SpringUsefulUtilClassTests.java

import org.junit.Test;
import org.springframework.beans.BeanWrapper;
import org.springframework.beans.BeanWrapperImpl;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.retry.support.RetryTemplate;
import org.springframework.util.FileCopyUtils;
import org.springframework.util.FileSystemUtils;
import org.springframework.web.client.RestTemplate;

import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.stream.Stream;

public class SpringUsefulUtilClassTests {

	/**
	 * FileCopyUtils.class
	 * FileSystemUtils.class
	 * file과 stream 을 쉽게 컨트롤 할 수 있는 유틸
	 * @throws Exception
	 */
	@Test
	public void fileUtilsTest() throws Exception {
		String sampleDir = System.getProperty("user.home") + "/sample";
		String sampleTestDir = sampleDir + "/test";
		Path samplePath = Files.createDirectories(Paths.get(sampleTestDir));
		Path sampleFile = Files.createFile(Paths.get(samplePath.toRealPath() + "/test.log"));

		// 파일에 문자열 적기
		FileCopyUtils.copy("test 파일 내용입니다 ^^".getBytes("utf-8"), sampleFile.toFile());

		// 파일 내용 가져오기
		System.out.println(FileCopyUtils.copyToString(new FileReader(sampleFile.toFile())));

		// 폴더 복사하기
		FileSystemUtils.copyRecursively(new File(sampleTestDir), new File(sampleTestDir + "_back"));

		// 폴더 제거하기
		FileSystemUtils.deleteRecursively(new File(sampleDir));
	}

	/**
	 * Http 요청을 쉽게 할 수 있는 형태를 제공
	 * @throws Exception
	 */
	@Test
	public void restTemplateTest() throws Exception {
		RestTemplate rt = new RestTemplate();
		String contents = rt.getForObject("http://daum.net", String.class);
		FileCopyUtils.copy(contents.getBytes("utf-8"), new File(System.getProperty("user.home") + "/daum.html"));
		System.out.println(contents);
	}

	/**
	 * RetryTemplate.class
	 * 현재 로직을 쉽게 재시도할 수 있도록 하는 형태를 제공
	 */
	@Test
	public void retryTemplateTest() {
		RetryTemplate r = new RetryTemplate();
		r.execute(retryContext -> {
			System.out.println("Hello world! (retry count:" + (retryContext.getRetryCount() + 1) + ")");
			if (true) {
				throw new RuntimeException("test");
			}
			return Void.class;
		}, retryContext -> {
			System.out.printf("All(%d) fail!!!\n", retryContext.getRetryCount());
			return Void.class;
		});
	}

	/**
	 * BeanWrapper.class
	 * Java Bean 을 다이나믹하게 접근할 수 있는 형태를 제공
	 */
	@Test
	public void beanWrapperTest() {
		TestBean bean = new TestBean();
		bean.setName("aaa");
		bean.setId("1");
		BeanWrapper bw = new BeanWrapperImpl(bean);
		bw.setPropertyValue("id", "aaa");
		bw.setPropertyValue("name", "bbb");
		Stream.of(bw.getPropertyDescriptors()).forEach(System.out::println);
		Object wrappedInstance = bw.getWrappedInstance();
		System.out.println(wrappedInstance);
	}

	/**
	 * PathMatchingResourcePatternResolver.class
	 * Ant 패턴을 이용하여 리소스에 쉽게 접근 가능
	 * @throws IOException
	 */
	@Test
	public void pathMatchingResourcePatternResolverTest() throws IOException {
		PathMatchingResourcePatternResolver resourcePatternResolver = new PathMatchingResourcePatternResolver();
		Resource[] resources = resourcePatternResolver.getResources("file:" + System.getProperty("user.home") + "/git/spring-boot/**/*.java");
		Stream.of(resources).forEach(System.out::println);
	}
}