How can we dynamically add fields to MyBatis interceptors?

2 years ago
Olivia Parker
1 minute

MyBatis interceptors are tools used to process parameters or results before or after executing SQL statements. To dynamically add fields, you can follow the steps below:

  1. The person or thing that intercepts.
  2. capture the signal
  3. extension
public class MyInterceptor implements Interceptor {
    @Override
    public Object intercept(Invocation invocation) throws Throwable {
        // 在此处进行字段的动态添加
        // ...
        return invocation.proceed();
    }

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

    @Override
    public void setProperties(Properties properties) {
        // 可以在此处设置一些属性
    }
}
  1. Settings or options for setup
<plugins>
    <plugin interceptor="com.example.MyInterceptor">
        <!-- 设置一些属性 -->
    </plugin>
</plugins>
  1. catch or stop something before it reaches its intended destination
  2. calling upon a higher power
  3. An object that provides metadata
@Override
public Object intercept(Invocation invocation) throws Throwable {
    // 获取方法参数
    Object[] args = invocation.getArgs();
    // 获取SQL语句的元数据
    MappedStatement ms = (MappedStatement) args[0];
    // 获取SQL语句的类型
    SqlCommandType commandType = ms.getSqlCommandType();
    
    if (commandType == SqlCommandType.INSERT || commandType == SqlCommandType.UPDATE) {
        // 获取参数对象
        Object parameter = args[1];
        if (parameter != null) {
            // 使用MetaObject对参数对象进行封装
            MetaObject metaObject = SystemMetaObject.forObject(parameter);
            // 动态添加字段
            metaObject.setValue("fieldName", value);
        }
    }

    return invocation.proceed();
}

Note: The above code is just an example, adjustments should be made according to specific business requirements when actually used.

bannerAds