spring boot Mybatis 拦截器实现拼接sql和修改的代码详解

import com.culturalCenter.placeManage.globalConfig.Interface.InterceptAnnotation;

import org.apache.ibatis.executor.statement.StatementHandler;

import org.apache.ibatis.mapping.BoundSql;

import org.apache.ibatis.mapping.MappedStatement;

import org.apache.ibatis.plugin.*;

import org.apache.ibatis.reflection.DefaultReflectorFactory;

import org.apache.ibatis.reflection.MetaObject;

import org.apache.ibatis.reflection.SystemMetaObject;

import org.apache.ibatis.session.ResultHandler;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

import org.springframework.context.annotation.Configuration;

import org.springframework.stereotype.Component;

import java.lang.reflect.Field;

import java.lang.reflect.Method;

import java.sql.Statement;

import java.util.Properties;

@Intercepts ({ @Signature (type = StatementHandler. class , method = "query" , args = {Statement. class , ResultHandler. class }),

         @Signature (type = StatementHandler. class , method = "update" , args = {Statement. class }),

         @Signature (type = StatementHandler. class , method = "batch" , args = {Statement. class })})

@Component

@Configuration

public class SqlInterceptor implements Interceptor {

     private Logger logger = LoggerFactory.getLogger(SqlInterceptor. class );

     @Override

     public Object intercept(Invocation invocation) throws Throwable {

         StatementHandler statementHandler = (StatementHandler) invocation.getTarget();

         MetaObject metaObject = MetaObject.forObject(statementHandler, SystemMetaObject.DEFAULT_OBJECT_FACTORY, SystemMetaObject.DEFAULT_OBJECT_WRAPPER_FACTORY, new DefaultReflectorFactory());

         //先拦截到RoutingStatementHandler，里面有个StatementHandler类型的delegate变量，其实现类是BaseStatementHandler，然后就到BaseStatementHandler的成员变量mappedStatement

         MappedStatement mappedStatement = (MappedStatement) metaObject.getValue( "delegate.mappedStatement" );

         //id为执行的mapper方法的全路径名，如com.uv.dao.UserMapper.insertUser

         String id = mappedStatement.getId();

         logger.info( "拦截到当前请求方法的全路径名为--->:  " + id);

         //sql语句类型 select、delete、insert、update

         String sqlCommandType = mappedStatement.getSqlCommandType().toString();

         BoundSql boundSql = statementHandler.getBoundSql();

         //获取到原始sql语句

         String sql = boundSql.getSql();

         String mSql = sql;

         //获取参数

         Object parameter = statementHandler.getParameterHandler().getParameterObject();

         logger.info( "拦截到当前请求SQL为--->: " + sql + "<------------>请求类型为:  " + sqlCommandType);

         logger.info( "拦截到当前请求参数为--->: " + parameter);

         //TODO 修改位置

         //注解逻辑判断  添加注解了才拦截//InterceptAnnotation

         Class<?> classType = Class.forName(mappedStatement.getId().substring( 0 , mappedStatement.getId().lastIndexOf( "." )));

         String mName = mappedStatement.getId().substring(mappedStatement.getId().lastIndexOf( "." ) + 1 , mappedStatement.getId().length());

         for (Method method : classType.getDeclaredMethods()) {

             if (method.isAnnotationPresent(InterceptAnnotation. class ) && mName.equals(method.getName())) {

                 InterceptAnnotation interceptorAnnotation = method.getAnnotation(InterceptAnnotation. class );

                 if (interceptorAnnotation.flag()) {

                     mSql = sql + " limit 2" ;

                 }

             }

         }

         //通过反射修改sql语句

         Field field = boundSql.getClass().getDeclaredField( "sql" );

         field.setAccessible( true );

         field.set(boundSql, mSql);

         return invocation.proceed();

     }

     @Override

     public Object plugin(Object target) {

         return Plugin.wrap(target, new SqlInterceptor());

     }

     @Override

     public void setProperties(Properties properties) {

//        this.setProperties(properties);

     }

import java.lang.annotation.ElementType;

import java.lang.annotation.Retention;

import java.lang.annotation.RetentionPolicy;

import java.lang.annotation.Target;

/**

  * 配合SqlInterceptor实现局部拦截

  * */

@Target ({ElementType.METHOD,ElementType.PARAMETER})

@Retention (RetentionPolicy.RUNTIME)

public @interface InterceptAnnotation {

     boolean flag() default   true ;

}

package com.culturalCenter.placeManage.globalConfig;

import com.alibaba.druid.pool.DruidDataSource;

import org.apache.ibatis.plugin.Interceptor;

import org.apache.ibatis.session.SqlSessionFactory;

import org.mybatis.spring.SqlSessionFactoryBean;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.Configuration;

import org.springframework.context.annotation.Primary;

import org.springframework.core.io.Resource;

import org.springframework.core.io.support.PathMatchingResourcePatternResolver;

import javax.sql.DataSource;

/**

  * @author wulincheng

  * @Date 2020年6月23日18:25:22

  *  创建SQL连接工厂类

  * */

@Configuration

public class SqlSessionFactoryConfig {

     @javax .annotation.Resource

     DruidDataSource dataSource;

     /**

      * @Autowired SqlSessionFactory sqlSessionFactory;

      * SqlSession session = sqlSessionFactory.openSession();

      * //创建sqlMapper

      * SqlMapper sqlMapper = new SqlMapper(session);

      */

     @Bean

     @Primary

     public SqlSessionFactory sqlSessionFactory() throws Exception {

         SqlSessionFactoryBean bean = new SqlSessionFactoryBean();

         bean.setDataSource(dataSource); //更多参数请自行注入

         bean.setPlugins( new Interceptor[]{ new SqlInterceptor()});

         Resource[] resources = new PathMatchingResourcePatternResolver()

                 .getResources( "classpath*:mapper/*.xml" );

         bean.setMapperLocations(resources);

         return bean.getObject();

     }

}