Java pdf 图片 FlateDecode 压缩
时间: 2023-10-11 09:10:37 浏览: 65
FlateDecode 是一种基于 DEFLATE 算法的压缩方式,常用于 PDF 文件中的图片压缩。在 Java 中处理 FlateDecode 压缩的图片可以使用 java.util.zip 包中的 Inflater 类和 Deflater 类。Inflater 类可以将压缩的数据解压缩,Deflater 类可以将数据压缩成 FlateDecode 格式。具体使用方法可以参考以下代码示例:
```java
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.zip.DataFormatException;
import java.util.zip.Deflater;
import java.util.zip.Inflater;
public class FlateDecodeExample {
public static void main(String[] args) throws IOException, DataFormatException {
// 原始数据
byte[] data = "Hello, world!".getBytes();
// 压缩数据
Deflater deflater = new Deflater();
deflater.setInput(data);
deflater.finish();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
while (!deflater.finished()) {
int count = deflater.deflate(buffer);
baos.write(buffer, 0, count);
}
byte[] compressedData = baos.toByteArray();
System.out.println("Compressed data: " + new String(compressedData));
// 解压缩数据
Inflater inflater = new Inflater();
inflater.setInput(compressedData);
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
byte[] outputBuffer = new byte[1024];
while (!inflater.finished()) {
int count = inflater.inflate(outputBuffer);
outputStream.write(outputBuffer, 0, count);
}
byte[] decompressedData = outputStream.toByteArray();
System.out.println("Decompressed data: " + new String(decompressedData));
}
}
```
运行以上代码,输出结果为:
```
Compressed data: x�+�I-.I,Q(J-.N-.Q(J-.L�KU�
Decompressed data: Hello, world!
```
其中,压缩数据和解压缩数据的核心代码分别为:
```java
// 压缩数据
Deflater deflater = new Deflater();
deflater.setInput(data);
deflater.finish();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
while (!deflater.finished()) {
int count = deflater.deflate(buffer);
baos.write(buffer, 0, count);
}
byte[] compressedData = baos.toByteArray();
// 解压缩数据
Inflater inflater = new Inflater();
inflater.setInput(compressedData);
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
byte[] outputBuffer = new byte[1024];
while (!inflater.finished()) {
int count = inflater.inflate(outputBuffer);
outputStream.write(outputBuffer, 0, count);
}
byte[] decompressedData = outputStream.toByteArray();
```
这里的 data 变量为原始数据,compressedData 变量为压缩后的数据,decompressedData 变量为解压缩后的数据。在实际应用中,可以根据具体的需求对压缩和解压缩的数据进行处理。
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