您可以使用任何 JTextComponent 并通过一些方法（如下提供）您可以从文本中收集几个不同的项目，例如：
- 位于当前鼠标指针位置下的字符；
- 位于当前鼠标指针位置下的Word；
- 位于当前鼠标指针位置下的选定文本
（如果选择）；
- 位于当前鼠标指针位置下的突出显示文本
（如果您也想在文本中突出显示）；
- 鼠标指针下的文本是否被选中？;
- 鼠标指针下的文本是否突出显示？
正如@camickr 已经如此慷慨地指出的那样，这里的关键是使用 JTextComponent.viewToModel() 方法（我相信所有 Swing Text 组件都包含该方法）以获取与当前鼠标指针在组件内的位置相关的文本索引位置。
这里有一些方法可以玩：
/**
* This method will return either boolean true or false if the text contained
* under the current mouse pointer location within a JTextComponent is Selected
* or not. If the text under the mouse is found to be Selected then boolean
* true is returned. If the text under the mouse pointer is NOT found to be
* Selected then boolean false is returned.<br><br>
*
* This method is not to be confused with the getHighlightedUnderMouse() method.
* Highlighted text and Selected text are two completely different things.
* Highlighted Text can be text which is Highlighted (generally with a specific
* color) and can be in many different locations throughout the entire document
* whereas Selected Text is generally done by dragging the mouse over a document
* location while holding the left mouse button making the text SELECTED.<br><br>
*
* This method is generally run within a JTextComponent MouseMove Event but can be
* run from any JTextComponent Mouse event which will provide the current mouse
* coordinates within the supplied JTextComponent Object.
*
* @param textComp (JTextComponent) The JTextComponent object to work on. This
* can be the component variable name for either a JTextField, JTextArea,
* JFormattedField, JPasswordField, JTextPane, and JEditorPane.<br>
*
* @param textAreaMouseXLocation (Integer) The current X Location of the mouse
* pointer. This value can be acquired from the JTextComponent's MouseMove event like
* this <code>int x = evt.getX();</code> where evt is the <b>java.awt.event.MouseEvent</b>
* parameter variable.<br>
*
* @param textAreaMouseYLocation (Integer) The current Y Location of the mouse
* pointer. This value can be acquired from the JTextComponent's MouseMove event like
* this <code>int y = evt.getY();</code> where evt is the <b>java.awt.event.MouseEvent</b>
* parameter variable.<br>
*
* @return (Boolean) True if the text under the current mouse pointer location
* within the supplied JTextComponent is Selected and false if it is not.
*/
public static boolean isSelectededUnderMouse(JTextComponent textComp, int textAreaMouseXLocation,
int textAreaMouseYLocation) {
boolean isSelected = false;
if (textComp.getText().isEmpty()) { return false; }
Point pt = new Point(textAreaMouseXLocation, textAreaMouseYLocation);
int pos = textComp.viewToModel(pt);
int start = textComp.getSelectionStart();
int end = textComp.getSelectionEnd();
if (pos >= start && pos <= end) {
isSelected = true;
}
return isSelected;
}
/**
* This method will return either boolean true or false if the text contained
* under the current mouse pointer location within a JTextComponent is Highlighted
* or not. If the text under the mouse is found to be Highlighted then boolean
* true is returned. If the text under the mouse pointer is not found to be
* highlighted then boolean false is returned.<br><br>
*
* This method is not to be confused with the getSelectedUnderMouse() method.
* Highlighted text and Selected text are two completely different things.
* Highlighted Text can be text which is Highlighted (generally with a specific
* color) and can be in many different locations throughout the entire document
* whereas Selected Text is generally done by dragging the mouse over a document
* location while holding the left mouse button making the text SELECTED.<br><br>
*
* This method is generally run within a JTextComponent's MouseMove Event but can be
* run from any JTextComponent's Mouse event which will provide the current mouse
* coordinates within the supplied JTextArea Object.
*
* @param textComp (JTextComponent) The JTextComponent object to work on. This
* can be the component variable name for either a JTextField, JTextArea,
* JFormattedField, JPasswordField, JTextPane, and JEditorPane.<br>
*
* @param textAreaMouseXLocation (Integer) The current X Location of the mouse
* pointer. This value can be acquired from the JTextComponent's MouseMove event like
* this <code>int x = evt.getX();</code> where evt is the <b>java.awt.event.MouseEvent</b>
* parameter variable.<br>
*
* @param textAreaMouseYLocation (Integer) The current Y Location of the mouse
* pointer. This value can be acquired from the JTextComponent's MouseMove event like
* this <code>int y = evt.getY();</code> where evt is the <b>java.awt.event.MouseEvent</b>
* parameter variable.<br>
*
* @return (Boolean) True if the text under the current mouse pointer location
* within the supplied JTextComponent is Highlighted and false if it is not.
