Write an SSH automatic login script with Shebang

Singleton mode is a very common mode in software development. Its primary function is to ensure that only one instance object of a class is always present in the system.

The benefits of doing this are two points:

1. For objects that require frequent use, each time they are used, they need to be recreated and the contents of these objects are the same. Not only improves the performance overhead of the JVM (opening new addresses in the heap while reducing GC efficiency), but also reduces the efficiency of the Code. If there is always only one instance object in the heap. When any method is used, the object is accessed directly, which greatly improves the operation efficiency of the system.

How do I tell if scrollbars scroll to the bottom of the page? We can set a rule: when the scroll height of the scroll bar is less than 20 pixels from the height of the entire document,

The whole project team tried various ways to solve, still no role, and finally everyone said: "Or we will change back to the old version, in the most primitive way across the domain?" I said, you guys let me try it again ... This period, to find the company's technology Daniel also to help me solve this problem, wasted his old half time still can't find the reason, thank him for wasting time with me toss.

Object-oriented thinking is already very mature, and programmers using C # are very familiar with object-oriented, so I'm not going to introduce object-oriented, and in this article we'll just cover the use of object-oriented in F #.

Do you feel depressed when you see such a headline? Do you have implementation code in the interface? How is that possible? It is true that an interface can declare constants, declare abstract methods, and inherit the parent interface, but there is no specific implementation, because an interface is a contract (contract), which is a framework protocol, which indicates that its implementation classes are of the same type, or a set with similar characteristics. For the general program, the interface does not have any implementation, but in those special programs, the exception,

Data query every time you need to query data from the database, the database pressure is very large, query speed is slow, so set up the cache layer, query data from the Redis query, if the query is not, then query the database, and then put the database query data into a redis in a copy, You can find it directly from Redis the next time you query, and you don't need to query the database.

Company development and use Docker, each landing their own development machine always enter SSH [email protected]_string, and then confirm the input password, deft on hand also often will be wrong. As a lazy person, must find a trickery way, look at the next SSH command, because it to do once with the server encryption interaction, so there is no direct access to password login options, had to forget.

Return to the property access expression, if the expression follows "." and an identifier, it looks for the value of the property specified by the identifier and returns it as the value of the entire expression. If an object expression follows a heap of square brackets, the value of the expression inside the square brackets is computed and converted to a string, although both methods do not exist if the property is accessed. will return undefine. http://www.ty8153.com/

If a new contour or wind field is drawn directly without erasing, the new contour (wind field) is superimposed with the original contour (wind field), and there is no separate remove method for the contour and wind fields drawn, so if you want to erase the contour lines that have already been drawn, you will need to re-project the map again. If the accuracy of the map projection is a little higher, the whole projection process will be very long. By studying the return results of contours and wind fields, I found a way to erase contour lines and wind fields without having to re-project the map.

Internally, a service type (interface type) is created to the index of the implementation type, and the resolve is used to find the implementation type and create the instance.
This implementation is very simple, but there are a lot of problems, in order to achieve such a judgment through code, we have to understand the above these heights through what code to obtain? You can refer to a previous article I wrote "HTML element coordinate positioning, these knowledge points to grasp."

http://www.cnblogs.com/nyctu/

The benefit of this implementation of the singleton pattern is that the logic of implementation is simple, easy to read and use. The disadvantage is that because instance uses a class static field and is initialized directly, the instance is created directly when the JVM loads the class. And we may not always use that instance. If the constructor do sth part of the example is a very time-consuming part, it will result in the initial loading class, the system's responsiveness continues to rise, and there will always be instances of this object in the JVM heap, resulting in a waste of memory.

PS Some people may be difficult to understand, since the JVM loads the class, it means that we will use the object, why there is a scenario that the instance will not be used? Here's an example of a static field that needs to be used for this class, or a static method or the class being reflected, and the JVM will load the class.

Write an SSH automatic login script with Shebang