Logback是log4j的增强版，比log4j更具灵活，其提供了将日志输出到数据库的功能，本文将介绍如何将指定的日志输出到mysql中。
一、自定义log标志
由于Logback原生的配置会将所有的日志信息输出到mysql数据表中，故需要自定义标志，继承AbstractMatcherFilter，过滤掉无标志的日志：
1、自定义标志过滤器
public class LogbackMarkerFilter extends AbstractMatcherFilter<ILoggingEvent> {
private Marker markerToMatch = null;
@Override
public void start() {
if (null != this.markerToMatch) {
super.start();
} else {
addError(" no MARKER yet !");
}
}
@Override
public FilterReply decide(ILoggingEvent event) {
Marker marker = event.getMarker();
if (!isStarted()) {
return FilterReply.NEUTRAL;
}
if (null == marker) {
return onMismatch;
}
if (markerToMatch.contains(marker)) {
return onMatch;
}
return onMismatch;
}
public void setMarker(String markerStr) {
if (null != markerStr) {
markerToMatch = MarkerFactory.getMarker(markerStr);
}
}
}
2、logback-spring.xml 相关配置文件
<!-- 数据库日志记录 -->
<appender name="DB_APPENDER" class="ch.qos.logback.classic.db.DBAppender">
<filter class="com.cenobitor.logging.filter.LogbackMarkerFilter">
<!-- 自定义标志 -->
<marker>DB</marker>
<onMatch>ACCEPT</onMatch>
<onMismatch>DENY</onMismatch>
</filter>
<!-- 配置数据源 springboot默认情况会开启光连接池 -->
<connectionSource class="ch.qos.logback.core.db.DriverManagerConnectionSource">
<driverClass>${driverClass}</driverClass>
<url>${url}</url>
<user>${username}</user>
<password>${password}</password>
</connectionSource>
</appender>
<!-- 异步日志记录 -->
<appender name="ASYNC_APPENDER" class="ch.qos.logback.classic.AsyncAppender">
<appender-ref ref="DB_APPENDER" />
<includeCallerData>true</includeCallerData>
</appender>
<!-- 日志输出级别 -->
<root level="${LOG_LEVEL}">
<appender-ref ref="ASYNC_APPENDER" />
</root>
经配置，其需要建三张数据表，分别为日志信息、异常信息、属性信息，其建表语句如下：
BEGIN;
DROP TABLE IF EXISTS logging_event_property;
DROP TABLE IF EXISTS logging_event_exception;
DROP TABLE IF EXISTS logging_event;
COMMIT;
BEGIN;
CREATE TABLE logging_event
(
timestmp BIGINT NOT NULL,
formatted_message TEXT NOT NULL,
logger_name VARCHAR(254) NOT NULL,
level_string VARCHAR(254) NOT NULL,
thread_name VARCHAR(254),
reference_flag SMALLINT,
arg0 VARCHAR(254),
arg1 VARCHAR(254),
arg2 VARCHAR(254),
arg3 VARCHAR(254),
caller_filename VARCHAR(254) NOT NULL,
caller_class VARCHAR(254) NOT NULL,
caller_method VARCHAR(254) NOT NULL,
caller_line CHAR(4) NOT NULL,
event_id BIGINT NOT NULL AUTO_INCREMENT PRIMARY KEY
);
COMMIT;
BEGIN;
CREATE TABLE logging_event_property
(
event_id BIGINT NOT NULL,
mapped_key VARCHAR(254) NOT NULL,
mapped_value TEXT,
PRIMARY KEY(event_id, mapped_key),
FOREIGN KEY (event_id) REFERENCES logging_event(event_id)
);
COMMIT;
BEGIN;
CREATE TABLE logging_event_exception
(
event_id BIGINT NOT NULL,
i SMALLINT NOT NULL,
trace_line VARCHAR(254) NOT NULL,
PRIMARY KEY(event_id, i),
FOREIGN KEY (event_id) REFERENCES logging_event(event_id)
);
COMMIT;
二、自定义输出日志
由于Logback原生要求建三张表，如何指定指输出一种信息，及自定义日志内容，而异常、属性信息不输出？
通过查看DBAppender发现，插入数据方法，此处只需重写DBAppender，即继承DBAppenderBase<ILoggingEvent>，删除掉异常、属性信息插入的相关方法即可实现只输出指定日志到指定表，而其它信息将不会输出到数据库中，代码如下：
public class LogDBAppender extends DBAppenderBase<ILoggingEvent> {
protected String insertSQL;
protected static final Method GET_GENERATED_KEYS_METHOD;
private DBNameResolver dbNameResolver;
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 CALLER_FILENAME_INDEX = 11;
static final int CALLER_CLASS_INDEX = 12;
static final int CALLER_METHOD_INDEX = 13;
static final int CALLER_LINE_INDEX = 14;
static final int EVENT_ID_INDEX = 15;
static final StackTraceElement EMPTY_CALLER_DATA = CallerData.naInstance();
static {
