diff --git a/pom.xml b/pom.xml
index 0a629230..754c945e 100644
--- a/pom.xml
+++ b/pom.xml
@@ -4,7 +4,7 @@
     <modelVersion>4.0.0</modelVersion>
     <groupId>com.alibaba</groupId>
     <artifactId>easyexcel</artifactId>
-    <version>2.0.0-beta6</version>
+    <version>2.0.0</version>
     <packaging>jar</packaging>
     <name>easyexcel</name>
 
@@ -59,12 +59,12 @@
         <dependency>
             <groupId>org.apache.poi</groupId>
             <artifactId>poi</artifactId>
-            <version>4.0.1</version>
+            <version>3.17</version>
         </dependency>
         <dependency>
             <groupId>org.apache.poi</groupId>
             <artifactId>poi-ooxml</artifactId>
-            <version>4.0.1</version>
+            <version>3.17</version>
         </dependency>
         <dependency>
             <groupId>cglib</groupId>
diff --git a/quickstart.md b/quickstart.md
index fccc2a84..2b6323f9 100644
--- a/quickstart.md
+++ b/quickstart.md
@@ -8,7 +8,7 @@
 * 读取图片
 * 宏
 #### 关于版本兼容
-目前poi用的 4.0.1 建议检查是否该版本。如果出现找不到class之类的，八成就是这个原因。
+目前poi用的 4.0.1 建议检查是否该版本。如果看到`NoClassDefFoundError`或者`ClassNotFoundException`，请查看poi相关版本是否都为4.0.1。
 #### 详细参数介绍
 有些参数不知道怎么用，或者有些功能不知道用什么参数，参照：[详细参数介绍](/docs/API.md)
 #### 开源项目不容易，如果觉得本项目对您的工作还是有帮助的话，请在右上角帮忙点个★Star。
diff --git a/src/main/java/com/alibaba/excel/analysis/ExcelAnalyserImpl.java b/src/main/java/com/alibaba/excel/analysis/ExcelAnalyserImpl.java
index 5adc237e..dcae5f1b 100644
--- a/src/main/java/com/alibaba/excel/analysis/ExcelAnalyserImpl.java
+++ b/src/main/java/com/alibaba/excel/analysis/ExcelAnalyserImpl.java
@@ -15,7 +15,6 @@ import com.alibaba.excel.context.AnalysisContext;
 import com.alibaba.excel.context.AnalysisContextImpl;
 import com.alibaba.excel.exception.ExcelAnalysisException;
 import com.alibaba.excel.exception.ExcelAnalysisStopException;
-import com.alibaba.excel.exception.ExcelGenerateException;
 import com.alibaba.excel.read.metadata.ReadSheet;
 import com.alibaba.excel.read.metadata.ReadWorkbook;
 import com.alibaba.excel.read.metadata.holder.ReadWorkbookHolder;
@@ -64,7 +63,8 @@ public class ExcelAnalyserImpl implements ExcelAnalyser {
                 if (poifsFileSystem.getRoot().hasEntry(Decryptor.DEFAULT_POIFS_ENTRY)) {
                     InputStream decryptedStream = null;
                     try {
-                        decryptedStream = DocumentFactoryHelper.getDecryptedStream(poifsFileSystem.getRoot(), null);
+                        decryptedStream =
+                            DocumentFactoryHelper.getDecryptedStream(poifsFileSystem.getRoot().getFileSystem(), null);
                         excelExecutor = new XlsxSaxAnalyser(analysisContext, decryptedStream);
                         return;
                     } finally {
diff --git a/src/main/java/com/alibaba/excel/analysis/v07/handlers/DefaultCellHandler.java b/src/main/java/com/alibaba/excel/analysis/v07/handlers/DefaultCellHandler.java
index 5a52c996..c0ad7064 100644
--- a/src/main/java/com/alibaba/excel/analysis/v07/handlers/DefaultCellHandler.java
+++ b/src/main/java/com/alibaba/excel/analysis/v07/handlers/DefaultCellHandler.java
@@ -8,6 +8,8 @@ import static com.alibaba.excel.constant.ExcelXmlConstants.CELL_VALUE_TAG;
 import static com.alibaba.excel.constant.ExcelXmlConstants.CELL_VALUE_TYPE_TAG;
 
 import java.math.BigDecimal;
+import java.util.Deque;
+import java.util.LinkedList;
 import java.util.Map;
 import java.util.TreeMap;
 
