easyexcel验证表头是否一致，并做异常处理停止向下继续解析

使用easyexcel，很多时候客户上传的Excel并没有按照你要求的模板进行上传，所以我们需要去限制上传的Excel模板是否与我们要求的模板一致，验证表头是否一致。

@Override
public void invokeHeadMap(Map<Integer, String> headMap, AnalysisContext context) {
    log.info("解析到一条头数据:{}", JsonUtils.obj2json(headMap));
    if (context.readRowHolder().getRowIndex() == 0) {
        String[] headList = {"序号", "姓名", "性别", "年龄", "文化程度", "民族", "身份证号", "工作单位/学校", "手机/电话", "备注"};
        for (int i = 0; i < headList.length; i++) {
            try {
                if (!headMap.get(i).equals(headList[i])) {
                    isNull = "上传模板与系统模板不匹配，请使用平台模板上传数据";
                    break;
                }
            } catch (Exception e) {
                isNull = "上传模板与系统模板不匹配，请使用平台模板上传数据";
                break;
            }
        }
    }
}

这时候其实模板已经不一样了，也没有必要向下继续校验数据的正确性了，所以需要停止解析了，而尝试了return之类的方法，并没有什么效果，网上搜索了半天，基本都是throw new ExcelAnalysisStopException()做异常

@Override
public void invokeHeadMap(Map<Integer, String> headMap, AnalysisContext context) {
    log.info("解析到一条头数据:{}", JsonUtils.obj2json(headMap));
    if (context.readRowHolder().getRowIndex() == 0) {
        String[] headList = {"序号", "姓名", "性别", "年龄", "文化程度", "民族", "身份证号", "工作单位/学校", "手机/电话", "备注"};
        for (int i = 0; i < headList.length; i++) {
            try {
                if (!headMap.get(i).equals(headList[i])) {
                    isNull = "上传模板与系统模板不匹配，请使用平台模板上传数据";
                    break;
                }
            } catch (Exception e) {
                isNull = "上传模板与系统模板不匹配，请使用平台模板上传数据";
                break;
            }
        }
    }
    throw new ExcelAnalysisException(isNull);
}

/**
 * 在转换异常 获取其他异常下会调用本接口。抛出异常则停止读取。如果这里不抛出异常则 继续读取下一行。
 */
@Override
public void onException(Exception exception, AnalysisContext context) {
    log.error("解析失败，但是继续解析下一行:{}", exception.getMessage());
    // 如果要获取头的信息 配合invokeHeadMap使用
    ExcelDataConvertException excelDataConvertException = null;
    if (exception instanceof ExcelDataConvertException) {
        excelDataConvertException = (ExcelDataConvertException) exception;
        log.error("第{}行，第{}列,{}解析异常", excelDataConvertException.getRowIndex(),
                excelDataConvertException.getColumnIndex(), excelDataConvertException.getCellData());
    }
    if (null != excelDataConvertException) {
        int row = excelDataConvertException.getRowIndex() + 1;
        int col = excelDataConvertException.getColumnIndex() + 1;
        isNull = "第" + row + "行，第" + col + "列，" + excelDataConvertException.getCellData() + "解析异常";
    }
    throw new ExcelAnalysisStopException(isNull);
}

使用这样的异常处理，解析虽然是暂停了，但抛出了异常信息并不是我想要的

09:46:49.188 [main] DEBUG com.alibaba.excel.context.AnalysisContextImpl - Began to read：ReadSheetHolder{sheetNo=0, sheetName='在职员工'} com.alibaba.excel.read.metadata.holder.ReadSheetHolder@7486b455
09:46:50.119 [main] INFO cn.oick.api.ExcelReadIsNullListener - 解析到一条头数据:{"0":"序号","1":"姓名","2":"性别","3":"年龄","4":"工作单位/学校/社区","5":"联系电话","6":"备注"}
09:46:50.120 [main] ERROR cn.oick.api.ExcelReadIsNullListener - 解析失败，但是继续解析下一行:上传模板与系统模板不匹配，请使用平台模板上传数据
Exception in thread "main" com.alibaba.excel.exception.ExcelAnalysisException: 上传模板与系统模板不匹配，请使用平台模板上传数据
	at com.alibaba.excel.read.metadata.holder.AbstractReadHolder.notifyEndOneRow(AbstractReadHolder.java:170)
	at com.alibaba.excel.analysis.v07.handlers.ProcessResultCellHandler.endHandle(ProcessResultCellHandler.java:44)
	at com.alibaba.excel.analysis.v07.XlsxRowHandler.endElement(XlsxRowHandler.java:44)
	at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.endElement(AbstractSAXParser.java:609)
	at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanEndElement(XMLDocumentFragmentScannerImpl.java:1782)
	at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2967)
	at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:602)
	at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:505)
	at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:842)
	at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:771)

