扩展logback DBAppender

[b]一) logback已经提供了一个DBAppender(ch.qos.logback.classic.db.DBAppender)，为何还需自己发明一个轮子?[/b]

1.1
ch.qos.logback.classic.db.DBAppender默认只能保存4个参数到数据库里，如下
(slf4j代码)

LOGGER.info("{}{}{}{}{}", 1,2,3,4,5);

参数5不能保存在DB中的单独一个字段，这样并不方便。扩展为可以保存32个参数。

1.2
logback默认的DBAppender不方便配置，不能自由指定表名

1.3
logback默认的DBAppender中保存的时间戳为long，阅读时不方便。

[b]二) 代码片段 (仅新的DBAppender类，其他工具类等为节省篇幅不贴出)[/b]

package com.github.yingzhuo.logbackext.db;import java.lang.reflect.Method;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.SQLException;import java.text.DateFormat;import java.text.SimpleDateFormat;import java.util.Date;import java.util.HashMap;import java.util.Iterator;import java.util.Map;import java.util.Set;import ch.qos.logback.classic.db.DBHelper;import ch.qos.logback.classic.spi.CallerData;import ch.qos.logback.classic.spi.ILoggingEvent;import ch.qos.logback.classic.spi.IThrowableProxy;import ch.qos.logback.classic.spi.StackTraceElementProxy;import ch.qos.logback.classic.spi.ThrowableProxyUtil;import ch.qos.logback.core.CoreConstants;import ch.qos.logback.core.db.DBAppenderBase;import ch.qos.logback.core.db.dialect.SQLDialectCode;import com.github.yingzhuo.logbackext.names.DefaultTableAndColumnNameResolver;import com.github.yingzhuo.logbackext.names.TableAndColumnNameResolver;/** * 参考ch.qos.logback.classic.db.DBAppender *  * @author yingzhuo *  */@SuppressWarnings("rawtypes")public class DBAppender extends DBAppenderBase<ILoggingEvent> {	private static final DateFormat DATE_FORMAT = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss.SSS");	private boolean printStackTrace = true;	protected String insertPropertiesSQL;	protected String insertExceptionSQL;	protected String insertSQL;	protected static final Method GET_GENERATED_KEYS_METHOD;	private TableAndColumnNameResolver nameResolver = new DefaultTableAndColumnNameResolver();	static final int TIMESTMP_INDEX = 1;	static final int FORMATTED_MESSAGE_INDEX = 2;	static final int LOGGER_NAME_INDEX = 3;	static final int LEVEL_STRING_INDEX = 4;	static final int THREAD_NAME_INDEX = 5;	static final int REFERENCE_FLAG_INDEX = 6;	static final int ARG0_INDEX = 7;	static final int ARG1_INDEX = 8;	static final int ARG2_INDEX = 9;	static final int ARG3_INDEX = 10;	static final int ARG4_INDEX = 11;	static final int ARG5_INDEX = 12;	static final int ARG6_INDEX = 13;	static final int ARG7_INDEX = 14;	static final int ARG8_INDEX = 15;	static final int ARG9_INDEX = 16;	static final int ARG10_INDEX = 17;	static final int ARG11_INDEX = 18;	static final int ARG12_INDEX = 19;	static final int ARG13_INDEX = 20;	static final int ARG14_INDEX = 21;	static final int ARG15_INDEX = 22;	static final int ARG16_INDEX = 23;	static final int ARG17_INDEX = 24;	static final int ARG18_INDEX = 25;	static final int ARG19_INDEX = 26;	static final int ARG20_INDEX = 27;	static final int ARG21_INDEX = 28;	static final int ARG22_INDEX = 29;	static final int ARG23_INDEX = 30;	static final int ARG24_INDEX = 31;	static final int ARG25_INDEX = 32;	static final int ARG26_INDEX = 33;	static final int ARG27_INDEX = 34;	static final int ARG28_INDEX = 35;	static final int ARG29_INDEX = 36;	static final int ARG30_INDEX = 37;	static final int ARG31_INDEX = 38;	static final int CALLER_FILENAME_INDEX = 39;	static final int CALLER_CLASS_INDEX = 40;	static final int CALLER_METHOD_INDEX = 41;	static final int CALLER_LINE_INDEX = 42;	static final int EVENT_ID_INDEX = 43;	static final StackTraceElement EMPTY_CALLER_DATA = CallerData.naInstance();	static {		Method getGeneratedKeysMethod;		try {			getGeneratedKeysMethod = PreparedStatement.class.getMethod("getGeneratedKeys", (Class[]) null);		} catch (Exception ex) {			getGeneratedKeysMethod = null;		}		GET_GENERATED_KEYS_METHOD = getGeneratedKeysMethod;	}	@Override	public void start() {		insertExceptionSQL = SQLBuilder.buildInsertExceptionSQL(nameResolver);		insertPropertiesSQL = SQLBuilder.buildInsertPropertiesSQL(nameResolver);		insertSQL = SQLBuilder.buildInsertSQL(nameResolver);		System.out.println(insertSQL);		super.start();	}	@Override	protected void subAppend(ILoggingEvent event, Connection connection, PreparedStatement insertStatement) throws Throwable {		