MyBatis 拦截器使用

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1. 实现接口 org.apache.ibatis.plugin.Interceptor
2. 添加注解

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

3. 重写两个普通方法

@Override
public Object plugin(Object target) {
    if (target instanceof StatementHandler) {
        return Plugin.wrap(target, this);
    } else {
        return target;
    }
}

@Override
public void setProperties(Properties properties) {
}

4. 重写重要方法

@Override
public Object intercept(Invocation invocation) throws Throwable {

    // 拦截对象
    StatementHandler statementHandler = (StatementHandler) invocation.getTarget();
    MetaObject metaObject = MetaObject.forObject(statementHandler, SystemMetaObject.DEFAULT_OBJECT_FACTORY, SystemMetaObject.DEFAULT_OBJECT_WRAPPER_FACTORY, reflectorFactory);
    MappedStatement mappedStatement = (MappedStatement) metaObject.getValue("delegate.mappedStatement");

    // 类与方法
    String id = mappedStatement.getId();
    String className = id.substring(0, id.lastIndexOf('.'));
    String methodName = id.substring(id.lastIndexOf('.') + 1);
    
    BaseStatementHandler delegate = (BaseStatementHandler) metaObject.getValue("delegate");
    BoundSql boundSql = delegate.getBoundSql();
    Object parameterObject = boundSql.getParameterObject();
    if (parameterObject instanceof MapperMethod.ParamMap) {
        MapperMethod.ParamMap paramMap = (MapperMethod.ParamMap) parameterObject;
    }

    String sql = (String) metaObject.getValue("delegate.boundSql.sql");
    metaObject.setValue("delegate.boundSql.sql", sql);

    // 传递给下一个拦截器处理
    return invocation.proceed();
}

5. 获取spring容器对象

继承 ApplicationObjectSupport
ApplicationContext applicationContext = getApplicationContext();
applicationContext.getBean(***.class);