然后看到这篇文章《easyexcel 异常处理》同样使用throw new ExcelAnalysisStopException("解析出错："+row+"行 "+column+"列，停止运行");但最后的异常信息是这样的

10:35:50.577 [main] INFO com.example.demo.listener.CustomListener3 - 解析出错：Converter not found, convert STRING to java.time.LocalDateTime
10:35:50.577 [main] ERROR com.example.demo.listener.CustomListener3 - 解析出错：1行 1列
10:35:50.577 [main] DEBUG com.alibaba.excel.analysis.ExcelAnalyserImpl - Custom stop!

这样才是想要的信息，结果看了半天这文章，和之前的并没有什么差别，然后就看到这个类com.alibaba.excel.analysis.ExcelAnalyserImpl

@Override
public void analysis(List readSheetList, Boolean readAll) {
    try {
        if (!readAll && CollectionUtils.isEmpty(readSheetList)) {
            throw new IllegalArgumentException("Specify at least one read sheet.");
        }
        try {
            excelReadExecutor.execute(readSheetList, readAll);
        } catch (ExcelAnalysisStopException e) {
            if (LOGGER.isDebugEnabled()) {
                LOGGER.debug("Custom stop!");
            }
        }
        // The last sheet is read
        if (excelReadExecutor instanceof XlsSaxAnalyser) {
            if (analysisContext.readSheetHolder() != null) {
                analysisContext.readSheetHolder().notifyAfterAllAnalysed(analysisContext);
            }
        }
    } catch (RuntimeException e) {
        finish();
        throw e;
    } catch (Throwable e) {
        finish();
        throw new ExcelAnalysisException(e);
    }
}

通过debug发现，之前抛出的异常并没有走LOGGER.debug("Custom stop!");中，而是走了RuntimeException e，通过另一个类AbstractReadHolder的notifyEndOneRow中发现，我们之前在onException抛出的异常再解析过程中变成了throw new ExcelAnalysisException(exception.getMessage(), exception);

for (ReadListener readListener : analysisContext.currentReadHolder().readListenerList()) {
    try {
        readListener.invoke(readRowHolder.getCurrentRowAnalysisResult(), analysisContext);
    } catch (Exception e) {
        for (ReadListener readListenerException : analysisContext.currentReadHolder().readListenerList()) {
            try {
                readListenerException.onException(e, analysisContext);
            } catch (Exception exception) {
                throw new ExcelAnalysisException(exception.getMessage(), exception);
            }
        }
        break;
    }
    if (!readListener.hasNext(analysisContext)) {
        throw new ExcelAnalysisStopException();
    }
}

异常抛出不行，我们可以使用readListener.hasNext()方法让它抛出throw new ExcelAnalysisStopException();所以我们只需要在之前的监听类中添加这个方法就行了，完整代码如下：

import com.alibaba.excel.context.AnalysisContext;
import com.alibaba.excel.event.AnalysisEventListener;
import com.alibaba.excel.exception.ExcelDataConvertException;
import cn.oick.api.base.util.JsonUtils;
import cn.oick.api.excel.dto.train.ExcelTrainPopularAmbulanceData;
import lombok.extern.slf4j.Slf4j;
import org.springframework.util.StringUtils;

import java.util.Map;

@Slf4j
public class ExcelReadIsNullListener extends AnalysisEventListener {
    // Excel行数
    private int num;
    // 校验规则信息
    private String isNull;
    // 返回的校验规则信息
    public String getIsNull() {
        return isNull;
    }

