StringUtils.trimToNull(null)          = null
StringUtils.trimToNull("")            = null
StringUtils.trimToNull("     ")       = null
StringUtils.trimToNull("abc")         = "abc"
StringUtils.trimToNull("    abc    ") = "abc"

        

public static void main(String[] args) {
	System.out.println(StringUtils.trimToNull(null));
	System.out.println(StringUtils.trimToNull(""));
	System.out.println(StringUtils.trimToNull(" "));
	System.out.println(StringUtils.trimToNull(" BTC     "));
}

        

public void testTrimToNull() {
	String FOO = "foo";
	assertEquals(FOO, StringUtils.trimToNull(FOO + "  "));
	assertEquals(FOO, StringUtils.trimToNull(" " + FOO + "  "));
	assertEquals(FOO, StringUtils.trimToNull(" " + FOO));
	assertEquals(FOO, StringUtils.trimToNull(FOO + ""));
	assertEquals(null, StringUtils.trimToNull(" \t\r\n\b "));
	assertEquals(null, StringUtils.trimToNull(StringUtilsTest.TRIMMABLE));
	assertEquals(StringUtilsTest.NON_TRIMMABLE, StringUtils.trimToNull(StringUtilsTest.NON_TRIMMABLE));
	assertEquals(null, StringUtils.trimToNull(""));
	assertEquals(null, StringUtils.trimToNull(null));
}

        

StringUtils.trimToNull(null) = null
StringUtils.trimToNull("") = null
StringUtils.trimToNull(" ") = null
StringUtils.trimToNull(" \b \t \n \f \r ") = null
StringUtils.trimToNull(" \n\tss \b") = "ss"
StringUtils.trimToNull(" d d dd ") = "d d dd"
StringUtils.trimToNull("dd ") = "dd"
StringUtils.trimToNull(" dd ") = "dd"

        

String test1 = "\t";
String test2 = "  A  Test  ";
String test3 = null;

System.out.println( "test1 trimToNull: " + StringUtils.trimToNull( test1 ) );
System.out.println( "test2 trimToNull: " + StringUtils.trimToNull( test2 ) );
System.out.println( "test3 trimToNull: " + StringUtils.trimToNull( test3 ) );

        

private String buildConditions(String prefix, List<String> conditions, List<String> operators) {
	StringBuilder builder = new StringBuilder();
	if (conditions.size()>0) {
		if (StringUtils.trimToNull(prefix)!=null) {
			builder.append(" ").append(prefix).append(" ");
		}
		for (int i=0; i<conditions.size(); i++) {
			String condition = conditions.get(i);
			builder.append(condition).append(" ");
			if (i<conditions.size()-1) {
				String operator = StringUtils.trimToNull(operators.get(i));
				if (operator!=null) {
					builder.append(operator).append(" ");
				}
			}
		}
	}
	return builder.toString();
}

        

public static String getFileKey(String name) {
    String prefix = "/upload/" + DateKit.dateFormat(new Date(), "yyyy/MM");
    if (!new File(AttachController.CLASSPATH + prefix).exists()) {
        new File(AttachController.CLASSPATH + prefix).mkdirs();
    }

    name = StringUtils.trimToNull(name);
    if (name == null) {
        return prefix + "/" + UUID.UU32() + "." + null;
    } else {
        name = name.replace('\\', '/');
        name = name.substring(name.lastIndexOf("/") + 1);
        int index = name.lastIndexOf(".");
        String ext = null;
        if (index >= 0) {
            ext = StringUtils.trimToNull(name.substring(index + 1));
        }
        return prefix + "/" + UUID.UU32() + "." + (ext == null ? null : (ext));
    }
}

        

public String[] deserialize(JsonParser jsonParser, DeserializationContext context) throws IOException {
    final List<String> list = new ArrayList<>();
    final JsonNode node = jsonParser.readValueAsTree();
    if (node.isArray()) {
        final Iterator elements = node.elements();
        while (elements.hasNext()) {
            final JsonNode childNode = (JsonNode) elements.next();
            final String value = StringUtils.trimToNull(childNode.asText());
            if (value != null) {
                list.add(value);
            }
        }
    }
    if (list.size() == 0) {
        return null;
    } else {
        return list.toArray(new String[list.size()]);
    }
}

        

private void parseRecords(InputStream stream) throws IOException {
    LineIterator it = IOUtils.lineIterator(buffer(stream), IabFile.CHARSET);
    while (it.hasNext()) {
        String record = StringUtils.trimToNull(it.nextLine());
        if (record != null) {
            if (isCidrNotation(record)) {
                cidrAddresses.add(subnetInfo(record));
            } else {
                plainAddresses.add(record);
            }
        }
    }
}

        

public void savezhoubao(String content) {
    if (StringUtils.isNotEmpty(content)) {
        content = StringUtils.trimToNull(content);
    }
    redisTemplate.opsForValue().set("zhoubao", content);
}