mybatis Executor插件加载源码

//插件扩展实现类：

org.apache.ibatis.session.Configuration

//具体方法：

protected ExecutorType defaultExecutorType = ExecutorType.SIMPLE;  

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;
  }

    Executor接口：

public interface Executor {

  ResultHandler NO_RESULT_HANDLER = null;

  int update(MappedStatement ms, Object parameter) throws SQLException;

  List query(MappedStatement ms, Object parameter, RowBounds rowBounds, ResultHandler resultHandler) throws SQLException;

  List<BatchResult> flushStatements() throws SQLException;

  void commit(boolean required) throws SQLException;

  void rollback(boolean required) throws SQLException;

  CacheKey createCacheKey(MappedStatement ms, Object parameterObject, RowBounds rowBounds);

  boolean isCached(MappedStatement ms, CacheKey key);

  void clearLocalCache();

  void deferLoad(MappedStatement ms, MetaObject resultObject, String property, CacheKey key);

  Transaction getTransaction();

  void close(boolean forceRollback);
  
  boolean isClosed();

}

 

 

插件继承和扩展：

implements Interceptor

  

   

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

 

 

具体实例：

package com.xuanwu.sms.smstask.webmanager.common.crud.plugins;

import java.lang.reflect.Field;
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.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(type = Executor.class, method = "query", args = {
		MappedStatement.class, Object.class, RowBounds.class,
		ResultHandler.class }) })
public class PaginationInterceptor implements Interceptor {

	public Object intercept(Invocation invocation) throws Throwable {

		MappedStatement mappedStatement = (MappedStatement) invocation.getArgs()[0];
		Object parameter = invocation.getArgs()[1];
		mappedStatement.getSqlSource().getBoundSql(parameter);
		BoundSql boundSql = mappedStatement.getBoundSql(parameter);

		if (boundSql == null || boundSql.getSql() == null || "".equals(boundSql.getSql())) {
			return null;
		}
		
		String newSql = "select * from (" + boundSql.getSql() + ") t";
		
		Class<?> cla =boundSql.getClass();
		Field field = cla.getDeclaredField("sql");
		field.setAccessible(true);
		field.set(boundSql, newSql);
		String test = boundSql.getSql();
		
		return invocation.proceed();
	}

	public Object plugin(Object target) {
		return Plugin.wrap(target, this);
	}

	public void setProperties(Properties properties) {
		String dialectClass = properties.getProperty("dialectClass");
		try {
			Object dialect = (Object) Class.forName(dialectClass).newInstance();
		} catch (InstantiationException e) {
			e.printStackTrace();
		} catch (IllegalAccessException e) {
			e.printStackTrace();
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}

	}

}