标签：name 接口 public boundSql import Mybatis org Interceptor class

Mybatis Interceptor接口的使用

关于Mybatis中插件的声明需要在configuration的配置文件中进行配置，配置文件的位置使用configLocation属性指定。

测试中使用的config文件内容如下

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<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> <configuration>     <!--plugins插件之 分页拦截器  -->     <plugins>         <plugin interceptor="com.interceptors.LogInterceptor" ></plugin>     </plugins> </configuration>

在配置文件中配置了一个Interceptor的实现类

LogInterceptor的代码如下：

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public class LogInterceptor implements Interceptor{     @Override     public Object intercept(Invocation invocation) throws Throwable {         System.out.println("LogInterceptor : intercept");         return null;     }     @Override     public Object plugin(Object target) {         if(target instanceof StatementHandler){             RoutingStatementHandler handler = (RoutingStatementHandler)target;             //打印出当前执行的sql语句             System.out.println(handler.getBoundSql().getSql());         }         return target;     }     @Override     public void setProperties(Properties properties) {         System.out.println("LogInterceptor : setProperties");     } }

在工程的配置文件中，在配置SqlSessionFactoryBean时需要指明config配置文件的位置，配置文件如下：

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<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans"        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"        xmlns:context="http://www.springframework.org/schema/context"        xsi:schemaLocation="         http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd         http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">     <bean id="user1" class="com.beans.User">         <property name="userName" value="zhuyuqiang"/>     </bean>     <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">         <property name="name" value="mysql"/>         <property name="url" value="jdbc:mysql://127.0.0.1:3306/world"/>         <property name="username" value="root"/>         <property name="password" value="https://suowo.cn"/>         <property name="driverClassName" value="com.mysql.jdbc.Driver"/>     </bean>     <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">         <property name="dataSource" ref="dataSource"/>         <property name="mapperLocations" value="classpath:mybatis/*.xml"/>         <property name="typeAliasesPackage" value="com.entities"/>         <property name="configLocation" value="classpath:config/configuration.xml"/>     </bean>     <bean id="mapperScannerConfigurer" class="org.mybatis.spring.mapper.MapperScannerConfigurer">         <property name="basePackage" value="com.interfaces"/>     </bean>     <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">         <property name="dataSource" ref="dataSource"/>     </bean>     <context:component-scan base-package="com"/> </beans>

基本上这样配置以后，在工程中声明的plugin就已经生效了，实际中打印出来的log如下：

1	SELECT * FROM city WHERE ID=?

执行的CityMapper如下：

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<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="com.interfaces.CityMapper"> <resultMap id="BaseResultMap" type="com.entities.City">     <id column="ID" jdbcType="INTEGER" property="id"/>     <result column="Name" jdbcType="CHAR" property="name"/>     <result column="CountryCode" jdbcType="CHAR" property="countrycode"/>     <result column="District" jdbcType="CHAR" property="district"/>     <result column="Population" jdbcType="INTEGER" property="population"/> </resultMap> <select id="selectCityById" parameterType="int" resultType="com.entities.City">     SELECT * FROM city WHERE ID=#{id,jdbcType=INTEGER} </select> </mapper>

简单的测试了一下，可以打印出sql语句。在使用mybatis提供的plugin接口时需要注意，在构建ParameterHandler 、ResultSetHandler 、StatementHandler 和Executor 的时候都会调用在项目中实现的插件接口，一般情况下，如果只是为了打印显示当前执行的sql语句，可以只在当target为StatementHandler类型的时候再进行处理即可。

