拦截器介绍

mybatis提供了@Intercepts注解允许开发者对mybatis的执行器Executor进行拦截。

Executor接口方法主要有update、query、commit、rollback等等。

主要思路为:

进入拦截器方法中
获取拦截器方法参数
获取解析参数及SQL
自定义生成自己的SQL语句
将自定义SQL设置进参数中
由mybatis处理后续问题

拦截器代码

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.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.springframework.stereotype.Component;

import java.lang.reflect.Field;

import java.lang.reflect.Modifier;

import java.util.Properties;

@Component

@Intercepts({@org.apache.ibatis.plugin.Signature(type = Executor.class, method = "query",

        args = {

        MappedStatement.class,

                Object.class,

                RowBounds.class,

                ResultHandler.class,

                CacheKey.class,

                BoundSql.class})})

public class MybatisInterceptorConfig implements Interceptor {

	 /*自定义SQL*/

	 private String resetSql(String sql) {

     }

    @Override

    public Object intercept(Invocation invocation) throws Throwable {

        resetSql(invocation);

        return invocation.proceed();

    }

    @Override

    public Object plugin(Object o) {

        return Plugin.wrap(o, this);

    }

    @Override

    public void setProperties(Properties properties) {

	}

    private void resetSql(Invocation invocation) {

        final Object[] args = invocation.getArgs();

        BoundSql boundSql = (BoundSql) args[5];

		if(StringUtils.isNotEmpty(boundSql.getSql())) {

			modify(boundSql,"sql",resetSql(boundSql.getSql()));

		}

    }

    private static void modify(Object object, String fieldName, Object newFieldValue){

        try {

            Field field = object.getClass().getDeclaredField(fieldName);

            Field modifiersField = Field.class.getDeclaredField("modifiers");

            modifiersField.setAccessible(true);

            modifiersField.setInt(field, field.getModifiers() & ~Modifier.FINAL);

            if(!field.isAccessible()) {

                field.setAccessible(true);

            }

            field.set(object, newFieldValue);

        } catch (Exception e) {

            e.printStackTrace();

        }

    }

}

巴特西

mybatis - 基于拦截器修改执行中的SQL语句

拦截器介绍

拦截器代码

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