eclipse运行不了the constructor Selection does not contain a main type
时间: 2024-05-02 21:16:18 浏览: 11
这个错误通常是因为你的代码中并没有包含名为`main`的方法,或者`main`方法的格式不正确。
`main`方法必须是一个公共(public)的静态(static)方法,返回值类型必须为`void`,方法名必须为`main`,并且接受一个字符串数组作为参数。
如果你已经有一个名为`main`的方法,那么请检查一下它的格式是否正确。如果还没有`main`方法,那么你需要添加一个`main`方法,例如:
```java
public class Selection {
public static void main(String[] args) {
// 在这里编写你的代码
}
}
```
这将创建一个名为`Selection`的类,并在其中定义了一个名为`main`的方法。你可以在这个方法中编写你的程序代码。
相关问题
报错:MyThread::MyThread names a constructor ,not the type
这个错误通常是因为在定义类时,类名和构造函数名相同导致的。请检查你的代码,确保类名和构造函数名不同。
示例代码:
```
class MyThread {
public:
MyThread() {
// constructor code here
}
};
```
在这个例子中,MyThread 类的构造函数是 MyThread(),而不是类名。如果你的代码中类名和构造函数名相同,需要将构造函数的名称改为与类名不同的名称。
org.apache.spark.SparkContext does not have a constructor
This error message usually occurs when you are trying to create an instance of the SparkContext class in Apache Spark but you are using a constructor that is not defined for that class.
The SparkContext class in Apache Spark has several constructors that are used to create an instance of the SparkContext object. You need to make sure that you are using the correct constructor and providing the required parameters.
Here's an example of how to create a SparkContext object using the default constructor:
```
import org.apache.spark.{SparkConf, SparkContext}
val conf = new SparkConf().setAppName("MyApp").setMaster("local")
val sc = new SparkContext(conf)
```
In this example, we are creating a SparkConf object and setting the application name and master URL. Then, we are using the SparkContext constructor that takes a SparkConf object as a parameter.
You can also create a SparkContext object using other constructors that take different parameters, such as the SparkConf object and the name of the Spark application.
Make sure that you are using the correct constructor and providing all the required parameters to create an instance of the SparkContext class in Apache Spark.