// PreparedStatement.getGeneratedKeys() method was added in JDK 1.4
Method getGeneratedKeysMethod;
try {
// the
getGeneratedKeysMethod = PreparedStatement.class.getMethod("getGeneratedKeys", (Class[]) null);
} catch (Exception ex) {
getGeneratedKeysMethod = null;
}
GET_GENERATED_KEYS_METHOD = getGeneratedKeysMethod;
}
public void setDbNameResolver(DBNameResolver dbNameResolver) {
this.dbNameResolver = dbNameResolver;
}
@Override
public void start() {
if (dbNameResolver == null)
dbNameResolver = new DefaultDBNameResolver();
insertSQL = buildInsertSQL(dbNameResolver);
super.start();
}
@Override
protected void subAppend(ILoggingEvent event, Connection connection, PreparedStatement insertStatement) throws Throwable {
bindLoggingEventWithInsertStatement(insertStatement, event);
bindLoggingEventArgumentsWithPreparedStatement(insertStatement, event.getArgumentArray());
// This is expensive... should we do it every time?
bindCallerDataWithPreparedStatement(insertStatement, event.getCallerData());
int updateCount = insertStatement.executeUpdate();
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.setLong(TIMESTMP_INDEX, 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 < 4; i++) {
stmt.setString(ARG0_INDEX + i, asStringTruncatedTo254(argArray[i]));
}
if (arrayLen < 4) {
for (int i = arrayLen; i < 4; 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>();
// we add the context properties first, then the event properties, since
// we consider that event-specific properties should have priority over
// context-wide properties.
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;
}
static String buildInsertSQL(DBNameResolver dbNameResolver) {
StringBuilder sqlBuilder = new StringBuilder("INSERT INTO ");
sqlBuilder.append(dbNameResolver.getTableName(TableName.LOGGING_EVENT)).append(" (");
sqlBuilder.append(dbNameResolver.getColumnName(ColumnName.TIMESTMP)).append(", ");
sqlBuilder.append(dbNameResolver.getColumnName(ColumnName.FORMATTED_MESSAGE)).append(", ");
sqlBuilder.append(dbNameResolver.getColumnName(ColumnName.LOGGER_NAME)).append(", ");
sqlBuilder.append(dbNameResolver.getColumnName(ColumnName.LEVEL_STRING)).append(", ");
sqlBuilder.append(dbNameResolver.getColumnName(ColumnName.THREAD_NAME)).append(", ");
sqlBuilder.append(dbNameResolver.getColumnName(ColumnName.REFERENCE_FLAG)).append(", ");
sqlBuilder.append(dbNameResolver.getColumnName(ColumnName.ARG0)).append(", ");
sqlBuilder.append(dbNameResolver.getColumnName(ColumnName.ARG1)).append(", ");
sqlBuilder.append(dbNameResolver.getColumnName(ColumnName.ARG2)).append(", ");
sqlBuilder.append(dbNameResolver.getColumnName(ColumnName.ARG3)).append(", ");
sqlBuilder.append(dbNameResolver.getColumnName(ColumnName.CALLER_FILENAME)).append(", ");
sqlBuilder.append(dbNameResolver.getColumnName(ColumnName.CALLER_CLASS)).append(", ");
sqlBuilder.append(dbNameResolver.getColumnName(ColumnName.CALLER_METHOD)).append(", ");
sqlBuilder.append(dbNameResolver.getColumnName(ColumnName.CALLER_LINE)).append(") ");
sqlBuilder.append("VALUES (?, ?, ? ,?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)");
return sqlBuilder.toString();
}
}
现在只需将配置中引用的DBAppender：
<appender name="DB_APPENDER" class="ch.qos.logback.classic.db.DBAppender">
更改为自己重写的类：
<appender name="DB_APPENDER" class="com.cenobitor.logging.db.LogDBAppender">
表logging_event_property、表logging_event_exception将可删除，至此基本的配置已完成，可以畅快的使用了。
三、使用
log.info(MarkerFactory.getMarker("DB"), "logback!");
即可异步将该日志输出到数据库中。