e969. retrieving all the text from a jtextcomponent efficiently.txt

来自「这里面包含了一百多个JAVA源文件」· 文本 代码 · 共 37 行

The text contained in a text component is not always stored contiguously. Therefore, retrieving text using getText() may cause a new String object to be created and the text copied to the new string. If you do not need the text in one contiguous chunk, the most efficient way to retrieve the text is in pieces called segments. This example retrieves the entire contents of a text component in segments. 
    // Create the text component
    JTextComponent textComp = new JTextPane();
    Document doc = textComp.getDocument();
    
    // Create a segment to hold the characters in the document
    Segment segment = new Segment();
    int pos = 0;
    segment.setPartialReturn(true);
    
    try {
        // Retrieve all segments
        while (pos < doc.getLength()) {
            // Ask for the remainder of the document text
            doc.getText(pos, doc.getLength()-pos, segment);
    
            // You can access the contents directly from the array in the segment.
            // Never modify the contents of the array
            for (int i=0; i<segment.count; i++) {
                int positionInDoc = pos+i;
                char charAtPos = segment.array[i+segment.offset];
            }
    
            // Or use the segment as a character iterator
            int i=0;
            for(char c=segment.first(); c != CharacterIterator.DONE; c=segment.next(), i++) {
                int positionInDoc = pos+i;
                char charAtPos = c;
            }
    
            // Increment pos by the actual number of characters retrieved
            pos += segment.count;
        }
    } catch (BadLocationException e) {
    }