从代码点数字的 IntStream 中创建一个字符串？

Question

如果我正在使用 Java 流，并以 IntStream of code point numbers for Unicode characters, how can I render a CharSequence 结束，例如 String？

String output = "input_goes_here".codePoints(). ??? ;

我在几个接口和类上发现了一个 codePoints() 方法，它们都生成 IntStream 个代码点。然而我还没有找到任何接受相同的构造函数或工厂方法。

我正在寻找相反的：

➥ 如何从 IntStream 个代码点实例化 String 或 CharSequence 等？

Answer 1

使用IntStream::collect with a StringBuilder。

String output = 
    "input_goes_here"
    .codePoints()                            // Generates an `IntStream` of Unicode code points, one `Integer` for each character in the string.
    .collect(                                // Collect the results of processing each code point.
        StringBuilder::new,                  // Supplier<R> supplier
        StringBuilder::appendCodePoint,      // ObjIntConsumer<R> accumulator
        StringBuilder::append                // BiConsumer<R,R> combiner
    )                                        
    .toString()
;

如果你喜欢更笼统的CharSequence interface over concrete String, simply drop the toString() at the end. The returned StringBuilder是CharSequence.

IntStream codePointStream = "input_goes_here".codePoints ();
CharSequence output = codePointStream.collect ( StringBuilder :: new , StringBuilder :: appendCodePoint , StringBuilder :: append );

Answer 2

或更直接到 String 通过使用数组传递给 new String(…)

IntStream intStream = "input_goes_here".codePoints();

int[] arr;
String output = new String( (arr = intStream.toArray()), 0, arr.length );

这是原始的简短解决方案，没有多余的 IntStream intStream 作业：

int[] arr;
String output = new String( (arr = "input_goes_here".codePoints().toArray()), 0, arr.length );

Answer 3

不要忘记 Java IO 库：
使用 IntStream::collect 与 StringWriter

String output = 
    "input_goes_here".codePoints() // Generates an IntStream of Unicode code points,
                                   //  one Integer for each character in the string.
    .collect(                      // Collect the results of processing each code point.
        StringWriter::new,         // Supplier<R> supplier
        StringWriter::write,       // ObjIntConsumer<R> accumulator
        (w1, w2) -> w1.write(      // BiConsumer<R,R> combiner
            w2.toString() ) )
    .toString();

从代码点数字的 IntStream 中创建一个字符串？

Make a string from an IntStream of code point numbers?

java

string

char

java-stream

charsequence