@@ -34,8 +36,7 @@ import com.alibaba.excel.util.StringUtils;
  */
 public class DefaultCellHandler implements XlsxCellHandler, XlsxRowResultHolder {
     private final AnalysisContext analysisContext;
-    private String currentTag;
-    private String currentCellIndex;
+    private Deque<String> currentTagDeque = new LinkedList<String>();
     private int curCol;
     private Map<Integer, CellData> curRowContent = new TreeMap<Integer, CellData>();
     private CellData currentCellData;
@@ -62,11 +63,10 @@ public class DefaultCellHandler implements XlsxCellHandler, XlsxRowResultHolder
 
     @Override
     public void startHandle(String name, Attributes attributes) {
-        currentTag = name;
+        currentTagDeque.push(name);
         // start a cell
         if (CELL_TAG.equals(name)) {
-            currentCellIndex = attributes.getValue(ExcelXmlConstants.POSITION);
-            curCol = PositionUtils.getCol(currentCellIndex);
+            curCol = PositionUtils.getCol(attributes.getValue(ExcelXmlConstants.POSITION));
 
             // t="s" ,it's means String
             // t="str" ,it's means String,but does not need to be read in the 'sharedStrings.xml'
@@ -101,6 +101,7 @@ public class DefaultCellHandler implements XlsxCellHandler, XlsxRowResultHolder
 
     @Override
     public void endHandle(String name) {
+        currentTagDeque.pop();
         if (CELL_VALUE_TAG.equals(name)) {
             // Have to go "sharedStrings.xml" and get it
             if (currentCellData.getType() == CellDataTypeEnum.STRING) {
@@ -134,6 +135,7 @@ public class DefaultCellHandler implements XlsxCellHandler, XlsxRowResultHolder
         if (StringUtils.isEmpty(currentCellValue)) {
             return;
         }
+        String currentTag = currentTagDeque.peek();
         if (currentTag == null) {
             return;
         }
diff --git a/src/main/java/com/alibaba/excel/converters/booleanconverter/BooleanNumberConverter.java b/src/main/java/com/alibaba/excel/converters/booleanconverter/BooleanNumberConverter.java
index 06ac0c73..a0042eaa 100644
--- a/src/main/java/com/alibaba/excel/converters/booleanconverter/BooleanNumberConverter.java
+++ b/src/main/java/com/alibaba/excel/converters/booleanconverter/BooleanNumberConverter.java
@@ -27,7 +27,7 @@ public class BooleanNumberConverter implements Converter<Boolean> {
     @Override
     public Boolean convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
         GlobalConfiguration globalConfiguration) {
-        if (BigDecimal.ONE.equals(cellData.getNumberValue())) {
+        if (BigDecimal.ONE.compareTo(cellData.getNumberValue()) == 0) {
             return Boolean.TRUE;
         }
         return Boolean.FALSE;
diff --git a/src/main/java/com/alibaba/excel/converters/string/StringNumberConverter.java b/src/main/java/com/alibaba/excel/converters/string/StringNumberConverter.java
index 89cbe1d2..f536a088 100644
--- a/src/main/java/com/alibaba/excel/converters/string/StringNumberConverter.java
+++ b/src/main/java/com/alibaba/excel/converters/string/StringNumberConverter.java
@@ -2,7 +2,6 @@ package com.alibaba.excel.converters.string;
 
 import java.math.BigDecimal;
 
-import org.apache.poi.hssf.usermodel.HSSFDateUtil;
 import org.apache.poi.ss.usermodel.DateUtil;
 
 import com.alibaba.excel.converters.Converter;
diff --git a/src/main/java/com/alibaba/excel/support/ExcelTypeEnum.java b/src/main/java/com/alibaba/excel/support/ExcelTypeEnum.java
index a267e1de..2f02327c 100644
--- a/src/main/java/com/alibaba/excel/support/ExcelTypeEnum.java
+++ b/src/main/java/com/alibaba/excel/support/ExcelTypeEnum.java
@@ -1,6 +1,8 @@
 package com.alibaba.excel.support;
 
+import java.io.BufferedInputStream;
 import java.io.File;
+import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 
@@ -31,7 +33,12 @@ public enum ExcelTypeEnum {
         try {
             FileMagic fileMagic;
             if (file != null) {
-                fileMagic = FileMagic.valueOf(file);
+                BufferedInputStream bufferedInputStream = new BufferedInputStream(new FileInputStream(file));
+                try {
+                    fileMagic = FileMagic.valueOf(bufferedInputStream);
+                } finally {
+                    bufferedInputStream.close();
+                }
                 if (!FileMagic.OLE2.equals(fileMagic) && !FileMagic.OOXML.equals(fileMagic)) {
                     String fileName = file.getName();
                     if (fileName.endsWith(XLSX.getValue())) {
diff --git a/src/main/java/com/alibaba/excel/write/style/column/LongestMatchColumnWidthStyleStrategy.java b/src/main/java/com/alibaba/excel/write/style/column/LongestMatchColumnWidthStyleStrategy.java
index 320573bd..fb807f39 100644
--- a/src/main/java/com/alibaba/excel/write/style/column/LongestMatchColumnWidthStyleStrategy.java
+++ b/src/main/java/com/alibaba/excel/write/style/column/LongestMatchColumnWidthStyleStrategy.java
@@ -21,7 +21,7 @@ public class LongestMatchColumnWidthStyleStrategy extends AbstractColumnWidthSty
 
     private static final int MAX_COLUMN_WIDTH = 256;
 
