java-classic-code/java-excel/OnceReadListener.java

package cn.exlive.exbooter.excel;

import com.alibaba.excel.context.AnalysisContext;
import com.alibaba.excel.event.AnalysisEventListener;
import com.google.common.collect.Lists;
import com.google.common.collect.Sets;
import org.apache.commons.lang3.StringUtils;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.stream.Collectors;

/**
 * Excel 读取数据，滑动读取表头，读取到表头后，开始读取数据。如果没有读取到表头，就没有数据。
 *
 * <pre>
 *
 * Created by zhenqin.
 * User: zhenqin
 * Date: 2022/10/6
 * Time: 下午5:44
 * Vendor: yiidata.com
 *
 * </pre>
 *
 * @author zhenqin
 */
public class OnceReadListener extends AnalysisEventListener<Object> {

    /**
     * 预期的标题 Header
     */
    final Map<String, String> headerFieldMapping;

    /**
     * 实际数据
     */
    private List<Object> list = new ArrayList<Object>();

    /**
     * 实际的 Header
     */
    Map<Integer, String> headMap;

    /**
     * 是否有 header
     */
    volatile boolean hasHeader;

    public OnceReadListener(Map<String, String> headerFieldMapping) {
        this.headerFieldMapping = headerFieldMapping;
    }

    /**
     * 滑动读取表头
     * @param headMap Excel 实际表头
     * @param context
     */
    @Override
    public void invokeHeadMap(Map<Integer, String> headMap, AnalysisContext context) {
        Map<Integer, String> newHeadMap = new HashMap<>(headMap.size());
        // 使用 Stream API 对换 Key 和 Value
        Map<String, Integer> headMapInverse = new HashMap<>(headMap.size());
        for (Map.Entry<Integer, String> entry : headMap.entrySet()) {
            final String oriHead = entry.getValue();
            headMapInverse.put(oriHead, entry.getKey());

            String head = oriHead;
            // head 可能包含特殊字符
            if(head.contains("*")) {
                head = head.replaceAll("\\*", "");
            } else if(head.contains("(")) {
                head = head.startsWith("(") ? head.substring(head.indexOf(")") + 1) : head.substring(0, head.indexOf("("));
            } else if(head.contains("（")) {
                head = head.startsWith("（") ? head.substring(head.indexOf("）") + 1) : head.substring(0, head.indexOf("（"));
            } else if(head.contains("【")) {
                head = head.startsWith("【") ? head.substring(head.indexOf("】") + 1) : head.substring(0, head.indexOf("【"));
            } else if(head.contains("[")) {
                head = head.startsWith("[") ? head.substring(head.indexOf("]") + 1) : head.substring(0, head.indexOf("["));
            }
            // oriHead 中 包含特殊字符
            if(!StringUtils.equals(oriHead, head)) {
                headMapInverse.put(head, entry.getKey());
            }
        }
        int matchCount = 0;
        final HashSet<Map.Entry<String, String>> entries = new HashSet<>(headerFieldMapping.entrySet());
        for (Map.Entry<String, String> entry : entries) {
            String key = entry.getKey();
            if(key.contains("*")) {
                key = key.replaceAll("\\*", "");
            } else if(key.contains("(")) {
                key = key.startsWith("(") ? key.substring(key.indexOf(")") + 1) : key.substring(0, key.indexOf("("));
            } else if(key.contains("（")) {
                key = key.startsWith("（") ? key.substring(key.indexOf("）") + 1) : key.substring(0, key.indexOf("（"));
            } else if(key.contains("【")) {
                key = key.startsWith("【") ? key.substring(key.indexOf("】") + 1) : key.substring(0, key.indexOf("【"));
            } else if(key.contains("[")) {
                key = key.startsWith("[") ? key.substring(key.indexOf("]") + 1) : key.substring(0, key.indexOf("["));
            }
            final Integer index = headMapInverse.get(key);
            if(index != null) {
                matchCount++;
                newHeadMap.put(index, key);
            }
            // 检测是否发生了变化，如果变化，则重新放入
            if(!StringUtils.equals(entry.getKey(), key)) {
                // 重新放入新的字段
                headerFieldMapping.put(key, entry.getValue());
            }
        }

        // 如果 10个 header，满足了 6 个，则成功
        if((matchCount * 1.0f / headerFieldMapping.size()) >= 0.5f) {
            this.headMap = newHeadMap;
            this.hasHeader = true;
        }
    }

    /**
     * 处理数据，需要判断 header 是否读取到，读取不到则往下继续读，直到结束
     * @param object    one row value. It is same as {@link AnalysisContext#readRowHolder()}
     * @param context analysis context
     */
    @Override
    public void invoke(Object object, AnalysisContext context) {
        // 先找到表头，有时候表头不在第一行
        if(!hasHeader) {
            this.invokeHeadMap((Map<Integer, String>)object, context);
            return;
        }
        //System.out.println(object);
        list.add(object);
    }

    @Override
    public void doAfterAllAnalysed(AnalysisContext context) {

    }

    /**
     * 返回表头，如果没有读取到表头，则返回 null
     * @return
     */
    public Map<Integer, String> getHeadMap() {
        return headMap;
    }

    @Override
    public boolean hasNext(AnalysisContext context) {
        return super.hasNext(context);
    }

    /**
     * 返回数据列表
     * @return
     */
    public List<Object> getList() {
        return list;
    }

    public void setList(List<Object> list) {
        this.list = list;
    }
}