Java InputStream 中文乱码

一、问题描述

在调用 http POST ，获取请求体中的内容时，如果出现中文，在读取的时候，可能会引起“中文乱码”的现象。

如下读取方式 会 引起中文乱码：

public XssRequestWrapper(HttpServletRequest request) throws IOException {
        super(request);
        this.request = request;
        StringBuilder stringBuilder = new StringBuilder();
        BufferedReader bufferedReader = null;
        try {
            InputStream inputStream = request.getInputStream();
            if (inputStream != null) {
                // 如下方式读取 InputStream 流，会引发中文乱码问题
                bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
                char[] charBuffer = new char[128];
                int bytesRead = -1;
                while ((bytesRead = bufferedReader.read(charBuffer)) > 0) {
                    stringBuilder.append(charBuffer, 0, bytesRead);
                }
            } else {
                stringBuilder.append("");
            }
        } catch (IOException ex) {
            throw ex;
        } finally {
            if (bufferedReader != null) {
                try {
                    bufferedReader.close();
                } catch (IOException ex) {
                    throw ex;
                }
            }
        }

        System.out.println("stringBuilder: " + stringBuilder.toString());
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32

二、问题原因

在不设置编码的情况下，InputStreamReader 默认的读取编码是 ASCII 编码，中文会转成乱码。

三、解决方案

在 InputStreamReader 读取时，需要指定读取的编码格式为 UTF_8 编码

如下读取方式 不会 引起中文乱码：

public XssRequestWrapper(HttpServletRequest request) throws IOException {
        super(request);
        this.request = request;
        StringBuilder stringBuilder = new StringBuilder();
        BufferedReader bufferedReader = null;
        try {
            InputStream inputStream = request.getInputStream();
            if (inputStream != null) {
                // 此处需要将编码格式设置为UTF_8，解决 InputStream 流读取时的中文乱码问题
                bufferedReader = new BufferedReader(new InputStreamReader(inputStream, StandardCharsets.UTF_8));
                char[] charBuffer = new char[128];
                int bytesRead = -1;
                while ((bytesRead = bufferedReader.read(charBuffer)) > 0) {
                    stringBuilder.append(charBuffer, 0, bytesRead);
                }
            } else {
                stringBuilder.append("");
            }
        } catch (IOException ex) {
            throw ex;
        } finally {
            if (bufferedReader != null) {
                try {
                    bufferedReader.close();
                } catch (IOException ex) {
                    throw ex;
                }
            }
        }

        System.out.println("stringBuilder: " + stringBuilder.toString());
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32