mybatis @Intercepts的用法解读

package com.testmybatis.interceptor;

import java.util.Properties;

import org.apache.ibatis.executor.Executor;

import org.apache.ibatis.mapping.BoundSql;

import org.apache.ibatis.mapping.MappedStatement;

import org.apache.ibatis.mapping.SqlSource;

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.session.ResultHandler;

import org.apache.ibatis.session.RowBounds;

import org.apache.log4j.Logger;

@Intercepts ({ @org .apache.ibatis.plugin.Signature(type = Executor. class , method = "query" , args = {MappedStatement. class , Object. class , RowBounds. class , ResultHandler. class }) })

public class SqlInterceptor implements Interceptor {

     private Logger log=Logger.getLogger(getClass());

     public Object intercept(Invocation invocation) throws Throwable {

         // TODO Auto-generated method stub

         log.info( "Interceptor......" );

         // 获取原始sql语句

         MappedStatement mappedStatement = (MappedStatement) invocation.getArgs()[ 0 ];

         Object parameter = invocation.getArgs()[ 1 ];

         BoundSql boundSql = mappedStatement.getBoundSql(parameter);

         String oldsql = boundSql.getSql();

         log.info( "old:" +oldsql);

         // 改变sql语句

         BoundSql newBoundSql = new BoundSql(mappedStatement.getConfiguration(), oldsql + " where id=1" ,

                 boundSql.getParameterMappings(), boundSql.getParameterObject());

         MappedStatement newMs = copyFromMappedStatement(mappedStatement, new BoundSqlSqlSource(newBoundSql));

         invocation.getArgs()[ 0 ] = newMs;

         // 继续执行

         Object result = invocation.proceed();

         return result;

     }

     public Object plugin(Object target) {

         // TODO Auto-generated method stub

         return Plugin.wrap(target, this );

     }

     public void setProperties(Properties properties) {

         // TODO Auto-generated method stub

     }

     // 复制原始MappedStatement

     private MappedStatement copyFromMappedStatement(MappedStatement ms, SqlSource newSqlSource) {

         MappedStatement.Builder builder = new MappedStatement.Builder(ms.getConfiguration(), ms.getId(), newSqlSource,

                 ms.getSqlCommandType());

         builder.resource(ms.getResource());

         builder.fetchSize(ms.getFetchSize());

         builder.statementType(ms.getStatementType());

         builder.keyGenerator(ms.getKeyGenerator());

         if (ms.getKeyProperties() != null ) {

             for (String keyProperty : ms.getKeyProperties()) {

                 builder.keyProperty(keyProperty);

             }

         }

         builder.timeout(ms.getTimeout());

         builder.parameterMap(ms.getParameterMap());

         builder.resultMaps(ms.getResultMaps());

         builder.cache(ms.getCache());

         builder.useCache(ms.isUseCache());

         return builder.build();

     }

     public static class BoundSqlSqlSource implements SqlSource {

         BoundSql boundSql;

         public BoundSqlSqlSource(BoundSql boundSql) {

             this .boundSql = boundSql;

         }

         public BoundSql getBoundSql(Object parameterObject) {

             return boundSql;

         }

     }

}

<? 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 >

         < plugin interceptor = "com.testmybatis.interceptor.SqlInterceptor" />

     </ plugins >

     < environments default = "development" >

         < environment id = "development" >

             < transactionManager type = "JDBC" />

             < dataSource type = "POOLED" >

                 < property name = "driver" value = "com.mysql.cj.jdbc.Driver" />

                 < property name = "url"

                     value = "jdbc:mysql://127.0.0.1:3306/test?serverTimezone=UTC&amp;useUnicode=true&amp;characterEncoding=utf-8&amp;useSSL=true" />

                 < property name = "username" value = "root" />

                 < property name = "password" value = "123456" />

             </ dataSource >

         </ environment >

     </ environments >

     < mappers >

         < mapper resource = "com/testmybatis/dao/TestMapper.xml" />

     </ mappers >   

</ configuration >

package com.testmybatis.model;

import java.io.Serializable;

public class Test implements Serializable{

     /**

      *

      */

     private static final long serialVersionUID = 1L;

     private int id;

     private String name;

     public int getId() {

         return id;

     }

     public void setId( int id) {

         this .id = id;

     }

     public String getName() {

         return name;

     }

     public void setName(String name) {

         this .name = name;

     }

     public String toString(){

         return "id:" +id+ " name:" +name;

     }

}

package com.testmybatis.dao;

import java.util.List;

import org.apache.ibatis.annotations.Select;

import com.testmybatis.model.Test; 

public interface TestMapper {

     public List<Test> test();

}

<? 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.testmybatis.dao.TestMapper" >