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public ParameterHandler newParameterHandler(MappedStatement mappedStatement, Object parameterObject, BoundSql boundSql) {   ParameterHandler parameterHandler = mappedStatement.getLang().createParameterHandler(mappedStatement, parameterObject, boundSql);   parameterHandler = (ParameterHandler) interceptorChain.pluginAll(parameterHandler);   return parameterHandler; } public ResultSetHandler newResultSetHandler(Executor executor, MappedStatement mappedStatement, RowBounds rowBounds, ParameterHandler parameterHandler,     ResultHandler resultHandler, BoundSql boundSql) {   ResultSetHandler resultSetHandler = new DefaultResultSetHandler(executor, mappedStatement, parameterHandler, resultHandler, boundSql, rowBounds);   resultSetHandler = (ResultSetHandler) interceptorChain.pluginAll(resultSetHandler);   return resultSetHandler; } public StatementHandler newStatementHandler(Executor executor, MappedStatement mappedStatement, Object parameterObject, RowBounds rowBounds, ResultHandler resultHandler, BoundSql boundSql) {     System.out.println("newStatementHandler......");     StatementHandler statementHandler = new RoutingStatementHandler(executor, mappedStatement, parameterObject, rowBounds, resultHandler, boundSql);   statementHandler = (StatementHandler) interceptorChain.pluginAll(statementHandler);   return statementHandler; } public Executor newExecutor(Transaction transaction) {   return newExecutor(transaction, defaultExecutorType); } public Executor newExecutor(Transaction transaction, ExecutorType executorType) {   executorType = executorType == null ? defaultExecutorType : executorType;   executorType = executorType == null ? ExecutorType.SIMPLE : executorType;   Executor executor;   if (ExecutorType.BATCH == executorType) {     executor = new BatchExecutor(this, transaction);   } else if (ExecutorType.REUSE == executorType) {     executor = new ReuseExecutor(this, transaction);   } else {     executor = new SimpleExecutor(this, transaction);   }   if (cacheEnabled) {     executor = new CachingExecutor(executor);   }   executor = (Executor) interceptorChain.pluginAll(executor);   return executor; }

在实际测操作中，在项目中定义实现的plugin都会被添加保存到interceptorChain对象的一个集合中，在内部会对集合里的对象进行遍历，分别调用每个插件的plugin方法。

其中target就是在调用pluginAll传入的具体对象。。。

Interceptor修改执行sql及传入参数

项目中途遇到业务需求更改，在查询某张表时需要增加条件，由于涉及的sql语句多而且依赖其他服务的jar，逐个修改sql语句和接口太繁杂。项目使用mybatis框架，因此借鉴PageHelper插件尝试使用mybatis的Interceptor来实现改需求。

总体思路

• 从BoundSql中获取sql，通过正则匹配替换表名为子查询REPLACE_TXT
• 添加子查询REPLACE_TXT 中需要用到的参数到mybatis参数列表中
• 添加参数与占位符映射，即添加ParameterMapping对象到ParameterMappings中，由于statement在执行时是按照ParameterMappings的元素索引定位占位符封装参数（即ParameterMappings中的第一个参数会封装到第一个占位符上），因此ParameterMappings中的参数顺序需要和占位符保持一致。其次ParameterMappings的元素个数需要和占位符个数保持一致。
• 为了保证该intercept在最后执行，使用AutoConfiguration将intercept添加到SqlSessionFactory的Configuration中，并在spring.factories文件中添加AutoConfiguration
• 未测试性能以及是否存在未知缺陷

