ExportHandleProvider接口

接口作用

希望在导出操作之前，加入一些自定义操作，可以用这个接口实现。比如导出的文件进行自定义加密。

接口内容

主要接口

ExportHandleProvider

package com.finebi.stable.fun;

import com.fr.stable.fun.mark.Mutable;

import java.io.OutputStream;

/**
 * Created by Hiram on 2018/11/14.
 */
public interface ExportHandleProvider extends Mutable {
    String XML_TAG = "ExportHandleProvider";

    int CURRENT_LEVEL = 1;

    /**
     *
     * @param originalOutputStream  原始导出流
     * @param type  导出类型
     * @return 处理后的流
     */
    OutputStream handleStream(OutputStream originalOutputStream, ExportType type);
}

接口接入

<extra-core>
    <ExportHandleProvider class="com.fr.plugin.demo.export.CountExportHandle"/>
</extra-core>

示例效果

简单的统计一下导出文件的大小，输出在日志里面。

写一个拦截处理的CountExportHandle，返回一个CountOutputStream，在write时计数，最后在close的时候输出大小。

示例源码

CountExportHandle

import com.finebi.stable.fun.ExportType;
import com.finebi.stable.fun.impl.AbstractExportHandleProvider;
import java.io.OutputStream;
public class CountExportHandle extends AbstractExportHandleProvider {
    @Override
    public OutputStream handleStream(OutputStream originalOutputStream, ExportType type) {
        return new CountOutputStream(originalOutputStream);
    }

}

CountOutputStream

import com.fr.log.FineLoggerFactory;
import java.io.IOException;
import java.io.OutputStream;


public class CountOutputStream extends OutputStream {

    private OutputStream out;

    private int count;

    public CountOutputStream(OutputStream out) {
        this.out = out;
    }

    @Override
    public void write(int b) throws IOException {
        count++;
        out.write(b);
    }

    @Override
    public void write(byte[] b) throws IOException {
        count += b.length;
        out.write(b);
    }

    @Override
    public void write(byte[] b, int off, int len) throws IOException {
        count += len;
        out.write(b, off, len);
    }

    @Override
    public void flush() throws IOException {
        out.flush();
    }

    @Override
    public void close() throws IOException {
        FineLoggerFactory.getLogger().info("===== export length: {}  ======", count);
        out.close();
    }
}

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