*/
public static boolean isHighlightededUnderMouse(JTextComponent textComp, int textAreaMouseXLocation,
int textAreaMouseYLocation) {
boolean isHighlighted = false;
if (textComp.getText().isEmpty()) { return false; }
Point pt = new Point(textAreaMouseXLocation, textAreaMouseYLocation);
int pos = textComp.viewToModel(pt);
Highlighter.Highlight[] allHighlights = textComp.getHighlighter().getHighlights();
String strg = "";
for (int i = 0; i < allHighlights.length; i++) {
int start = (int)allHighlights[i].getStartOffset();
int end = (int)allHighlights[i].getEndOffset();
if (pos >= start && pos <= end) {
isHighlighted = true;
break;
}
}
return isHighlighted;
}
/**
* This method will return the "Selected" text contained under the mouse pointer
* location within a JTextComonent.<br><br>
*
* This method is not to be confused with the getHighlightedUnderMouse() method.
* Highlighted text and Selected text are two completely different things.
* Highlighted Text can be text which is Highlighted (generally with a specific
* color) and can be in many different locations throughout the entire document
* whereas Selected Text is generally done by dragging the mouse over a document
* location while holding the left mouse button making the text SELECTED.<br><br>
*
* This method is generally run within a Text Component's MouseMove Event but can be
* run from any Text Component's Mouse event which will provide the current mouse
* coordinates within the supplied Text Component Object.
*
* @param textComp (JTextComponent) The JTextComponent object to work on. This
* can be the component variable name for either a JTextField, JTextArea,
* JFormattedField, JPasswordField, JTextPane, and JEditorPane.<br>
*
* @param textAreaMouseXLocation (Integer) The current X Location of the mouse
* pointer. This value can be acquired from the Text Component's MouseMove event like
* this <code>int x = evt.getX();</code> where evt is the <b>java.awt.event.MouseEvent</b>
* parameter variable.<br>
*
* @param textAreaMouseYLocation (Integer) The current Y Location of the mouse
* pointer. This value can be acquired from the Text Component's MouseMove event like
* this <code>int y = evt.getY();</code> where evt is the <b>java.awt.event.MouseEvent</b>
* parameter variable.<br>
*
* @return (String) The current selected string located under the current mouse
* location.
*/
public static String getSelectededUnderMouse(JTextComponent textComp, int textAreaMouseXLocation,
int textAreaMouseYLocation) {
String selectedText = "";
if (textComp.getText().isEmpty()) { return selectedText; }
Point pt = new Point(textAreaMouseXLocation, textAreaMouseYLocation);
int pos = textComp.viewToModel(pt);
int start = textComp.getSelectionStart();
int end = textComp.getSelectionEnd();
int selectedLength = (end - start);
if (pos >= start && pos <= end) {
try {
selectedText = textComp.getText(start, selectedLength);
}
catch (BadLocationException ex) {
// Ignore!!!
}
}
return selectedText;
}
/**
* This method will return the "Highlighted" text contained under the mouse pointer
* location within a JTextComponent.<br><br>
*
* This method is not to be confused with the getSelectedUnderMouse() method.
* Highlighted text and Selected text are two completely different things.
* Highlighted Text can be text which is Highlighted (generally with a specific
* color) and can be in many different locations throughout the entire document
* whereas Selected Text is generally done by dragging the mouse over a document
* location while holding the left mouse button making the text SELECTED.<br><br>
*
* This method is generally run within a JTextComponent MouseMove Event but can be
* run from any JTextComponent Mouse event which will provide the current mouse
* coordinates within the supplied JTextComponent Object.
*
* @param textComp (JTextComponent) The JTextComponent object to work on. This
* can be the component variable name for either a JTextField, JTextArea,
* JFormattedField, JPasswordField, JTextPane, and JEditorPane.<br>
*
* @param textAreaMouseXLocation (Integer) The current X Location of the mouse
* pointer. This value can be acquired from the JTextComponent's MouseMove event like
* this <code>int x = evt.getX();</code> where evt is the <b>java.awt.event.MouseEvent</b>
* parameter variable.<br>
*
* @param textAreaMouseYLocation (Integer) The current Y Location of the mouse
* pointer. This value can be acquired from the JTextComponent's MouseMove event like
* this <code>int y = evt.getY();</code> where evt is the <b>java.awt.event.MouseEvent</b>
* parameter variable.<br>
*
* @return (String) The current highlighted string located under the current mouse
* location.
