Project scenario ：

Tips ： Get the server address and then process the data

Now I know the server address , We upload the file to the server , Then if you want to save the file name or file suffix , It's going to cause problems , Then we need to process and analyze the string , You must analyze and summarize strings in the code , Then it can meet our existing project scenarios .

Problem description ：

Tips ： File name and suffix processing

The data we get is like this

        String fileSite = "http://192.168.1.22:8081/imgPortl /ReadImg/181217775991024.jpg";

According to the data we got , I found all kinds of strange symbols in it , If you use simple splict It must be impossible to achieve the effect , Because various symbols and file upload paths will affect our interception , At this time, we need to think of other methods to analyze and process data .

Cause analysis ：

Tips ：string String processing can solve this problem

We use the position and screenshot of the string, and then quickly find the data for processing , We can achieve the effect we need .

substring() The function of is to intercept a part of the parent string
The first parameter int Index for start , Corresponding String The starting position in the number ,
The second parameter is the index position of the cutoff , Corresponding String End position in
1、 The length of the obtained string is ：endIndex - beginIndex;
2、 from beginIndex Began to take , To endIndex end , from 0 Starting number , It does not include endIndex The character of position
Only with such data can we carry out the next analysis ,substring At this moment, the function of is more powerful than ever , At present, I only think that this treatment will be better solved , If there is a better way , Welcome to exchange .
Be careful ：
1)、substring(a,b) Parameters in a Its value can be from the index value 0 Start ,
When a be equal to 0 when , It means that it starts from the first character of the string ,
That is, its substring contains the first character , Of course , You can also start with other characters that follow ;
2)、substring(a,b) Parameters in b, The maximum value can be Length of parent string ,
But it does not contain the index value b The character of

Solution ：

//  File address 
  		String fileSite = "http://192.168.1.22:8081/imgPortl/ReadImg/181217775991024.jpg";
        //  File name 
        String oriName = fileSite.substring(fileSite.lastIndexOf("/")+1);
        //  file name 
        String substring = oriName.substring(0, oriName.lastIndexOf("."));
        System.out.println(substring); //  Output 

summary ：

1.xx.substring() The parameters in brackets are different , The effect will be very different , Detailed as follows ：

2.xx.substring(0,2) It means taking the first and second characters （0,1,2 It means the first 、 Two 、 Three characters , The principle of including the head but not the tail only includes the first 、 Two characters ）, Returns a new string （ Only the first and second characters specified ）;

3.xx.substring(2) It means to remove the first two characters , Returns a new string （ It only contains the remaining string after removing the first two characters ）

4. In this method beginIndex Indicates the starting index of the interception , The intercepted string contains the characters corresponding to the starting index ;endIndex Indicates end index , The intercepted string does not include the characters corresponding to the ending index , If you don't specify endIndex, It indicates that it is intercepted to the end of the target string . This method is used to extract position beginIndex And location endIndex The string part between positions .