我已经尝试将日志输出到 JTextArea 好几天了，但仍然没有成功。基本上我尝试过的是按照现有的附加程序（如 consoleAppender）创建我自己的自定义附加程序，并尝试在 log4j2.xml 中配置它。我觉得我正朝着正确的方向前进，但不知何故我无法让它发挥作用。我已经在 log4j2 用户邮件列表中询问过，但似乎没有人愿意帮助我。希望我能在这里得到帮助。如果您知道如何实现它，请给我步骤甚至代码片段。
感谢您提前提供的帮助。
好吧，既然有人否决了我的问题，因为它没有表现出任何努力，那么我最好表现出一些努力。我没有展示我所做的任何事情，因为我不太确定我正在做的事情是否正确，人们可能有自己的方法。
我面临的问题是
- 我找不到将该 JTextArea 对象传递给我的 TextAreaAppender 的方法
- 当我尝试运行测试类时，总是收到一个错误，提示 TextArea Appender CLASS_NOT_FOUND，但我已经尝试了所有可能的方法，我可以找到在 log4j2.xml 中指定类属性
代码如下，
文本区域追加器
public class TextAreaAppender extends AbstractOutputStreamAppender<OutputStreamManager>{
private static TextAreaManagerFactory factory = new TextAreaManagerFactory();
public enum Target {
TEXTAREA
}
protected TextAreaAppender(String name, Layout<? extends Serializable> layout, Filter filter,
OutputStreamManager manager, boolean ignoreExceptions) {
super(name, layout, filter, ignoreExceptions, true, manager);
// TODO Auto-generated constructor stub
}
@PluginFactory
public static TextAreaAppender createAppender(
@PluginElement("Layout") Layout<? extends Serializable> layout,
@PluginElement("Filters") final Filter filter,
@PluginAttribute("target") final String t,
@PluginAttribute("name") final String name,
@PluginAttribute("follow") final String follow,
@PluginAttribute("ignoreExceptions") final String ignore) {
if (name == null) {
LOGGER.error("No name provided for TextAreaAppender");
return null;
}
if (layout == null) {
layout = PatternLayout.createLayout(null, null, null, null, null, null);
}
final boolean isFollow = Boolean.parseBoolean(follow);
final boolean ignoreExceptions = Booleans.parseBoolean(ignore, true);
final Target target = t == null ? Target.TEXTAREA : Target.valueOf(t);
return new TextAreaAppender(name, layout, filter, getManager(isFollow, target, layout), ignoreExceptions);
}
private static OutputStreamManager getManager(final boolean follow, final Target target, final Layout<? extends Serializable> layout) {
final String type = target.name();
//should change to getOutputStream(JTextArea),
//but not sure how I can pass textarea object to this class
final OutputStream os = getOutputStream(follow, target);
return OutputStreamManager.getManager(target.name() + "." + follow, new FactoryData(os, type, layout), factory);
}
private static OutputStream getOutputStream(JTextArea ta){
return new TextAreaOutputStream(ta);
}
private static class TextAreaOutputStream extends OutputStream {
private final JTextArea output;
public TextAreaOutputStream(JTextArea ta){
this.output = ta;
}
@Override
public void write(int i) throws IOException{
output.append(String.valueOf((char) i));
}
}
/**
* Data to pass to factory method.
*/
private static class FactoryData {
private final OutputStream os;
private final String type;
private final Layout<? extends Serializable> layout;
/**
* Constructor.
* @param os The OutputStream.
* @param type The name of the target.
* @param layout A Serializable layout
*/
public FactoryData(final OutputStream os, final String type, final Layout<? extends Serializable> layout) {
this.os = os;
this.type = type;
this.layout = layout;
}
}
/**
* Factory to create the Appender.
*/
private static class TextAreaManagerFactory implements ManagerFactory<OutputStreamManager, FactoryData> {
/**
* Create an OutputStreamManager.
* @param name The name of the entity to manage.
* @param data The data required to create the entity.
* @return The OutputStreamManager
*/
@Override
public OutputStreamManager createManager(final String name, final FactoryData data) {
return new TextAreaOutputStreamManager(data.os, data.type, data.layout);// protected constructor???
}
}
private static class TextAreaOutputStreamManager extends OutputStreamManager{
public TextAreaOutputStreamManager(OutputStream os, String name,
Layout<?> layout) {
super(os, name, layout);
// TODO Auto-generated constructor stub
}
}
}
UI测试类
public class Log4j2Example {
class LogModel extends AbstractTableModel{
@Override
public int getColumnCount() {
// TODO Auto-generated method stub
return 1;
}
@Override
public int getRowCount() {
// TODO Auto-generated method stub
return 0;
}
@Override
public Object getValueAt(int rowIndex, int columnIndex) {
// TODO Auto-generated method stub
switch(columnIndex){
case 0: return null;
default: return null;
}
}
}
private final static JTextArea textarea = new JTextArea();
private final LogModel model = new LogModel();
private final JTable table = new JTable(model);
static Log4j2Example INSTANCE = new Log4j2Example();
JFrame frame = new JFrame();
void run(){
frame.setLayout(new BorderLayout());
table.setBorder(new TitledBorder("Table"));
textarea.setBorder(new TitledBorder("Text Area"));
textarea.setPreferredSize(new Dimension(100, 150));
textarea.setEditable(false);
frame.add(table);
frame.add(textarea, BorderLayout.SOUTH);
frame.setVisible(true);
frame.setSize(400, 400);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
static final Logger logger = LogManager.getLogger(Log4j2Example.class.getName());
public static void main(String[] args) {
INSTANCE.run();
System.out.println("test");
logger.trace("Entering Log4j Example.");
Hello hello = new Hello();
if (!hello.callMe()) {
logger.error("Ohh!Failed!");
}
logger.trace("Exiting Log4j Example.");
}
}
log4j2.xml
<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN">
<Appenders>
<Console name="CONSOLE" target="SYSTEM_OUT">
<PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n" />
</Console>
<TextArea name="TextArea" class="testing.Log4j2Example.TextAreaAppender">
<PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n" />
</TextArea>
</Appenders>
<Loggers>
<Logger name="testing.Log4j2Example" level="ALL">
<AppenderRef ref="TextArea"/>
</Logger>
<Root level="ERROR">
<AppenderRef ref="CONSOLE"/>
</Root>
</Loggers>
</Configuration>
