发表新帖
发表新帖

java: how to convert this string to ArrayList?

后端 未结
关注
4 1604
说谎
说谎 2021-01-28 01:47 
String text = \'[[\"item1\",\"item2\",\"item3\"], [\"some\", \"item\"], [\"far\", \"out\", \"string\"]]\';

I would like to iterate over each individual

4条回答
  • 时光取名叫无心
    时光取名叫无心 (楼主)
    2021-01-28 02:32

    Here's a simple parser, it should deal with all kinds of abusive nesting and will be robust to single and double quotes -- but it won't care if you mix them 'test" is treated equivalent to "test".

    edit: added comments, and now it deals with escaped quotes in strings. (and now improved string token handling even more)

    import java.io.IOException;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.List;

public class StringToList {

    public static void main(String[] args) throws IOException{
        StringReader sr = new StringReader("[[\"it\\\"em1\", \"item2\",\"item3\"], [\"some\",\"item\"], [\"far\",\"out\",\"string\"]]");
        System.out.println(tokenize(sr));
    }

    @SuppressWarnings({ "rawtypes", "unchecked" })
    public static List tokenize(StringReader in) throws IOException{
        List stack = new ArrayList();
        int c;
        while((c = in.read()) != -1){
            switch(c){
            case '[':
                // found a nested structure, recurse..
                stack.add(tokenize(in));
                break;
            case ']':
                // found the end of this run, return the
                // current stack
                return stack;
            case '"':
            case '\'':
                // get the next full string token
                stack.add(stringToken(in));
                break;
            }
        }

        // we artificially start with a list, though in principle I'm
        // defining the string to hold only a single list, so this
        // gets rid of the one I created artifically.
        return (List)stack.get(0);
    }

    public static String stringToken(StringReader in) throws IOException{
        StringBuilder str = new StringBuilder();
        boolean escaped = false;
        int c;
        outer: while((c = in.read()) != -1){
            switch(c){
            case '\\':
                escaped = true;
                break;
            case '"':
            case '\'':
                if(escaped){
                    escaped = false;
                }else{
                    break outer;
                }
            default:
                str.append((char)c);
            }
        }
        return str.toString();
    }

}



    Just a couple of notes: this won't enforce your syntax to be correct, so if you do something goofy with the quotes, like I described, it might still get parsed as (un)expected.  Also, I don't enforce commas at al, you don't even need a space between the quotes, so ["item1""item2"] is just as valid using this parser as ["item1", "item2"], but perhaps more oddly, this thing should also deal with ["item1"asdf"item2"] ignoring asdf.
    
    
    
             
    
                                                        
    
            
            
    
              
                
                0
              
                   
                
               讨论(0)
              
                                                  
              
              
    
                          
             
       
          
              
    
                                       
    

    

                
    
                         
          
                              			
        
        
        
    
          
    
            
            
    
              
              
    
            
    


                                 
              
    
            
    
                          
    

        
         
    
                
                
    
                  
                
    
                
    
                   看不清?
                
    
              
    
                                  
    
                    
   
                 
             
              
    提交回复
    
            
    
          
    
        
    
      
       
      
    
    
    
          
 
     
 
    
        
    热议问题