MySQL大文本压缩方案探索

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1、MySQL自带函数compress，uncompress

• 数据库压缩的话需要牺牲部分cpu运算能力

• 字段越大，压缩率越高

SELECT COMPRESS(b.text) from business b WHERE b.businessId=1;

2、服务端代码压缩字符串

• Gzip：压缩率高 GzipInputStream

import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.nio.charset.StandardCharsets;
import java.util.Objects;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;

@Slf4j
public class GZipUtil {

    public static byte[] compress(String str) {
        if (StringUtils.isEmpty(str)) return null;

        try (ByteArrayOutputStream out = new ByteArrayOutputStream();
             GZIPOutputStream gzip = new GZIPOutputStream(out)) {
            gzip.write(str.getBytes(StandardCharsets.UTF_8));
            gzip.close();
            return out.toByteArray();
        } catch (Exception e) {
            log.error("gzip压缩失败", e);
            return new byte[]{};
        }
    }

    public static String uncompress(byte[] bytes) {
        if (Objects.isNull(bytes)) return null;
        try (ByteArrayOutputStream out = new ByteArrayOutputStream();
             ByteArrayInputStream in = new ByteArrayInputStream(bytes)){
            GZIPInputStream ungzip = new GZIPInputStream(in);
            byte[] buffer = new byte[1024];
            int n;
            while ((n = ungzip.read(buffer)) >= 0) {
                out.write(buffer, 0, n);
            }
            return new String(out.toByteArray(), StandardCharsets.UTF_8);
        } catch (Exception e) {
            log.error("gzip解压失败", e);
            return new String();
        }
    }

    public static void main(String[] args) {
        String org = "selct **";
        byte[] encode = GZipUtil.compress(org);
        System.out.println("压缩前字符串:" + org);
        System.out.println("压缩前长度:" + org.length());
        System.out.println("压缩后长度:" + encode.length);
        System.out.println("解压后字符串：" + GZipUtil.uncompress(encode));
    }

}