1、Interceptor 代码实现

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package org.cnbi.project.other.sql.intercept; import cn.hutool.core.util.NumberUtil; import com.cnbi.cloud.common.core.exception.ServiceException; import com.github.pagehelper.Page; import com.github.pagehelper.util.ExecutorUtil; import com.github.pagehelper.util.MetaObjectUtil; import org.apache.ibatis.builder.annotation.ProviderSqlSource; import org.apache.ibatis.cache.CacheKey; 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.plugin.*; import org.apache.ibatis.reflection.MetaObject; import org.apache.ibatis.session.ResultHandler; import org.apache.ibatis.session.RowBounds; import org.cnbi.project.other.sql.aop.PeriodHolder; import java.util.*; import java.util.regex.Matcher; import java.util.regex.Pattern; /**  * @ClassName ParamInterceptor  * @Description 修改接口太繁琐，直接用mybatis拦截器对查询sql进行拦截，将期间参数注入sql  * @Author Wangjunkai  * @Date 2019/10/23 11:36  **/ @Intercepts({         @Signature(type = Executor.class, method = "query", args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class}),         @Signature(type = Executor.class, method = "query", args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class, CacheKey.class, BoundSql.class}) } ) public class ParamInterceptor implements Interceptor {     private final static Pattern DW_DIMCOMPANY = Pattern.compile("dw_dimcompany", Pattern.CASE_INSENSITIVE);     private final static String REPLACE_TXT = "(select * from dw_dimcompany where cisdel = '0' and START_PERIOD <= ? and END_PERIOD > ?)";     @Override     public Object intercept(Invocation invocation) throws Throwable {         Object[] args = invocation.getArgs();         MappedStatement ms = (MappedStatement) args[0];         Object parameter = args[1];         RowBounds rowBounds = (RowBounds) args[2];         ResultHandler resultHandler = (ResultHandler) args[3];         Executor executor = (Executor) invocation.getTarget();         CacheKey cacheKey;         BoundSql boundSql;         if(args.length == 4){             boundSql = ms.getBoundSql(parameter);         } else {             boundSql = (BoundSql) args[5];         }         //获取sql语句，使用正则忽略大小写匹配         String sql = boundSql.getSql();         Matcher matcher = DW_DIMCOMPANY.matcher(sql);         //没有需要替换的表名则放行         if(!matcher.find()){             return invocation.proceed();         }        //收集占位符个数（即paramIndex 的size）以及占位符次序（slot：即参数在ParameterMappings中的顺序）         int index = 0;         ArrayList<Integer> paramIndex = new ArrayList<>();         while(matcher.find(index)){             index = matcher.end();             String sqlPart = sql.substring(0, index);             int slot = index - sqlPart.replace("?", "").length() + paramIndex.size() ;             paramIndex.add(slot);             paramIndex.add(slot + 1);         }         //替换子查询         String companyPeriodSql = matcher.replaceAll(REPLACE_TXT);         cacheKey = args.length == 4 ? executor.createCacheKey(ms, parameter, rowBounds, boundSql) : (CacheKey) args[4];         //处理参数         Object parameterObject = processParameterObject(ms, parameter, boundSql, cacheKey, paramIndex);         BoundSql companyPeriodBoundSql = new BoundSql(ms.getConfiguration(), companyPeriodSql, boundSql.getParameterMappings(), parameterObject);         Map<String, Object> additionalParameters = ExecutorUtil.getAdditionalParameter(boundSql);         //设置动态参数         for (String key : additionalParameters.keySet()) {             companyPeriodBoundSql.setAdditionalParameter(key, additionalParameters.get(key));         }         return executor.query(ms, parameterObject, RowBounds.DEFAULT, resultHandler, cacheKey, companyPeriodBoundSql);     }     public Object processParameterObject(MappedStatement ms, Object parameterObject, BoundSql boundSql, CacheKey pageKey, ArrayList<Integer> paramIndex) {         //处理参数         Map<String, Object> paramMap = null;         if (parameterObject == null) {             paramMap = new HashMap<>();         } else if (parameterObject instanceof Map) {             //解决不可变Map的情况             paramMap = new HashMap<>();             paramMap.putAll((Map) parameterObject);         } else {             paramMap = new HashMap<>();             // sqlSource为ProviderSqlSource时，处理只有1个参数的情况             if (ms.getSqlSource() instanceof ProviderSqlSource) {                 String[] providerMethodArgumentNames = ExecutorUtil.getProviderMethodArgumentNames((ProviderSqlSource) ms.getSqlSource());                 if (providerMethodArgumentNames != null && providerMethodArgumentNames.length == 1) {                     paramMap.put(providerMethodArgumentNames[0], parameterObject);                     paramMap.put("param1", parameterObject);                 }             }             //动态sql时的判断条件不会出现在ParameterMapping中，但是必须有，所以这里需要收集所有的getter属性             //TypeHandlerRegistry可以直接处理的会作为一个直接使用的对象进行处理             boolean hasTypeHandler = ms.getConfiguration().getTypeHandlerRegistry().hasTypeHandler(parameterObject.getClass());             MetaObject metaObject = MetaObjectUtil.forObject(parameterObject);             //需要针对注解形式的MyProviderSqlSource保存原值             if (!hasTypeHandler) {                 for (String name : metaObject.getGetterNames()) {                     paramMap.put(name, metaObject.getValue(name));                 }             }             //下面这段方法，主要解决一个常见类型的参数时的问题             if (boundSql.getParameterMappings() != null && boundSql.getParameterMappings().size() > 0) {                 for (ParameterMapping parameterMapping : boundSql.getParameterMappings()) {                     String name = parameterMapping.getProperty();                     if (!name.equals(GLOBALPERIOD)                             && paramMap.get(name) == null) {                         if (hasTypeHandler                                 || parameterMapping.getJavaType().equals(parameterObject.getClass())) {                             paramMap.put(name, parameterObject);                             break;                         }                     }                 }             }         }         return processPageParameter(ms, paramMap, boundSql, pageKey, paramIndex);     }     private final static String GLOBALPERIOD = "globalPeriod";     public Object processPageParameter(MappedStatement ms, Map<String, Object> paramMap, BoundSql boundSql, CacheKey pageKey, ArrayList<Integer> paramIndex) {         paramMap.put(GLOBALPERIOD, getPeriod());         //处理pageKey         pageKey.update(getPeriod());         //处理参数配置         handleParameter(boundSql, ms, paramIndex);         return paramMap;     }     protected void handleParameter(BoundSql boundSql, MappedStatement ms,  ArrayList<Integer> paramIndex) {         if (boundSql.getParameterMappings() != null) {             List<ParameterMapping> newParameterMappings = new ArrayList<>(boundSql.getParameterMappings());             for (Integer index : paramIndex) {                 if(index < newParameterMappings.size()) {                     newParameterMappings.add(index, new ParameterMapping.Builder(ms.getConfiguration(), GLOBALPERIOD, String.class).build());                 }else{                     newParameterMappings.add(new ParameterMapping.Builder(ms.getConfiguration(), GLOBALPERIOD, String.class).build());                 }             }             MetaObject metaObject = MetaObjectUtil.forObject(boundSql);             metaObject.setValue("parameterMappings", newParameterMappings);         }     }     private final static String Q = "Q";     private final static String H = "H";     private String getPeriod(){         //使用threadlocal保存从request中获取的参数，此处不再描述         String period = PeriodHolder.getPeriod();         if(NumberUtil.isNumber(period)){             return period;         }else if(period.contains(Q)){             return period.substring(0, 4) + Integer.parseInt(period.substring(5)) * 3;         }else if(period.contains(H)){             return period.substring(0, 4) + Integer.parseInt(period.substring(5)) * 6;         }else{             throw new ServiceException("非法期间:" + period);         }     }     @Override     public Object plugin(Object target) {         return Plugin.wrap(target, this);     }     @Override     public void setProperties(Properties properties) {         //nothing to do...     } }