bindLoggingEventWithInsertStatement(insertStatement, event);		bindLoggingEventArgumentsWithPreparedStatement(insertStatement, event.getArgumentArray());		bindCallerDataWithPreparedStatement(insertStatement, event.getCallerData());		int updateCount = 0;		try {			updateCount = insertStatement.executeUpdate();		} catch (Exception e) {			if (this.printStackTrace) {				e.printStackTrace();			}			throw e;		}		if (updateCount != 1) {			addWarn("Failed to insert loggingEvent");		}	}	protected void secondarySubAppend(ILoggingEvent event, Connection connection, long eventId) throws Throwable {		Map<String, String> mergedMap = mergePropertyMaps(event);		insertProperties(mergedMap, connection, eventId);		if (event.getThrowableProxy() != null) {			insertThrowable(event.getThrowableProxy(), connection, eventId);		}	}	void bindLoggingEventWithInsertStatement(PreparedStatement stmt, ILoggingEvent event) throws SQLException {		stmt.setString(TIMESTMP_INDEX, DATE_FORMAT.format(new Date(event.getTimeStamp())));		stmt.setString(FORMATTED_MESSAGE_INDEX, event.getFormattedMessage());		stmt.setString(LOGGER_NAME_INDEX, event.getLoggerName());		stmt.setString(LEVEL_STRING_INDEX, event.getLevel().toString());		stmt.setString(THREAD_NAME_INDEX, event.getThreadName());		stmt.setShort(REFERENCE_FLAG_INDEX, DBHelper.computeReferenceMask(event));	}	void bindLoggingEventArgumentsWithPreparedStatement(PreparedStatement stmt, Object[] argArray) throws SQLException {		int arrayLen = argArray != null ? argArray.length : 0;		for (int i = 0; i < arrayLen && i < 32; i++) {			stmt.setString(ARG0_INDEX + i, asStringTruncatedTo254(argArray[i]));		}		if (arrayLen < 32) {			for (int i = arrayLen; i < 32; i++) {				stmt.setString(ARG0_INDEX + i, null);			}		}	}	String asStringTruncatedTo254(Object o) {		String s = null;		if (o != null) {			s = o.toString();		}		if (s == null) {			return null;		}		if (s.length() <= 254) {			return s;		} else {			return s.substring(0, 254);		}	}	void bindCallerDataWithPreparedStatement(PreparedStatement stmt, StackTraceElement[] callerDataArray) throws SQLException {		StackTraceElement caller = extractFirstCaller(callerDataArray);		stmt.setString(CALLER_FILENAME_INDEX, caller.getFileName());		stmt.setString(CALLER_CLASS_INDEX, caller.getClassName());		stmt.setString(CALLER_METHOD_INDEX, caller.getMethodName());		stmt.setString(CALLER_LINE_INDEX, Integer.toString(caller.getLineNumber()));	}	private StackTraceElement extractFirstCaller(StackTraceElement[] callerDataArray) {		StackTraceElement caller = EMPTY_CALLER_DATA;		if (hasAtLeastOneNonNullElement(callerDataArray))			caller = callerDataArray[0];		return caller;	}	private boolean hasAtLeastOneNonNullElement(StackTraceElement[] callerDataArray) {		return callerDataArray != null && callerDataArray.length > 0				&& callerDataArray[0] != null;	}	Map<String, String> mergePropertyMaps(ILoggingEvent event) {		Map<String, String> mergedMap = new HashMap<String, String>();		Map<String, String> loggerContextMap = event.getLoggerContextVO().getPropertyMap();		Map<String, String> mdcMap = event.getMDCPropertyMap();		if (loggerContextMap != null) {			mergedMap.putAll(loggerContextMap);		}		if (mdcMap != null) {			mergedMap.putAll(mdcMap);		}		return mergedMap;	}	@Override	protected Method getGeneratedKeysMethod() {		return GET_GENERATED_KEYS_METHOD;	}	@Override	protected String getInsertSQL() {		return insertSQL;	}	protected void insertProperties(Map<String, String> mergedMap, Connection connection, long eventId) throws SQLException {		Set propertiesKeys = mergedMap.keySet();		if (propertiesKeys.size() > 0) {			PreparedStatement insertPropertiesStatement = connection.prepareStatement(insertPropertiesSQL);			for (Iterator i = propertiesKeys.iterator(); i.hasNext();) {				String key = (String) i.next();				String value = (String) mergedMap.get(key);				insertPropertiesStatement.setLong(1, eventId);				insertPropertiesStatement.setString(2, key);				insertPropertiesStatement.setString(3, value);				if (cnxSupportsBatchUpdates) {					insertPropertiesStatement.addBatch();				} else {					insertPropertiesStatement.execute();				}			}			if (cnxSupportsBatchUpdates) {				insertPropertiesStatement.executeBatch();			}			