Joiner
作用：将多个对象拼接成一个字符串示例
Joiner joiner = Joiner.on(";").skipNulls(); return joiner.join(bpeApplication, pipeline, deviceName, field);源码
/** * Returns a joiner which automatically places {@code separator} between consecutive elements. */ public static Joiner on(String separator) { return new Joiner(separator); } /** * Returns a string containing the string representation of each argument, using the previously * configured separator between each. */ public final String join(@Nullable Object first, @Nullable Object second, Object... rest) { return join(iterable(first, second, rest)); } public final String join(Iterable parts) { return join(parts.iterator()); } public final String join(Iterator parts) { return appendTo(new StringBuilder(), parts).toString(); } public final String join(Iterator parts) { return appendTo(new StringBuilder(), parts).toString(); } public A appendTo(A appendable, Iterator parts) throws IOException { checkNotNull(appendable); if (parts.hasNext()) { appendable.append(toString(parts.next())); while (parts.hasNext()) { appendable.append(separator); appendable.append(toString(parts.next())); } } return appendable; }Splitter
Splitter提供Joiner对应的功能。示例
Splitter.on(',').split("foo,bar") 返回：This invocation returns anIterable
containing "foo" and "bar", in that order.
By default Splitter's behavior is very simplistic:
["foo", "", "bar", " quux"]. Notice that the splitter does not assume that you want empty strings removed, or that you wish to trim whitespace. If you want features like these, simply ask for them:private static final Splitter MY_SPLITTER = Splitter.on(',')
.omitEmptyStrings(); Now
MY_SPLITTER.split("foo, ,bar, quux,") returns an iterable containing just ["foo", "bar", "quux"]. Note that the order in which the configuration methods are called is never significant; for instance, trimming is always applied first before checking for an empty result, regardless of the order in which the trimResults() and omitEmptyStrings() methods were invoked.