2、AutoConfiguration代码实现

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package org.cnbi.project.autoconfig; import com.github.pagehelper.autoconfigure.PageHelperAutoConfiguration; import org.apache.ibatis.session.SqlSessionFactory; import org.cnbi.project.other.sql.intercept.ParamInterceptor; import org.mybatis.spring.boot.autoconfigure.MybatisAutoConfiguration; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.autoconfigure.AutoConfigureAfter; import org.springframework.context.annotation.Configuration; import javax.annotation.PostConstruct; import java.util.Iterator; import java.util.List; /**  * @ClassName ParamIntecepterAutoConfiguration  * @Description  * @Author Wangjunkai  * @Date 2019/10/23 15:41  **/ @AutoConfigureAfter({MybatisAutoConfiguration.class, PageHelperAutoConfiguration.class}) @Configuration public class ParamIntecepterAutoConfiguration {     @Autowired     private List<SqlSessionFactory> sqlSessionFactoryList;     public ParamIntecepterAutoConfiguration() {     }     @PostConstruct     public void addParamInterceptor() {         ParamInterceptor interceptor = new ParamInterceptor();         Iterator var3 = this.sqlSessionFactoryList.iterator();         while(var3.hasNext()) {             SqlSessionFactory sqlSessionFactory = (SqlSessionFactory)var3.next();             sqlSessionFactory.getConfiguration().addInterceptor(interceptor);         }     } }

标签：name,接口,public,boundSql,import,Mybatis,org,Interceptor,class
来源： https://www.cnblogs.com/libaidwz/p/15324548.html

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