Mybatis中的插件允许你针对核心组件接口Executor 、StatementHandler、ParameterHandler、ResultSetHandler中任何一个方法进行拦截调用。而每个Interceptor(拦截的接口)其实是通过JDK的动态代理技术生成的代理类,每当执行这4种接口中的方法时,就会进入拦截方法(具体就是InvocationHandler的invoke()方法)。
所以我们要做的就是实现 Interceptor 接口,并指定想要拦截的方法签名。如下示例,拦截的是query和update方法。
/*
* MyBatis 将mybatis要执行的sql拦截打印出来
*/
@Intercepts
({
@Signature(type = Executor.class, method = "query", args = {MappedStatement.class, Object.class,
RowBounds.class, ResultHandler.class}),
@Signature(type = Executor.class, method = "update", args = {MappedStatement.class, Object.class})
})
public class SqlPrintInterceptor implements Interceptor {
关键是要打印出完整的带参数的SQL。
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
import java.util.Properties;
import java.util.regex.Matcher;
import org.apache.ibatis.executor.Executor;
import org.apache.ibatis.mapping.BoundSql;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.ParameterMapping;
import org.apache.ibatis.mapping.ParameterMode;
import org.apache.ibatis.plugin.Interceptor;
import org.apache.ibatis.plugin.Intercepts;
import org.apache.ibatis.plugin.Invocation;
import org.apache.ibatis.plugin.Plugin;
import org.apache.ibatis.plugin.Signature;
import org.apache.ibatis.reflection.MetaObject;
import org.apache.ibatis.session.Configuration;
import org.apache.ibatis.session.ResultHandler;
import org.apache.ibatis.session.RowBounds;
import org.apache.ibatis.type.TypeHandlerRegistry;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/*
* MyBatis 将mybatis要执行的sql拦截打印出来
*/
@Intercepts
({
@Signature(type = Executor.class, method = "query", args = {MappedStatement.class, Object.class,
RowBounds.class, ResultHandler.class}),
@Signature(type = Executor.class, method = "update", args = {MappedStatement.class, Object.class})
})
public class SqlPrintInterceptor implements Interceptor {
private static final Logger log = LoggerFactory.getLogger(SqlPrintInterceptor.class);
private static final DateFormat DATE_FORMAT = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
@Override
public Object intercept(Invocation invocation) throws Throwable {
MappedStatement mappedStatement = (MappedStatement) invocation.getArgs()[0];
Object parameterObject = null;
if (invocation.getArgs().length > 1) {
parameterObject = invocation.getArgs()[1];
}
long start = System.currentTimeMillis();
Object result = invocation.proceed();
String statementId = mappedStatement.getId();
BoundSql boundSql = mappedStatement.getBoundSql(parameterObject);
Configuration configuration = mappedStatement.getConfiguration();
String sql = getSql(boundSql, parameterObject, configuration);
long end = System.currentTimeMillis();
long timing = end - start;
//根据个人喜好看需要打印怎么sql,本人是打印打印 1s的
if (log.isInfoEnabled() && timing > 1000) {
log.info("execl sql spend time:{} ms. dao methods id:{},execl sql is: {}", timing, statementId, sql);
}
return result;
}
@Override
public Object plugin(Object target) {
if (target instanceof Executor) {
return Plugin.wrap(target, this);
}
return target;
}
@Override
public void setProperties(Properties properties) {
}
private String getSql(BoundSql boundSql, Object parameterObject, Configuration configuration) {
String sql = boundSql.getSql().replaceAll("[\\s]+", " ");
List<ParameterMapping> parameterMappings = boundSql.getParameterMappings();
TypeHandlerRegistry typeHandlerRegistry = configuration.getTypeHandlerRegistry();
if (parameterMappings != null) {
for (int i = 0; i < parameterMappings.size(); i++) {
ParameterMapping parameterMapping = parameterMappings.get(i);
if (parameterMapping.getMode() != ParameterMode.OUT) {
Object value;
String propertyName = parameterMapping.getProperty();
if (boundSql.hasAdditionalParameter(propertyName)) {
value = boundSql.getAdditionalParameter(propertyName);
} else if (parameterObject == null) {
value = null;
} else if (typeHandlerRegistry.hasTypeHandler(parameterObject.getClass())) {
value = parameterObject;
} else {
MetaObject metaObject = configuration.newMetaObject(parameterObject);
value = metaObject.getValue(propertyName);
}
sql = replacePlaceholder(sql, value);
}
}
}
return sql;
}
private String replacePlaceholder(String sql, Object propertyValue) {
String result;
if (propertyValue != null) {
if (propertyValue instanceof String) {
result = "'" + propertyValue + "'";
} else if (propertyValue instanceof Date) {
result = "'" + DATE_FORMAT.format(propertyValue) + "'";
} else {
result = propertyValue.toString();
}
} else {
result = "null";
}
return sql.replaceFirst("\\?", Matcher.quoteReplacement(result));
}
}