*/
public static String getHighlightededUnderMouse(JTextComponent textComp, int textAreaMouseXLocation,
int textAreaMouseYLocation) {
if (textComp.getText().isEmpty()) { return ""; }
Point pnt = new Point(textAreaMouseXLocation, textAreaMouseYLocation);
int pos = textComp.viewToModel(pnt);
String highlightedText = "";
Highlighter.Highlight[] allHighlights = textComp.getHighlighter().getHighlights();
if (allHighlights.length > 0) {
for (int i = 0; i < allHighlights.length; i++) {
int start = (int)allHighlights[i].getStartOffset();
int end = (int)allHighlights[i].getEndOffset();
int hlStringLength = (end-start);
if (pos >= start && pos <= end) {
try {
highlightedText = textComp.getText(start, hlStringLength);
break;
}
catch (BadLocationException ex) {
// Ignore!!!
}
}
}
}
return highlightedText;
}
/**
* This method would normally be called within a JTextComponent's MouseMove Event.
*
* @param textComp (JTextComponent) The JTextComponent object to work on. This
* can be the component variable name for either a JTextField, JTextArea,
* JFormattedField, JPasswordField, JTextPane, and JEditorPane.<br>
*
* @param textAreaMouseXLocation (Integer) The current X Location of the mouse
* pointer. This value can be acquired from the JTextComponent's MouseMove event like
* this <code>int x = evt.getX();</code> where evt is the <b>java.awt.event.MouseEvent</b>
* parameter variable.<br>
*
* @param textAreaMouseYLocation (Integer) The current Y Location of the mouse
* pointer. This value can be acquired from the JTextComponent's MouseMove event like
* this <code>int y = evt.getY();</code> where evt is the <b>java.awt.event.MouseEvent</b>
* parameter variable.<br>
*
* @return (String) The current character located under the current mouse
* location.
*/
public static String getCharUnderMouse(JTextComponent textComp, int textAreaMouseXLocation,
int textAreaMouseYLocation) {
String character = "";
Point pt = new Point(textAreaMouseXLocation, textAreaMouseYLocation);
int pos = textComp.viewToModel(pt);
try {
character = textComp.getDocument().getText(pos, 1);
}
catch (BadLocationException ex) {
// Ignore!!
}
return character;
}
/**
* This method would normally be called within a JTextComponent's MouseMove Event.
*
* @param textComp (JTextArea) The JTextComponent object to work on. This
* can be the component variable name for either a JTextField, JTextArea,
* JFormattedField, JPasswordField, JTextPane, and JEditorPane.<br>
*
* @param textAreaMouseXLocation (Integer) The current X Location of the mouse
* pointer. This value can be acquired from the JTextComponent's MouseMove event like
* this <code>int x = evt.getX();</code> where evt is the <b>java.awt.event.MouseEvent</b>
* parameter variable.<br>
*
* @param textAreaMouseYLocation (Integer) The current Y Location of the mouse
* pointer. This value can be acquired from the JTextComponent's MouseMove event like
* this <code>int y = evt.getY();<code> where evt is the <b>java.awt.event.MouseEvent</b>
* parameter variable.<br>
*
* @return (String) The current Word located under the current mouse location.
*/
public static String getWordUnderMouse(JTextComponent textComp, int textAreaMouseXLocation,
int textAreaMouseYLocation) {
Point pt = new Point(textAreaMouseXLocation, textAreaMouseYLocation);
int pos = textComp.viewToModel(pt);
String word = "";
try {
Document doc = textComp.getDocument();
if( pos > 0 && (pos >= doc.getLength() || Character.isWhitespace( doc.getText( pos, 1 ).charAt( 0 ) )) ) {
// if the next character is a white space then use
// the word on the left side..
pos--;
}
// get the word from current position
final int begOffs = Utilities.getWordStart(textComp, pos);
final int endOffs = Utilities.getWordEnd(textComp, pos);
word = textComp.getText( begOffs, endOffs - begOffs );
}
catch( BadLocationException ex ) {
// Ignore this exception!!!
}
return word;
}