Java - InputStream 을 byte 배열로 변환

목차

1. readAllBytes()

inputstream의 readAllBytes()는 JAVA9 버전부터 이용이 가능합니다.

package com.example.logbacksample;

import lombok.extern.slf4j.Slf4j;
import org.apache.commons.io.IOUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.core.io.ResourceLoader;
import org.springframework.stereotype.Component;

import java.io.InputStream;

@Slf4j
@Component
public class ResourceApplicationRunner implements ApplicationRunner {
    @Autowired
    ResourceLoader resourceLoader;

    @Override
    public void run(ApplicationArguments args) throws Exception {
        InputStream inputStream = resourceLoader.getResource("classpath:res.txt").getInputStream();
        byte[] bytes = inputStream.readAllBytes();
        log.info("bytes : " + new String(bytes));
        inputStream.close();
    }
}

2. toByteArray()

package com.example.logbacksample;

import lombok.extern.slf4j.Slf4j;
import org.apache.commons.io.IOUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.core.io.ResourceLoader;
import org.springframework.stereotype.Component;

import java.io.InputStream;

@Slf4j
@Component
public class ResourceApplicationRunner implements ApplicationRunner {
    @Autowired
    ResourceLoader resourceLoader;

    @Override
    public void run(ApplicationArguments args) throws Exception {
        InputStream inputStream = resourceLoader.getResource("classpath:res.txt").getInputStream();
        byte[] byteArray = IOUtils.toByteArray(inputStream);
        log.info("byteArray : " + new String(bytes));
        inputStream.close();
    }
}