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。