Java 从InputStream中删除换行符

我想从

java.io.InputStream

中删除所有换行符（用于\n和\r\n），读取文件时，相应的方法如下所示：

/**
 * @param target {@linkplain File}
 * @return {@linkplain InputStream}
 * @throws Exception
 */
protected InputStream initInput(final File file)
    throws Exception {
    InputStream stream = null;
    try {
        if (file.isDirectory()) {
            // throw exception
        }
        if (!file.exists()) {
            // throw another exception
        }
        // 
        // *remove newlines here*
        //
        stream = new FileInputStream(file);

    } catch (FileNotFoundException e) {
        // throw another exception
    }
    return stream;
}

---

有时，标准Java库无法提供足够的方法来操作其核心类。ApacheCommonsLang提供了这些额外的方法

---

如果您可以使用该库，则该方法可能很有用。

您可以将其转换为字符串，并将新行字符替换为零：

InputStream is = new ByteArrayInputStream("file content".getBytes());

    //read it with BufferedReader
    BufferedReader br  = new BufferedReader(new InputStreamReader(is));

    StringBuilder sb = new StringBuilder();

    String line;
    while ((line = br.readLine()) != null) {
        sb.append(line.replace("\r","").replace("\n",""))       


    System.out.println(sb.toString());

---

考虑到您的文本不包含与您相关的“\n”和“\r”，这将是一件好事。

您可以自己实现

java.io.FileInputStream

，并在阅读时跳过

\r

和

\n

覆盖读取方法

Hier是示例实现（没有任何错误处理）

对于一些基本测试

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import junit.framework.Assert;

import org.junit.BeforeClass;
import org.junit.Test;

public class NoNewLineFileInputStreamTest {

    private final static String txt = "testnl.txt";

    @BeforeClass
    public static void genTestFile() throws IOException {
        OutputStream os = new FileOutputStream(txt);
        os.write((
                "Hello\n" +
                ",\r\n" +
                "World!\r" +
                "").getBytes());
        os.close();
    }

    @Test
    public void readInt() throws IOException {
        InputStream is = new NoNewLineFileInputStream(txt);
        int c = is.read();
        while(c != -1) {
            Assert.assertTrue(c != '\n' && c != '\r');
            c = is.read();
        }
        is.close();
    }

    @Test
    public void readBytes() throws IOException {
        InputStream is = new NoNewLineFileInputStream(txt);
        int l = is.available();
        if(l > 0) {
            byte[] content = new byte[l];
            int n = is.read(content);
            String expected = "Hello,World!";
            Assert.assertEquals(expected.getBytes().length, n);
            Assert.assertEquals(expected, new String(content, 0, n));
        }
        is.close();
    }

    @Test
    public void readBytesOffset() throws IOException {
        InputStream is = new NoNewLineFileInputStream(txt);
        int l = is.available();
        if(l > 0) {
            byte[] content = new byte[l*3];
            int n = is.read(content, 3, 5);
            String expected = "Hello";
            Assert.assertEquals(expected.getBytes().length, n);
            Assert.assertEquals(expected, new String(content, 3, n));
        }
        is.close();
    }
}

您的方法如下所示

/**
 * @param target {@linkplain File}
 * @return {@linkplain InputStream}
 * @throws Exception
 */
protected InputStream initInput(final File file)
    throws Exception {
    InputStream stream = null;
    try {
        if (file.isDirectory()) {
            // throw exception
        }
        if (!file.exists()) {
            // throw another exception
        }
        // 
        // read operations using this implementation will jump over all '\n' and '\r'
        //
        stream = new NoNewLineFileInputStream(file);

    } catch (FileNotFoundException e) {
        // throw another exception
    }
    return stream;
}

为了更好地与

java.io.InputStream

抽象类兼容，您可能需要覆盖类中的所有方法

/**
 * @param target {@linkplain File}
 * @return {@linkplain InputStream}
 * @throws Exception
 */
protected InputStream initInput(final File file)
    throws Exception {
    InputStream stream = null;
    try {
        if (file.isDirectory()) {
            // throw exception
        }
        if (!file.exists()) {
            // throw another exception
        }
        // 
        // read operations using this implementation will jump over all '\n' and '\r'
        //
        stream = new NoNewLineFileInputStream(file);

    } catch (FileNotFoundException e) {
        // throw another exception
    }
    return stream;
}