error Message below

public ClassifierCompositeItemWriter<MyObject> classifierCompositeItemWriter() {
ClassifierCompositeItemWriter<MyObject> writer = new ClassifierCompositeItemWriter<MyObject>();
writer.setClassifier(new MySpecialClassifier());
return writer;
}

我尝试使用分类器接口

import org.springframework.batch.item.ItemWriter;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.classify.Classifier;

@SuppressWarnings("serial")
public class MySpecialClassifier implements Classifier<MyObject, ItemWriter<MyObject>> {

@Autowired
ItemWriter<MyObject> writer1;

@Autowired
ItemWriter<MyObject> writer2;

@Override
public ItemWriter<MyObject> classify(MyObject obj) {

    if (!obj.getName().isEmpty() && !obj.getName1().isEmpty()) {
        return writer1;
    } else {
        return writer2;
    }
}
}

Eclipse一直告诉我: 类型为ClassifierCompositeItemWriter的setClassifier(Classifier>)不适用于参数(MySpecialClassifier)

Eclipse keeps telling me : setClassifier(Classifier>) in the type ClassifierCompositeItemWriter is not applicable for the arguments (MySpecialClassifier)

推荐答案

您的分类器应如下所示:

You classifier should be like this:

public class MySpecialClassifier implements Classifier<MyObject, ItemWriter<? super MyObject>> {

    @Autowired
    ItemWriter<MyObject> writer1;

    @Autowired
    ItemWriter<MyObject> writer2;

    @Override
    public ItemWriter<MyObject> classify(MyObject obj) {

        if (!obj.getName().isEmpty() && !obj.getName1().isEmpty()) {
            return writer1;
        } else {
            return writer2;
        }
    }

}

唯一的区别是implements Classifier<MyObject, ItemWriter<? super MyObject>>而不是implements Classifier<MyObject, ItemWriter<MyObject>>.

这是因为项目编写者不仅可以写入MyObject项目，而且可以写入MyObject的超类项目.

This is because an item writer can not only write MyObject items but also items of a superclass of MyObject.

这篇关于如何将Classifier与ClassifierCompositeItemWriter结合使用?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！