JPasswordField (Java 2 Platform SE v1.4.1) - JDK 5 Documentation v1.4.1, Java 2 SDK 英文文档

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Java^TM 2 Platform
Std. Ed. v1.4.1

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javax.swing
Class JPasswordField

java.lang.Object
  |
  +--java.awt.Component
        |
        +--java.awt.Container
              |
              +--javax.swing.JComponent
                    |
                    +--javax.swing.text.JTextComponent
                          |
                          +--javax.swing.JTextField
                                |
                                +--javax.swing.JPasswordField

All Implemented Interfaces:: Accessible, ImageObserver, MenuContainer, Scrollable, Serializable, SwingConstants

public class JPasswordField
extends JTextField

JPasswordField is a lightweight component that allows the editing of a single line of text where the view indicates something was typed, but does not show the original characters. You can find further information and examples in How to Use Text Fields, a section in The Java Tutorial.

JPasswordField is intended to be source-compatible with java.awt.TextField used with echoChar set. It is provided separately to make it easier to safely change the UI for the JTextField without affecting password entries.

For the keyboard keys used by this component in the standard Look and Feel (L&F) renditions, see the JPasswordField key assignments.

Warning: Serialized objects of this class will not be compatible with future Swing releases. The current serialization support is appropriate for short term storage or RMI between applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeans^TM has been added to the java.beans package. Please see XMLEncoder.

Constructor Detail

JPasswordField

public JPasswordField()

Constructs a new JPasswordField, with a default document, null starting text string, and 0 column width.

JPasswordField

public JPasswordField(String text)

Constructs a new JPasswordField initialized with the specified text. The document model is set to the default, and the number of columns to 0.
Parameters:: text - the text to be displayed, null if none

JPasswordField

public JPasswordField(int columns)

Constructs a new empty JPasswordField with the specified number of columns. A default model is created, and the initial string is set to null.
Parameters:: columns - the number of columns >= 0

JPasswordField

public JPasswordField(String text,
                      int columns)

Constructs a new JPasswordField initialized with the specified text and columns. The document model is set to the default.
Parameters:: text - the text to be displayed, null if none; columns - the number of columns >= 0

JPasswordField

public JPasswordField(Document doc,
                      String txt,
                      int columns)

Constructs a new JPasswordField that uses the given text storage model and the given number of columns. This is the constructor through which the other constructors feed. The echo character is set to '*'. If the document model is null, a default one will be created.
Parameters:: doc - the text storage to use; txt - the text to be displayed, null if none; columns - the number of columns to use to calculate the preferred width >= 0; if columns is set to zero, the preferred width will be whatever naturally results from the component implementation

Method Detail

getUIClassID

public String getUIClassID()

Returns the name of the L&F class that renders this component.

Overrides:: getUIClassID in class JTextField

Returns:: the string "PasswordFieldUI"
See Also:: JComponent.getUIClassID(), UIDefaults.getUI(javax.swing.JComponent)

getEchoChar

public char getEchoChar()

Returns the character to be used for echoing. The default is '*'.

Returns:: the echo character, 0 if unset
See Also:: setEchoChar(char), echoCharIsSet()

setEchoChar

public void setEchoChar(char c)

Sets the echo character for this JPasswordField. Note that this is largely a suggestion, since the view that gets installed can use whatever graphic techniques it desires to represent the field. Setting a value of 0 indicates that you wish to see the text as it is typed, similar to the behavior of a standard JTextField.

Parameters:: c - the echo character to display
See Also:: echoCharIsSet(), getEchoChar()

echoCharIsSet

public boolean echoCharIsSet()

Returns true if this JPasswordField has a character set for echoing. A character is considered to be set if the echo character is not 0.

Returns:: true if a character is set for echoing
See Also:: setEchoChar(char), getEchoChar()

cut

public void cut()

Invokes provideErrorFeedback on the current look and feel, which typically initiates an error beep. The normal behavior of transferring the currently selected range in the associated text model to the system clipboard, and removing the contents from the model, is not acceptable for a password field.

Overrides:: cut in class JTextComponent

See Also:: Toolkit.getSystemClipboard(), Clipboard

copy

public void copy()

Invokes provideErrorFeedback on the current look and feel, which typically initiates an error beep. The normal behavior of transferring the currently selected range in the associated text model to the system clipboard, and leaving the contents from the model, is not acceptable for a password field.