    /**
     * 如果使用了spring,请使用这个构造方法。每次创建Listener的时候需要把spring管理的类传进来
     */
    public ExcelReadIsNullListener() {
        // 有个很重要的点 DemoDataListener 不能被spring管理，要每次读取excel都要new,然后里面用到spring可以构造方法传进去
        num = 0;
        isNull = "true";
    }

    @Override
    public void invokeHeadMap(Map<Integer, String> headMap, AnalysisContext context) {
        log.info("解析到一条头数据:{}", JsonUtils.obj2json(headMap));
        if (context.readRowHolder().getRowIndex() == 0) {
            String[] headList = {"序号", "姓名", "性别", "年龄", "文化程度", "民族", "身份证号", "工作单位/学校", "手机/电话", "备注"};
            for (int i = 0; i < headList.length; i++) {
                try {
                    if (!headMap.get(i).equals(headList[i])) {
                        isNull = "上传模板与系统模板不匹配，请使用平台模板上传数据";
                        break;
                    }
                } catch (Exception e) {
                    isNull = "上传模板与系统模板不匹配，请使用平台模板上传数据";
                    break;
                }
            }
        }
    }

    /**
     * 在转换异常 获取其他异常下会调用本接口。抛出异常则停止读取。如果这里不抛出异常则 继续读取下一行。
     */
    @Override
    public void onException(Exception exception, AnalysisContext context) {
        log.error("解析失败，但是继续解析下一行:{}", exception.getMessage());
        // 如果要获取头的信息 配合invokeHeadMap使用
        ExcelDataConvertException excelDataConvertException = null;
        if (exception instanceof ExcelDataConvertException) {
            excelDataConvertException = (ExcelDataConvertException) exception;
            log.error("第{}行，第{}列,{}解析异常", excelDataConvertException.getRowIndex(),
                    excelDataConvertException.getColumnIndex(), excelDataConvertException.getCellData());
        }
        if (null != excelDataConvertException) {
            int row = excelDataConvertException.getRowIndex() + 1;
            int col = excelDataConvertException.getColumnIndex() + 1;
            isNull = "第" + row + "行，第" + col + "列，" + excelDataConvertException.getCellData() + "解析异常";
        }
    }

    /**
     * 这个每一条数据解析都会来调用
     */
    @Override
    public void invoke(ExcelTrainPopularAmbulanceData data, AnalysisContext context) {
        log.info("解析到一条数据:{}", JsonUtils.obj2json(data));
        int row = context.readRowHolder().getRowIndex() + 1;
        if (StringUtils.isEmpty(data.getName())) {
            isNull = "第" + row + "行，第" + 2 + "列，" + "姓名不能为空";
        }
        num++;
    }

    /**
     * 当出现模板数据异常时，结束往下解析，抛出异常
     */
    @Override
    public boolean hasNext(AnalysisContext context) {
        return "true".equals(isNull);
    }

    /**
     * 所有数据解析完成了 都会来调用
     */
    @Override
    public void doAfterAllAnalysed(AnalysisContext context) {
        log.info("所有数据校验完成！");
        if (num == 0 && "true".equals(isNull)) {
            isNull = "请勿上传空数据文件";
        }
    }
}

输出了我想要的校验信息

10:27:47.821 [main] DEBUG com.alibaba.excel.context.AnalysisContextImpl - Began to read：ReadSheetHolder{sheetNo=0, sheetName='在职员工'} com.alibaba.excel.read.metadata.holder.ReadSheetHolder@7486b455
10:27:48.417 [main] INFO cn.oick.api.ExcelReadIsNullListener - 解析到一条头数据:{"0":"序号","1":"姓名","2":"性别","3":"年龄","4":"工作单位/学校/社区","5":"联系电话","6":"备注"}
10:27:48.418 [main] DEBUG com.alibaba.excel.analysis.ExcelAnalyserImpl - Custom stop!
10:27:48.420 [main] INFO cn.oick.api.WxhhApplicationTests - 规则校验：上传模板与系统模板不匹配，请使用平台模板上传数据