Java特殊字符编码问题：JSON读取后乱码求助

Hey there! Let's break down why your name Martin Perénya is showing up as Martin Perénya—it's all about character encoding mismatches. Here's what's happening and how to fix it:

The Root Cause #

Your FileReader is using your operating system's default character set (like GBK on Windows) to read the raw.json file, but your JSON file is almost certainly saved in UTF-8 (the universal standard for JSON). When the reader encounters UTF-8 characters like é, it misinterprets them using the wrong encoding, leading to that garbled text.

The Fix #

Replace FileReader with InputStreamReader and explicitly specify UTF-8 encoding. This ensures your code reads the file correctly no matter what system it's running on.

Modified Code #

Here's your updated getAll() method with the fix and some null-safety improvements to avoid common pitfalls:

package main.service;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
import java.text.SimpleDateFormat;
import java.util.Date;
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;

public class Service {
    public String getAll() throws FileNotFoundException {
        JsonParser jsonParser = new JsonParser();
        // Replace FileReader with InputStreamReader to enforce UTF-8 encoding
        InputStreamReader reader = new InputStreamReader(
            new FileInputStream("raw.json"), 
            StandardCharsets.UTF_8
        );
        
        JsonObject data = (JsonObject) jsonParser.parse(reader);
        JsonArray issues = data.get("issues").getAsJsonArray();
        JsonArray processedIssues = new JsonArray();

        for(JsonElement i : issues) {
            JsonObject object = new JsonObject();
            JsonObject issue = (JsonObject) i;
            JsonObject fields = issue.get("fields").getAsJsonObject();
            
            // Handle null cases first to avoid NullPointerExceptions
            JsonObject assignee = fields.get("assignee").getAsJsonObject();
            String name = "None";
            
            if (assignee != null && assignee.size() > 0) {
                JsonElement nameElement = assignee.get("displayName");
                if (nameElement != null && !nameElement.getAsString().isEmpty()) {
                    name = nameElement.getAsString();
                }
            }
            
            object.addProperty("name", name);
            processedIssues.add(object);
        }

        JsonObject returnData = new JsonObject();
        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        String dateString = format.format(new Date());
        returnData.addProperty("created", dateString);
        returnData.add("featureList", processedIssues);
        
        System.out.println("returnedData - " + returnData);
        return returnData.toString();
    }
}

Key Changes Explained #

• InputStreamReader with UTF-8: This forces the file to be read using the correct encoding for JSON, which directly fixes the garbled character issue.
• Null safety checks: Added guards for assignee being null and displayName being empty to prevent crashes—something every new Java dev should get in the habit of doing!

Quick Additional Checks #

• Double-check your raw.json file is saved in UTF-8: Open it in a text editor like Notepad++ and confirm the encoding setting (look in the "Encoding" menu).
• If you later write this data to a file, make sure to use UTF-8 there too (e.g., OutputStreamWriter with StandardCharsets.UTF_8).

内容的提问来源于stack exchange，提问作者Lynskey08