     < select id = "test" resultType = "com.testmybatis.model.Test" >

         select * from test

     </ select >

</ mapper >

try {

         String resource = "com/testmybatis/mybatis-config.xml" ;

         InputStream inputStream = Resources.getResourceAsStream(resource);

         SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

         SqlSession session = sqlSessionFactory.openSession();

         try {

             TestMapper mapper=session.getMapper(TestMapper. class );

             List<Test> tests=mapper.test();

             session测试数据mit();

             log.info(JSON.toJSONString(tests));

         } finally {

             session.close();

         }

     } catch (IOException e) {

         // TODO Auto-generated catch block

         e.printStackTrace();

     }

package com.tiantian.mybatis.interceptor;

import java.sql.Connection;

import java.util.Properties;

import org.apache.ibatis.executor.Executor;

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

import org.apache.ibatis.mapping.MappedStatement;

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.session.ResultHandler;

import org.apache.ibatis.session.RowBounds;

@Intercepts ( {

     @Signature (method = "query" , type = Executor. class , args = {

            MappedStatement. class , Object. class , RowBounds. class ,

            ResultHandler. class }),

     @Signature (method = "prepare" , type = StatementHandler. class , args = { Connection. class }) })

public class MyInterceptor implements Interceptor {

     @Override

     public Object intercept(Invocation invocation) throws Throwable {

         Object result = invocation.proceed();

         System.out.println( "Invocation.proceed()" );

         return result;

     }

     @Override

     public Object plugin(Object target) {

         // TODO Auto-generated method stub

         return Plugin.wrap(target, this );

     }

     @Override

     public void setProperties(Properties properties) {

         String prop1 = properties.getProperty( "prop1" );

         String prop2 = properties.getProperty( "prop2" );

         System.out.println(prop1 + "------" + prop2);

     }

}

<? 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 >

     < properties resource = "jdbc.properties" ></ properties >

     < typeAliases >

        < package name = "com.tiantian.mybatis.model" />

     </ typeAliases >

     < plugins >

        < plugin interceptor = "com.tiantian.mybatis.interceptor.MyInterceptor" >

            < property name = "prop1" value = "prop1" />

            < property name = "prop2" value = "prop2" />

        </ plugin >

     </ plugins >

     < environments default = "development" >

        < environment id = "development" >

            < transactionManager type = "JDBC" />

            < dataSource type = "POOLED" >

               < property name = "driver" value = "${driver}" />

               < property name = "url" value = "${url}" />

               < property name = "username" value = "${username}" />

               < property name = "password" value = "${password}" />

            </ dataSource >

        </ environment >

     </ environments >

     < mappers >

        < mapper resource = "com/tiantian/mybatis/mapper/UserMapper.xml" />

     </ mappers >

</ configuration >

driver=com.mysql.jdbc.Driver

url=jdbc:mysql://localhost:3306/database_yxl

username=root

password =123456

#定义初始连接数

initialSize=0

#定义最大连接数

maxActive=20

#定义最大空闲

maxIdle=20

#定义最小空闲

minIdle=1

#定义最长等待时间

maxWait=60000

package com.tiantian.mybatis.service;

import org.apache.ibatis.session.SqlSession;

import com.tiantian.base.MyBatisUtil;

import com.tiantian.mybatis.domain.User;

public class TestMyBatis {

     public static void main(String[] args) {

         SqlSession session = MyBatisUtil.getSqlSession();

         /**

          * 映射sql的标识字符串，

          * com.tiantian.mybatis.mapper.userMapper是userMapper.xml文件中mapper标签的namespace属性的值，

          * selectByPrimaryKey是select标签的id属性值，通过select标签的id属性值就可以找到要执行的SQL

          */

         String statement = "com.tiantian.mybatis.mapper.UserMapper.selectByPrimaryKey" ; //映射sql的标识字符串

         //执行查询返回一个唯一user对象的sql

         User user = session.selectOne(statement, 1 );

         System.out.println(user);

     }

}

package com.tiantian.base;

import java.io.InputStream;

import org.apache.ibatis.session.SqlSession;

import org.apache.ibatis.session.SqlSessionFactory;

import org.apache.ibatis.session.SqlSessionFactoryBuilder;

public class MyBatisUtil {

     public static SqlSessionFactory getSqlSessionFactory() {

         String resource = "mybatis-config.xml" ;

         // 使用类加载器加载mybatis的配置文件（它也加载关联的映射文件）

         InputStream is = MyBatisUtil. class .getClassLoader().getResourceAsStream(resource);

         // 构建sqlSession的工厂

         SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(is);

         return sessionFactory;

     }

     public static SqlSession getSqlSession() {

         return getSqlSessionFactory().openSession();

     }

     public static SqlSession getSqlSession( boolean isAutoCommit) {

         return getSqlSessionFactory().openSession(isAutoCommit);

     }

}