为何str.trim()无法移除特定单词的全部空白符？Java解析类汇编代码疑问

Hey there! Let’s work through refining your assembly-like code parsing workflow. You’ve already nailed the first critical step—reading lines from the text file into a String array while preserving whitespace is a solid foundation. Now, let’s fix up the splitting and trimming logic to avoid common pitfalls and get clean, structured data.

Common Issues with Basic split(" ") #

Using str.split(" ") directly can create annoying empty strings in your results, especially if lines have consecutive spaces, leading, or trailing whitespace. For example, a line like MOV R1, R2 #Load value would split into ["MOV", "", "R1,", "R2", "", "#Load", "value"]—those empty entries are just noise we don’t need.

Solution 1: Split on Any Whitespace (Recommended) #

Use split("\\s+") to split on one or more whitespace characters (spaces, tabs, etc.). This automatically skips consecutive gaps and avoids empty elements. Here’s a full implementation:

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

public class AssemblyParser {
    public static void main(String[] args) {
        // Example pre-loaded lines from your file
        String[] lines = {
            "MOV  R1, R2  #Load register value",
            "ADD  R3, R1",
            "STORE R4  0x100"
        };

        List<List<String>> parsedInstructions = new ArrayList<>();

        for (String line : lines) {
            // Split on one or more whitespace characters
            String[] rawParts = line.split("\\s+");
            // Trim each part (extra safe, though split("\\s+") already removes surrounding whitespace)
            List<String> trimmedParts = Arrays.stream(rawParts)
                                             .map(String::trim)
                                             .collect(Collectors.toList());
            parsedInstructions.add(trimmedParts);
        }

        // Convert to a 2D String array if needed for your use case
        String[][] parsedArray = parsedInstructions.stream()
                                                   .map(list -> list.toArray(new String[0]))
                                                   .toArray(String[][]::new);

        // Verify the result
        for (String[] instruction : parsedArray) {
            System.out.println(Arrays.toString(instruction));
        }
    }
}

Solution 2: Filter Empty Strings After Splitting #

If you specifically need to split on single spaces (for edge cases where single spaces hold meaning), split with split(" ") then filter out empty strings after trimming:

for (String line : lines) {
    String[] rawParts = line.split(" ");
    List<String> trimmedParts = Arrays.stream(rawParts)
                                     .map(String::trim)
                                     .filter(part -> !part.isEmpty()) // Remove empty entries
                                     .collect(Collectors.toList());
    parsedInstructions.add(trimmedParts);
}

Bonus: Preserve Entire Comments as Single Elements #

If your assembly code uses comments (e.g., starting with #), you might want to keep each comment as a single element instead of splitting it into words. Here’s how to handle that:

for (String line : lines) {
    // Split line into instruction and comment sections (max 2 parts total)
    String[] lineSegments = line.split("#", 2);
    
    // Process the instruction part
    String instructionSegment = lineSegments[0].trim();
    List<String> instructionParts = Arrays.stream(instructionSegment.split("\\s+"))
                                         .filter(part -> !part.isEmpty())
                                         .collect(Collectors.toList());
    
    // Add the full comment as one element if it exists
    if (lineSegments.length > 1) {
        String comment = "#" + lineSegments[1].trim();
        instructionParts.add(comment);
    }
    
    parsedInstructions.add(instructionParts);
}

This turns a line like MOV R1, R2 #Load value into R2 into ["MOV", "R1,", "R2", "#Load value into R2"], keeping the comment intact as a single entry.

内容的提问来源于stack exchange，提问作者user9330135