Java中数组内字符串转Integer抛出“Unknown Source Error”问题

Hey there! Let's dig into that frustrating "Unknown Source Error" you're hitting when trying to parse poi_id from your CSV data. That generic error message is usually masking a more specific issue with the data itself or how you're processing it—let's break down the most likely culprits and fixes:

Common Causes & Fixes #

1. Hidden Whitespace in the poi_id Field #

CSV lines often have accidental spaces around values (like user_id, 456, times_visited). When you split on commas, the poi_id string ends up being " 456" instead of "456"—and Integer.parseInt() can't handle leading/trailing spaces.

Fix: Trim the string before parsing:

int poiId = Integer.parseInt(parts[1].trim());

2. Non-Numeric or Empty poi_id Values #

If any row has a poi_id that's not a pure number (like user_id, abc789, times_visited) or is empty (user_id, , times_visited), parseInt() will throw a NumberFormatException—which might get wrapped into that vague "Unknown Source" error.

Fix: Add validation before parsing to catch bad data:

String poiIdStr = parts[1].trim();
if (!poiIdStr.isEmpty() && poiIdStr.matches("\\d+")) {
    int poiId = Integer.parseInt(poiIdStr);
    // Add to your poi_list here
} else {
    // Log or handle invalid entries instead of crashing
    System.err.println("Skipping line with invalid poi_id: " + poiIdStr);
}

3. Malformed CSV Lines (Incorrect Number of Fields) #

If some rows don't have exactly 3 values (e.g., a missing field like user_id, times_visited), splitting the line will give you an array shorter than 3 elements. Trying to access parts[1] here will throw an ArrayIndexOutOfBoundsException, which could also show up as an "Unknown Source" error.

Fix: Validate the split array length first:

String[] parts = line.split(",");
if (parts.length == 3) {
    // Proceed with parsing
} else {
    System.err.println("Skipping malformed line: " + line);
}

4. Capture Specific Exceptions for Debugging #

That "Unknown Source" error is likely because you're not catching the specific exception thrown by parseInt(). Wrapping the parsing code in a try-catch block will reveal the exact issue.

Fix: Add exception handling to get clear debug info:

try {
    int poiId = Integer.parseInt(parts[1].trim());
    poi_list.add(new POI(poiId, ...)); // Adjust to match your POI constructor
} catch (NumberFormatException e) {
    System.err.println("Failed to parse poi_id from line: " + line);
    e.printStackTrace(); // This will show the full stack trace to pinpoint the problem
} catch (ArrayIndexOutOfBoundsException e) {
    System.err.println("Line has missing fields: " + line);
    e.printStackTrace();
}

Quick Summary #

Start by trimming whitespace from the poi_id string, then validate that your CSV lines are properly formatted and contain numeric poi_id values. Adding specific exception handling will help you debug exactly which lines are causing the issue instead of dealing with that vague "Unknown Source" error.

内容的提问来源于stack exchange，提问作者Efthimis_28