insertPropertiesStatement.close();		}	}	void updateExceptionStatement(PreparedStatement exceptionStatement, String txt, short i, long eventId) throws SQLException {		exceptionStatement.setLong(1, eventId);		exceptionStatement.setShort(2, i);		exceptionStatement.setString(3, txt);		if (cnxSupportsBatchUpdates) {			exceptionStatement.addBatch();		} else {			exceptionStatement.execute();		}	}	short buildExceptionStatement(IThrowableProxy tp, short baseIndex,			PreparedStatement insertExceptionStatement, long eventId)			throws SQLException {		StringBuilder buf = new StringBuilder();		ThrowableProxyUtil.subjoinFirstLine(buf, tp);		updateExceptionStatement(insertExceptionStatement, buf.toString(), baseIndex++, eventId);		int commonFrames = tp.getCommonFrames();		StackTraceElementProxy[] stepArray = tp.getStackTraceElementProxyArray();		for (int i = 0; i < stepArray.length - commonFrames; i++) {			StringBuilder sb = new StringBuilder();			sb.append(CoreConstants.TAB);			ThrowableProxyUtil.subjoinSTEP(sb, stepArray[i]);			updateExceptionStatement(insertExceptionStatement, sb.toString(), baseIndex++, eventId);		}		if (commonFrames > 0) {			StringBuilder sb = new StringBuilder();			sb.append(CoreConstants.TAB).append("... ").append(commonFrames)					.append(" common frames omitted");			updateExceptionStatement(insertExceptionStatement, sb.toString(),					baseIndex++, eventId);		}		return baseIndex;	}	protected void insertThrowable(IThrowableProxy tp, Connection connection, long eventId) throws SQLException {		PreparedStatement exceptionStatement = connection.prepareStatement(insertExceptionSQL);		short baseIndex = 0;		while (tp != null) {			baseIndex = buildExceptionStatement(tp, baseIndex, exceptionStatement, eventId);			tp = tp.getCause();		}		if (cnxSupportsBatchUpdates) {			exceptionStatement.executeBatch();		}		exceptionStatement.close();	}	public boolean isPrintStackTrace() {		return printStackTrace;	}	public void setPrintStackTrace(boolean printStackTrace) {		this.printStackTrace = printStackTrace;	}	public TableAndColumnNameResolver getNameResolver() {		return nameResolver;	}	public void setNameResolver(TableAndColumnNameResolver nameResolver) {		this.nameResolver = nameResolver;	}	@Override	public void append(ILoggingEvent eventObject) {		Connection connection = null;		try {			connection = connectionSource.getConnection();			connection.setAutoCommit(false);			PreparedStatement insertStatement;			if (cnxSupportsGetGeneratedKeys) {				String EVENT_ID_COL_NAME = "EVENT_ID";				if (connectionSource.getSQLDialectCode() == SQLDialectCode.POSTGRES_DIALECT) {					EVENT_ID_COL_NAME = EVENT_ID_COL_NAME.toLowerCase();				}				insertStatement = connection.prepareStatement(getInsertSQL(), new String[] { EVENT_ID_COL_NAME });			} else {				insertStatement = connection.prepareStatement(getInsertSQL());			}			long eventId;			synchronized (this) {				subAppend(eventObject, connection, insertStatement);				eventId = 						selectEventId(insertStatement, connection);			}			secondarySubAppend(eventObject, connection, eventId);			insertStatement.close();			connection.commit();		} catch (Throwable sqle) {			if (this.printStackTrace) {				sqle.printStackTrace();			}			addError("problem appending event", sqle);		} finally {			try { connection.close();} catch (SQLException e) {}		}	}}

[b]三) 配置 (logback.xml片段)[/b]

<appender name="DB" class="com.github.yingzhuo.logbackext.db.DBAppender">	<connectionSource class="ch.qos.logback.core.db.DriverManagerConnectionSource">		<dataSource class="com.mchange.v2.c3p0.ComboPooledDataSource">			<driverClass>com.mysql.jdbc.Driver</driverClass>			<url>jdbc:mysql://127.0.0.1:3306/logback</url>			<user>root</user>			<password>root</password>		</dataSource>	</connectionSource>	<nameResolver class="com.github.yingzhuo.logbackext.names.DefaultTableAndColumnNameResolver">		<loggingEventTableName>last</loggingEventTableName>		<loggingEventExceptionTableName>last_exception</loggingEventExceptionTableName>		<loggingEventPropertyTableName>last_property</loggingEventPropertyTableName>	</nameResolver>	<printStackTrace>true</printStackTrace></appender>

[b]四) 下载安装[/b]
这是一个maven项目，源代码已经发布到GitHub
[url]https://github.com/yingzhuo/logback-ext[/url]