Java 如何在log4j2中实现自定义模式布局

我正在将我的应用程序从

log4j

迁移到

log4j2

API。迁移时，我发现使用了

自定义

模式布局

，

模式解析器

和

模式转换器

。我不知道如何使用log4j2插件实现这些更改。有谁能帮我把这个自定义布局

testpatternalyout

转换成log4j2吗。非常感谢

PFB关于如何使用

log4j

实现自定义图案布局的完整详细信息

测试模式布局：

public class TestPatternLayout extends PatternLayout {

@Override 
protected PatternParser createPatternParser(String pattern) { 
    return new TestPatternParser(pattern); 
 } 
}

public class TestPatternParser extends PatternParser {

private static final char Test_CHAR = 'e';
private static final char DATETIME_CHAR = 'd';

public TestPatternParser(String pattern) {
    super(pattern);
}

@Override
protected void finalizeConverter(char c) {
    switch (c) {
        case Test_CHAR:
            currentLiteral.setLength(0);
            addConverter(new TestPatternConverter());
            break;            
        default:
            super.finalizeConverter(c);
    }
 }
}

public class TestPatternConverter extends PatternConverter {

@Override
protected String convert(LoggingEvent event) {
    String testID = ObjectUtils.EMPTY_STRING;
    if(TestLogHandler.isTestLogEnabled()) {
        TestContextHolder contextHolder = TestLogHandler.getLatestContextHolderFromStack(event.getThreadName());
        if(contextHolder != null) {
            testID = contextHolder.getTestIDForThread(event.getThreadName());
        }
        else{
            testID = TestContextHolder.getTestIDForThread(event.getThreadName());
        }
    }
    return testID;
 }
}

<appender name="TEST_LOG_FILE" class="org.apache.log4j.RollingFileAppender">
...
   <layout class="com.test.it.logging.TestPatternLayout">
      <param name="ConversionPattern" value="%d %-5p [%c{1}] [TestId: %e] [%t] %m%n"/>
</layout>
...
</appender>

TestPatternParser:

public class TestPatternLayout extends PatternLayout {

@Override 
protected PatternParser createPatternParser(String pattern) { 
    return new TestPatternParser(pattern); 
 } 
}

public class TestPatternParser extends PatternParser {

private static final char Test_CHAR = 'e';
private static final char DATETIME_CHAR = 'd';

public TestPatternParser(String pattern) {
    super(pattern);
}

@Override
protected void finalizeConverter(char c) {
    switch (c) {
        case Test_CHAR:
            currentLiteral.setLength(0);
            addConverter(new TestPatternConverter());
            break;            
        default:
            super.finalizeConverter(c);
    }
 }
}

public class TestPatternConverter extends PatternConverter {

@Override
protected String convert(LoggingEvent event) {
    String testID = ObjectUtils.EMPTY_STRING;
    if(TestLogHandler.isTestLogEnabled()) {
        TestContextHolder contextHolder = TestLogHandler.getLatestContextHolderFromStack(event.getThreadName());
        if(contextHolder != null) {
            testID = contextHolder.getTestIDForThread(event.getThreadName());
        }
        else{
            testID = TestContextHolder.getTestIDForThread(event.getThreadName());
        }
    }
    return testID;
 }
}

<appender name="TEST_LOG_FILE" class="org.apache.log4j.RollingFileAppender">
...
   <layout class="com.test.it.logging.TestPatternLayout">
      <param name="ConversionPattern" value="%d %-5p [%c{1}] [TestId: %e] [%t] %m%n"/>
</layout>
...
</appender>

