Java：常用的将InputStream转化为String的方法

我不是女神ヾ 2023-06-28 04:50 15阅读 0赞

**目录**

一、Google Guava IO

1、使用com.google.common.io.ByteSource

2、使用com.google.common.io.CharStreams

二、Apache Commons IO

1、使用org.apache.commons.io.IOUtils.copy()

2、使用org.apache.commons.io.IOUtils.toString()

三、JDK

1、使用java.util.Scanner

2、使用java.io.ByteArrayOutputStream

3、使用java.io.InputStream.readAllBytes() （since JDK9）

--------------------

由于将InputStream转化为String使用很频繁，所以将常用的几种方式列举如下：

## 一、Google Guava IO ##

> <dependency>  
>     <groupId>com.google.guava</groupId>  
>     <artifactId>guava</artifactId>  
>     <version>28.2-jre</version>  
> </dependency>

### 1、使用com.google.common.io.ByteSource ###

// com.google.common.io.ByteSource
    public static String toString(InputStream inputStream) throws IOException {
    
        ByteSource byteSource = new ByteSource() {
    
            public InputStream openStream() throws IOException {
                return inputStream;
            }
        };
    
        return byteSource.asCharSource(StandardCharsets.UTF_8).read();
    }

### 2、使用com.google.common.io.CharStreams ###

// com.google.common.io.CharStreams
    public static String toString(InputStream inputStream) throws IOException {
    
        String text = null;
    
        try (final Reader reader = new InputStreamReader(inputStream, StandardCharsets.UTF_8)) {
            text = CharStreams.toString(reader);
        }
    
        return text;
    }

##    二、Apache Commons IO ##

> <dependency>  
>     <groupId>commons-io</groupId>  
>     <artifactId>commons-io</artifactId>  
>     <version>2.6</version>  
> </dependency>

### 1、使用org.apache.commons.io.IOUtils.copy() ###

public static String toString(InputStream inputStream) throws IOException {
    
        StringWriter writer = new StringWriter();
        IOUtils.copy(inputStream, writer, StandardCharsets.UTF_8);
        return writer.toString();
    }

### 2、使用org.apache.commons.io.IOUtils.toString() ###

public static String toString(InputStream inputStream) throws IOException {
    
        return IOUtils.toString(inputStream, StandardCharsets.UTF_8);
    }

## 三、JDK ##

### 1、使用java.util.Scanner ###

public static String toString(InputStream inputStream) throws IOException {
    
        // \A The beginning of the input
        // \Z The end of the input but for the final terminator, if any
        // \z The end of the input
        try (Scanner scanner = new Scanner(inputStream, StandardCharsets.UTF_8.name());) {
            scanner.useDelimiter("\\A");
            return scanner.hasNext() ? scanner.next() : "";
        }
    }

### 2、使用java.io.ByteArrayOutputStream ###

public static String toString(InputStream inputStream) throws IOException {
    
        ByteArrayOutputStream bout = new ByteArrayOutputStream();
        byte[] buf = new byte[256];
        int len = 0;
        while ((len = inputStream.read(buf)) != -1) {
            bout.write(buf, 0, len);
        }
    
        return bout.toString(StandardCharsets.UTF_8.name());
    }

### 3、使用java.io.InputStream.readAllBytes()（since JDK9） ###

public static String toString(InputStream inputStream) throws IOException {
            // since JDK9
    	 return new String(inputStream.readAllBytes(), StandardCharsets.UTF_8);
    }

**参考文档**

[Convert InputStream to String In Java][]

[How to convert InputStream to String in Java][]

[Convert InputStream to String In Java]: https://howtodoinjava.com/java/io/how-to-read-data-from-inputstream-into-string-in-java/
[How to convert InputStream to String in Java]: https://www.mkyong.com/java/how-to-convert-inputstream-to-string-in-java/