Overrides:: copy in class JTextComponent

See Also:: Toolkit.getSystemClipboard(), Clipboard

getText

public String getText()

Deprecated. As of Java 2 platform v1.2, replaced by getPassword.

Returns the text contained in this TextComponent. If the underlying document is null, will give a NullPointerException.

For security reasons, this method is deprecated. Use the * getPassword method instead.

Overrides:: getText in class JTextComponent

Returns:: the text
See Also:: JTextComponent.setText(java.lang.String)

getText

public String getText(int offs,
                      int len)
               throws BadLocationException

Deprecated. As of Java 2 platform v1.2, replaced by getPassword.

Fetches a portion of the text represented by the component. Returns an empty string if length is 0.

For security reasons, this method is deprecated. Use the getPassword method instead.

Overrides:: getText in class JTextComponent

Parameters:: offs - the offset >= 0; len - the length >= 0
Returns:: the text
Throws:: BadLocationException - if the offset or length are invalid

getPassword

public char[] getPassword()

Returns the text contained in this TextComponent. If the underlying document is null, will give a NullPointerException. For stronger security, it is recommended that the returned character array be cleared after use by setting each character to zero.

Returns:: the text

paramString

protected String paramString()

Returns a string representation of this JPasswordField. This method is intended to be used only for debugging purposes, and the content and format of the returned string may vary between implementations. The returned string may be empty but may not be null.

Overrides:: paramString in class JTextField

Returns:: a string representation of this JPasswordField

getAccessibleContext

public AccessibleContext getAccessibleContext()

Returns the AccessibleContext associated with this JPasswordField. For password fields, the AccessibleContext takes the form of an AccessibleJPasswordField. A new AccessibleJPasswordField instance is created if necessary.

Specified by:: getAccessibleContext in interface Accessible
Overrides:: getAccessibleContext in class JTextField

Returns:: an AccessibleJPasswordField that serves as the AccessibleContext of this JPasswordField

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For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

Nested Class Summary
`protected class`	`JPasswordField.AccessibleJPasswordField` This class implements accessibility support for the `JPasswordField` class.

Constructor Summary
`JPasswordField()` Constructs a new `JPasswordField`, with a default document, `null` starting text string, and 0 column width.
`JPasswordField(Document doc, String txt, int columns)` Constructs a new `JPasswordField` that uses the given text storage model and the given number of columns.
`JPasswordField(int columns)` Constructs a new empty `JPasswordField` with the specified number of columns.
`JPasswordField(String text)` Constructs a new `JPasswordField` initialized with the specified text.
`JPasswordField(String text, int columns)` Constructs a new `JPasswordField` initialized with the specified text and columns.

Method Summary
`void`	`copy()` Invokes `provideErrorFeedback` on the current look and feel, which typically initiates an error beep.
`void`	`cut()` Invokes `provideErrorFeedback` on the current look and feel, which typically initiates an error beep.
`boolean`	`echoCharIsSet()` Returns true if this `JPasswordField` has a character set for echoing.
`AccessibleContext`	`getAccessibleContext()` Returns the `AccessibleContext` associated with this `JPasswordField`.
`char`	`getEchoChar()` Returns the character to be used for echoing.
`char[]`	`getPassword()` Returns the text contained in this `TextComponent`.
`String`	`getText()` Deprecated. As of Java 2 platform v1.2, replaced by `getPassword`.
`String`	`getText(int offs, int len)` Deprecated. As of Java 2 platform v1.2, replaced by `getPassword`.
`String`	`getUIClassID()` Returns the name of the L&F class that renders this component.
`protected String`	`paramString()` Returns a string representation of this `JPasswordField`.
`void`	`setEchoChar(char c)` Sets the echo character for this `JPasswordField`.

JPasswordField (Java 2 Platform SE v1.4.1) - JDK 5 Documentation v1.4.1, Java 2 SDK 英文文档

javax.swing Class JPasswordField

JPasswordField

JPasswordField

JPasswordField

JPasswordField

JPasswordField

getUIClassID

getEchoChar

setEchoChar

echoCharIsSet

cut

copy

getText

getText

getPassword

paramString

getAccessibleContext

javax.swing
Class JPasswordField