-    Map<Integer, Map<Integer, Integer>> cache = new HashMap<Integer, Map<Integer, Integer>>(8);
+    private static final Map<Integer, Map<Integer, Integer>> CACHE = new HashMap<Integer, Map<Integer, Integer>>(8);
 
     @Override
     protected void setColumnWidth(WriteSheetHolder writeSheetHolder, CellData cellData, Cell cell, Head head,
@@ -29,10 +29,10 @@ public class LongestMatchColumnWidthStyleStrategy extends AbstractColumnWidthSty
         if (!isHead && cellData == null) {
             return;
         }
-        Map<Integer, Integer> maxColumnWidthMap = cache.get(writeSheetHolder.getSheetNo());
+        Map<Integer, Integer> maxColumnWidthMap = CACHE.get(writeSheetHolder.getSheetNo());
         if (maxColumnWidthMap == null) {
             maxColumnWidthMap = new HashMap<Integer, Integer>(16);
-            cache.put(writeSheetHolder.getSheetNo(), maxColumnWidthMap);
+            CACHE.put(writeSheetHolder.getSheetNo(), maxColumnWidthMap);
         }
         Integer columnWidth = dataLength(cellData, cell, isHead);
         if (columnWidth < 0) {
diff --git a/src/test/java/com/alibaba/easyexcel/test/core/converter/ReadAllConverterDataListener.java b/src/test/java/com/alibaba/easyexcel/test/core/converter/ReadAllConverterDataListener.java
index f4f0a1e7..c8b5d8bf 100644
--- a/src/test/java/com/alibaba/easyexcel/test/core/converter/ReadAllConverterDataListener.java
+++ b/src/test/java/com/alibaba/easyexcel/test/core/converter/ReadAllConverterDataListener.java
@@ -65,7 +65,8 @@ public class ReadAllConverterDataListener extends AnalysisEventListener<ReadAllC
         Assert.assertEquals(data.getStringString(), "测试");
         Assert.assertEquals(data.getStringError(), "#VALUE!");
         Assert.assertEquals(data.getStringNumberDate(), "2020-01-01 01:01:01");
-        Assert.assertEquals(data.getStringFormulaNumber(), "2.0");
+        double doubleStringFormulaNumber = new BigDecimal(data.getStringFormulaNumber()).doubleValue();
+        Assert.assertEquals(doubleStringFormulaNumber, 2.0, 0.0);
         Assert.assertEquals(data.getStringFormulaString(), "1测试");
         LOGGER.debug("First row:{}", JSON.toJSONString(list.get(0)));
     }
diff --git a/src/test/java/com/alibaba/easyexcel/test/temp/simple/HgTest.java b/src/test/java/com/alibaba/easyexcel/test/temp/simple/HgTest.java
index e0032fd0..1f1db7be 100644
--- a/src/test/java/com/alibaba/easyexcel/test/temp/simple/HgTest.java
+++ b/src/test/java/com/alibaba/easyexcel/test/temp/simple/HgTest.java
@@ -24,7 +24,7 @@ public class HgTest {
     @Test
     public void hh() throws IOException {
         List<Object> list =
-            EasyExcel.read(new FileInputStream("D:\\test\\test.xlsx")).headRowNumber(0).sheet().doReadSync();
+            EasyExcel.read(new FileInputStream("D:\\test\\折扣2007.xls")).headRowNumber(0).sheet().doReadSync();
         for (Object data : list) {
             LOGGER.info("返回数据：{}", JSON.toJSONString(data));
         }
diff --git a/update.md b/update.md
index 60dd1edf..0efb5ef5 100644
--- a/update.md
+++ b/update.md
@@ -1,3 +1,8 @@
+# 2.0.0
+* 修复当cell为空可能会抛出空指针的bug
+* 修复电话等长数字可能出现科学计数法的问题 [Issue #583](https://github.com/alibaba/easyexcel/issues/583)
+* 升级为正式版
+
 # 2.0.0-beta6
 * 修复空行读取空指针异常
 * 修复写入指定头为List<List<String>>,但是数据用List<Class>导致的空指针