使用MyBatis/MyBatis Plus实现SQL日志打印与执行监控
一、背景与价值
在开发过程中，SQL日志的完整输出对于调试和性能优化至关重要。MyBatis默认的日志输出仅显示带占位符的SQL语句，无法直接看到实际参数值，且缺乏执行时间统计。本文将介绍两种实现方案：
- 原生配置方案：通过日志框架直接输出基础SQL日志
- 增强方案：使用MyBatis拦截器实现完整SQL打印和执行监控
二、原生配置方案（快速上手）
1. 日志框架配置（以Logback为例）
xml
<!-- logback-spring.xml -->
<configuration>
<logger name="com.zaxxer.hikari" level="INFO"/>
<logger name="java.sql.Connection" level="INFO"/>
<logger name="java.sql.Statement" level="DEBUG"/>
<logger name="java.sql.PreparedStatement" level="DEBUG"/>
</configuration>2. 输出示例
java
DEBUG [main] - ==> Preparing: SELECT * FROM user WHERE name = ?
DEBUG [main] - ==> Parameters: John(String)3. 局限性
- 参数值单独显示，无法直接拼接完整SQL
- 缺乏执行耗时统计
- 动态SQL处理不够直观
三、增强方案：自定义拦截器实现
1. SQL美化与参数替换
java
public class MybatisPlusAllSqlLog implements InnerInterceptor {
public static final Logger log = LoggerFactory.getLogger("sys-sql");
@Override
public void beforeQuery(Executor executor, MappedStatement ms, Object parameter, RowBounds rowBounds, ResultHandler resultHandler, BoundSql boundSql) throws SQLException {
logInfo(boundSql, ms, parameter);
}
@Override
public void beforeUpdate(Executor executor, MappedStatement ms, Object parameter) throws SQLException {
BoundSql boundSql = ms.getBoundSql(parameter);
logInfo(boundSql, ms, parameter);
}
private static void logInfo(BoundSql boundSql, MappedStatement ms, Object parameter) {
try {
log.info("parameter = " + parameter);
// 获取到节点的id,即sql语句的id
String sqlId = ms.getId();
log.info("sqlId = " + sqlId);
// 获取节点的配置
Configuration configuration = ms.getConfiguration();
// 获取到最终的sql语句
String sql = getSql(configuration, boundSql, sqlId);
log.info("完整的sql:{}", sql);
} catch (Exception e) {
log.error("异常:{}", e.getLocalizedMessage(), e);
}
}
// 封装了一下sql语句，使得结果返回完整xml路径下的sql语句节点id + sql语句
public static String getSql(Configuration configuration, BoundSql boundSql, String sqlId) {
return sqlId + ":" + showSql(configuration, boundSql);
}
// 进行？的替换
public static String showSql(Configuration configuration, BoundSql boundSql) {
// 获取参数
Object parameterObject = boundSql.getParameterObject();
List<ParameterMapping> parameterMappings = boundSql.getParameterMappings();
// sql语句中多个空格都用一个空格代替
String sql = boundSql.getSql().replaceAll("[\\s]+", " ");
if (!CollectionUtils.isEmpty(parameterMappings) && parameterObject != null) {
// 获取类型处理器注册器，类型处理器的功能是进行java类型和数据库类型的转换
TypeHandlerRegistry typeHandlerRegistry = configuration.getTypeHandlerRegistry();
// 如果根据parameterObject.getClass(）可以找到对应的类型，则替换
if (typeHandlerRegistry.hasTypeHandler(parameterObject.getClass())) {
sql = sql.replaceFirst("\\?",
Matcher.quoteReplacement(getParameterValue(parameterObject)));
} else {
// MetaObject主要是封装了originalObject对象，提供了get和set的方法用于获取和设置originalObject的属性值,主要支持对JavaBean、Collection、Map三种类型对象的操作
MetaObject metaObject = configuration.newMetaObject(parameterObject);
for (ParameterMapping parameterMapping : parameterMappings) {
String propertyName = parameterMapping.getProperty();
if (metaObject.hasGetter(propertyName)) {
Object obj = metaObject.getValue(propertyName);
sql = sql.replaceFirst("\\?",
Matcher.quoteReplacement(getParameterValue(obj)));
} else if (boundSql.hasAdditionalParameter(propertyName)) {
// 该分支是动态sql
Object obj = boundSql.getAdditionalParameter(propertyName);
sql = sql.replaceFirst("\\?",
Matcher.quoteReplacement(getParameterValue(obj)));
} else {
// 打印出缺失，提醒该参数缺失并防止错位
sql = sql.replaceFirst("\\?", "缺失");
}
}
}
}
return sql;
}
// 如果参数是String，则添加单引号， 如果是日期，则转换为时间格式器并加单引号； 对参数是null和不是null的情况作了处理
private static String getParameterValue(Object obj) {
String value;
if (obj instanceof String) {
value = "'" + obj.toString() + "'";
} else if (obj instanceof Date) {
DateFormat formatter = DateFormat.getDateTimeInstance(DateFormat.DEFAULT,
DateFormat.DEFAULT, Locale.CHINA);
value = "'" + formatter.format(new Date()) + "'";
} else {
if (obj != null) {
value = obj.toString();
} else {
value = "";
}
}
return value;
}
}2. 执行耗时监控
java
@Intercepts({
@Signature(type = Executor.class, method = "update", args = {MappedStatement.class,
Object.class}),
@Signature(type = Executor.class, method = "query", args = {MappedStatement.class,
Object.class, RowBounds.class, ResultHandler.class, CacheKey.class, BoundSql.class})})
public class SqlStatementInterceptor implements Interceptor {
public static final Logger log = LoggerFactory.getLogger("sys-sql");
@Override
public Object intercept(Invocation invocation) throws Throwable {
long startTime = System.currentTimeMillis();
try {
return invocation.proceed();
} finally {
long timeConsuming = System.currentTimeMillis() - startTime;
log.info("执行SQL:{}ms", timeConsuming);
if (timeConsuming > 999 && timeConsuming < 5000) {
log.info("执行SQL大于1s:{}ms", timeConsuming);
} else if (timeConsuming >= 5000 && timeConsuming < 10000) {
log.info("执行SQL大于5s:{}ms", timeConsuming);
} else if (timeConsuming >= 10000) {
log.info("执行SQL大于10s:{}ms", timeConsuming);
}
}
}
@Override
public Object plugin(Object target) {
return Plugin.wrap(target, this);
}
@Override
public void setProperties(Properties properties) {
}
}自定义拦截器之后，请注意配置该拦截器
3.输出示例
java
INFO [http-nio-8080-exec-1] - SQLID: com.example.mapper.UserMapper.selectById
INFO [http-nio-8080-exec-1] - 完整SQL: SELECT id,name,age FROM user WHERE id=1
INFO [http-nio-8080-exec-1] - 执行耗时: 48ms
WARN [http-nio-8080-exec-1] - 慢SQL警告: 执行耗时1204ms四.总结
通过合理配置SQL日志输出，开发者可以：
- 快速定位SQL执行问题
- 直观分析实际执行的SQL语句
- 有效识别性能瓶颈
- 提升动态SQL调试效率