Oracle数据库中CLOB字段的比较，使用Java代码。

最近需要比较两个CLOB字段的内容是否相同，得用Java代码实现。 实验了几种方案之后，觉得下面这个比较好一些。

 

过程如下：

 

 private boolean isEqualCLOB(CLOB sourceCLOB, CLOB targetCLOB) {
  
  boolean retVal = true;
  
  try {
   if ((null != sourceCLOB) && (null != targetCLOB)) {
    // both not null, should compare.
    
    if (sourceCLOB.length() != targetCLOB.length()) {
     // length diff, diff.
     retVal = false;
    } else {
     // length same, should compare the content.
     InputStream inStreamSource = sourceCLOB.getAsciiStream();
     InputStream inStreamTarget = targetCLOB.getAsciiStream();
     
     retVal = cmpTwoStreams(inStreamSource, inStreamTarget);
     
     inStreamSource.close();
     inStreamTarget.close();
    } // end compare the length.
    
   } else if ((null == sourceCLOB) && (null == targetCLOB)) {
    // both null, equal.
    retVal = true;
   } else {
    // only one is null. diff.
    retVal = false;
   }
   
  } catch (Exception e) {
   // do as you like.
   ;
  }
  
  return retVal;
 }
 
 private boolean cmpTwoStreams(InputStream streamSource, InputStream streamTarget) throws IOException {
  
  boolean retVal = true;
  
  byte s = (byte)0;
  byte t = (byte)0;
  
  // As we compare the streams only the two CLOB has same length.
  while(( s = (byte)streamSource.read()) != -1) {
   
   t = (byte)streamTarget.read();
   if (s != t) {
    retVal = false;
    break;
   }
  
  } // end loop of source stream.
  
  return retVal;
 }

 

以上代码，已经测试。

 

 

如果有其他好的思路，希望可以交流一下。目的是快速而且占用空间少。