mybatis plugin编写

q36988

尝试使用了一下mybati的插件功能
写了一个基础类备以后使用

import java.sql.Connection;
import java.util.Properties;
import org.apache.ibatis.executor.statement.StatementHandler;
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.reflection.MetaObject;
import org.apache.ibatis.reflection.factory.DefaultObjectFactory;
import org.apache.ibatis.reflection.factory.ObjectFactory;
import org.apache.ibatis.reflection.wrapper.DefaultObjectWrapperFactory;
import org.apache.ibatis.reflection.wrapper.ObjectWrapperFactory;
import org.apache.ibatis.session.Configuration;
import org.apache.ibatis.session.RowBounds;
@Intercepts({
@Signature(type = StatementHandler.class, method = "prepare", args = { Connection.class })
})
public abstract class AbstractMyBatisPlugin implements Interceptor {
private static final ObjectFactory OBJECT_FACTORY = new DefaultObjectFactory();
private static final ObjectWrapperFactory OBJECT_WRAPPER_FACTORY = new DefaultObjectWrapperFactory();
private Properties properties;
public abstract void preIntercept(MetaObject metaStatementHandler, Configuration configuration, MappedStatement mappedStatement, BoundSql boundSql, RowBounds rowBounds);
@Override
public final Object intercept(Invocation invocation) throws Throwable {
StatementHandler statementHandler = (StatementHandler) invocation.getTarget();
MetaObject metaStatementHandler = MetaObject.forObject(statementHandler, OBJECT_FACTORY, OBJECT_WRAPPER_FACTORY);
// 分离代理对象链(由于目标类可能被多个拦截器拦截，从而形成多次代理，通过下面的两次循环可以分离出最原始的的目标类)
while (metaStatementHandler.hasGetter("h")) {
Object object = metaStatementHandler.getValue("h");
metaStatementHandler = MetaObject.forObject(object, OBJECT_FACTORY, OBJECT_WRAPPER_FACTORY);
}
// 分离最后一个代理对象的目标类
while (metaStatementHandler.hasGetter("target")) {
Object object = metaStatementHandler.getValue("target");
metaStatementHandler = MetaObject.forObject(object, OBJECT_FACTORY, OBJECT_WRAPPER_FACTORY);
}
Configuration configuration     = (Configuration) metaStatementHandler.getValue("delegate.configuration");
MappedStatement mappedStatement = (MappedStatement) metaStatementHandler.getValue("delegate.mappedStatement");
BoundSql boundSql = (BoundSql) metaStatementHandler.getValue("delegate.boundSql");
RowBounds rowBounds = (RowBounds) metaStatementHandler.getValue("delegate.rowBounds");
preIntercept(metaStatementHandler, configuration, mappedStatement, boundSql, rowBounds);
return invocation.proceed();
}
@Override
public final Object plugin(Object target) {
if (target instanceof StatementHandler) {
return Plugin.wrap(target, this);
} else {
return target;
}
}
public Properties getProperties() {
return properties;
}
@Override
public void setProperties(Properties properties) {
this.properties = properties;
}
}