使用JXL生成Excel时发生java.lang.ArrayIndexOutOfBoundsException错误

错误信息如下：

......

java.lang.ArrayIndexOutOfBoundsException
        at java.lang.System.arraycopy(Native Method)
        at jxl.biff.StringHelper.getBytes(StringHelper.java:127)
        at jxl.write.biff.WriteAccessRecord.<init>(WriteAccessRecord.java:59)
        at jxl.write.biff.WritableWorkbookImpl.write(WritableWorkbookImpl.java:726) 

......

根据错误信息的提示，发现问题出在WriteAccessRecord文件里，其源代码如下所示：

package jxl.write.biff;  
  
import jxl.Workbook;  
import jxl.biff.StringHelper;  
import jxl.biff.Type;  
import jxl.biff.WritableRecordData;  
  
/** 
 * The name used when Excel was installed.   
 * When writing worksheets, it uses the value from the WorkbookSettings object, 
 * if this is not set (null) this is hard coded as 
 * Java Excel API + Version number 
 */  
class WriteAccessRecord extends WritableRecordData  
{  
  /** 
   * The data to output to file 
   */  
  private byte[] data;  
  
  // String of length 112 characters  
  /** 
   * The author of this workbook (ie. the Java Excel API) 
   */  
  private final static String authorString = "Java Excel API";  
  private String userName;  
  
  /** 
   * Constructor 
   */  
  public WriteAccessRecord(String userName)  
  {  
    super(Type.WRITEACCESS);  
  
    data = new byte[112];  
    String astring = userName != null ?  
        userName :  
        authorString + " v" + Workbook.getVersion();  
  
    StringHelper.getBytes(astring, data, 0);  
  
    // Pad out the record with space characters  
    for (int i = astring.length() ; i < data.length ;i++)  
    {  
      data[i] = 0x20;  
    }  
  }  
  
  /** 
   * Gets the data for output to file 
   *  
   * @return the binary data 
   */  
  public byte[] getData()  
  {  
    return data;  
  }  
}  

分析上诉代码发现，byte数组data的最大长度被定义为112，当被传入的参数userName达到一定长度时就会抛错。

跟踪代码WritableWorkbookImpl发现，userName实际就是WorkbookSettings类中的writeAccess字段，亦即生成Excel是的用户信息。可能在linux环境UTF8下每个汉字的字节数为3位(Windows中是2位)的缘故，出现了上诉的奇异现象。

 

解决的办法如下：

1.修改JXL源代码中WriteAccessRecord文件代码，重新设置变量data的长度，例如：data = new byte[astring.getBytes().length];