测试模式转换器：

public class TestPatternLayout extends PatternLayout {

@Override 
protected PatternParser createPatternParser(String pattern) { 
    return new TestPatternParser(pattern); 
 } 
}

public class TestPatternParser extends PatternParser {

private static final char Test_CHAR = 'e';
private static final char DATETIME_CHAR = 'd';

public TestPatternParser(String pattern) {
    super(pattern);
}

@Override
protected void finalizeConverter(char c) {
    switch (c) {
        case Test_CHAR:
            currentLiteral.setLength(0);
            addConverter(new TestPatternConverter());
            break;            
        default:
            super.finalizeConverter(c);
    }
 }
}

public class TestPatternConverter extends PatternConverter {

@Override
protected String convert(LoggingEvent event) {
    String testID = ObjectUtils.EMPTY_STRING;
    if(TestLogHandler.isTestLogEnabled()) {
        TestContextHolder contextHolder = TestLogHandler.getLatestContextHolderFromStack(event.getThreadName());
        if(contextHolder != null) {
            testID = contextHolder.getTestIDForThread(event.getThreadName());
        }
        else{
            testID = TestContextHolder.getTestIDForThread(event.getThreadName());
        }
    }
    return testID;
 }
}

<appender name="TEST_LOG_FILE" class="org.apache.log4j.RollingFileAppender">
...
   <layout class="com.test.it.logging.TestPatternLayout">
      <param name="ConversionPattern" value="%d %-5p [%c{1}] [TestId: %e] [%t] %m%n"/>
</layout>
...
</appender>

log4j.xml中的布局定义：

public class TestPatternLayout extends PatternLayout {

@Override 
protected PatternParser createPatternParser(String pattern) { 
    return new TestPatternParser(pattern); 
 } 
}

public class TestPatternParser extends PatternParser {

private static final char Test_CHAR = 'e';
private static final char DATETIME_CHAR = 'd';

public TestPatternParser(String pattern) {
    super(pattern);
}

@Override
protected void finalizeConverter(char c) {
    switch (c) {
        case Test_CHAR:
            currentLiteral.setLength(0);
            addConverter(new TestPatternConverter());
            break;            
        default:
            super.finalizeConverter(c);
    }
 }
}

public class TestPatternConverter extends PatternConverter {

@Override
protected String convert(LoggingEvent event) {
    String testID = ObjectUtils.EMPTY_STRING;
    if(TestLogHandler.isTestLogEnabled()) {
        TestContextHolder contextHolder = TestLogHandler.getLatestContextHolderFromStack(event.getThreadName());
        if(contextHolder != null) {
            testID = contextHolder.getTestIDForThread(event.getThreadName());
        }
        else{
            testID = TestContextHolder.getTestIDForThread(event.getThreadName());
        }
    }
    return testID;
 }
}

<appender name="TEST_LOG_FILE" class="org.apache.log4j.RollingFileAppender">
...
   <layout class="com.test.it.logging.TestPatternLayout">
      <param name="ConversionPattern" value="%d %-5p [%c{1}] [TestId: %e] [%t] %m%n"/>
</layout>
...
</appender>

...
...

您只需创建一个新的

插件

并扩展

LogEventPatternConverter

：

@Plugin(name = "TestPatternConverter", category = PatternConverter.CATEGORY)
@ConverterKeys({"e"})
public final class TestPatternConverter extends LogEventPatternConverter {

    /**
     * Private constructor.
     * @param options options, may be null.
     */
    private TestPatternConverter(final String[] options) {
        super("TestId", "testId");
    }

    /**
     * Obtains an instance of pattern converter.
     *
     * @param options options, may be null.
     * @return instance of pattern converter.
     */
    public static TestPatternConverter newInstance(final String[] options) {
        return new TestPatternConverter(options);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void format(final LogEvent event, final StringBuilder toAppendTo) {
        String testID = ObjectUtils.EMPTY_STRING;
        if(TestLogHandler.isTestLogEnabled()) {
            TestContextHolder contextHolder = TestLogHandler.getLatestContextHolderFromStack(event.getThreadName());
            if(contextHolder != null) {
                testID = contextHolder.getTestIDForThread(event.getThreadName());
            }
            else{
                testID = TestContextHolder.getTestIDForThread(event.getThreadName());
            }
        }
        toAppendTo.append(testID);
    }
}

并更新您的配置：

<Appender type="RollingFile" name="TEST_LOG_FILE" fileName="${filename}">
      <Layout type="PatternLayout">
        <Pattern>%d %-5p [%c{1}] [TestId: %e] [%t] %m%n</Pattern>
      </Layout>
</Appender>

了解更多详细信息。
回答得很好！是否可以使用此选项隐藏/取消隐藏throwable的消息？