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Java Base64 Encoder Methods - Java 147

Java Base64 Encoder Methods – Java 147

Java Base64 Encoder Methods

在 Java 中提供 Base64 編碼器，將輸入映射到 A-Z 、 a-z 、 0-9 、 +/ 字元集中的一組字元，輸出編碼字串的長度必須是四的倍數，若不足夠，會根據需要在輸出末尾添加一兩個填充字元 (=)，以滿足此要求，同時也使用 Apache Commons Codec 的實用 API 進行編碼， Base64 Encoder Java Methods 本篇增加了範例，並透過單元測試來驗證產出結果。

檔案目錄

./
   +- src
       +- test
       |   +- org
       |       +- ruoxue
       |           +- java_147
       |               +- base64
       |                   +- basic
       |                       +- Base64EncoderMethodsTest.java

單元測試

Base64 Encoder Methods Java 提供 Base64 基本編碼器操作，將 byte[] 編碼成 Base64 。

encode

建立一個 String ，轉成 byte[] ，使用 Base64.Encoder 進行編碼。

	@Test
	public void encode() throws Exception {
		Base64.Encoder encoder = Base64.getEncoder();
		String value = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
		System.out.println(value);
		byte[] result = encoder.encode(value.getBytes(StandardCharsets.UTF_8.toString()));
		System.out.println(result);
		String stringResult = new String(result);
		System.out.println(stringResult);
		assertThat(stringResult)
				.isEqualTo("QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVphYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3h5ejAxMjM0NTY3ODkrLw==");
	}
ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/
[B@6aa8ceb6
QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVphYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3h5ejAxMjM0NTY3ODkrLw==

encodeWithoutPadding

Base64 Encoder Methods Java 建立一個 String ，轉成 byte[] ，使用 Base64.Encoder 不進行填充的編碼。

	@Test
	public void encodeWithoutPadding() throws Exception {
		Base64.Encoder encoder = Base64.getEncoder();
		String value = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
		System.out.println(value);
		byte[] result = encoder.withoutPadding().encode(value.getBytes(StandardCharsets.UTF_8.toString()));
		System.out.println(result);
		String stringResult = new String(result);
		System.out.println(stringResult);
		assertThat(stringResult)
				.isEqualTo("QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVphYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3h5ejAxMjM0NTY3ODkrLw");
	}
ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/
[B@6aa8ceb6
QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVphYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3h5ejAxMjM0NTY3ODkrLw

encodeWithDst

Base64 Encoder Methods Java 建立一個 String ，轉成 byte[] 使用 Base64.Encoder 進行編碼，將結果存放到另一個陣列。

	@Test
	public void encodeWithDst() throws Exception {
		Base64.Encoder encoder = Base64.getEncoder();
		String value = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
		System.out.println(value);
		int size = 100;
		byte[] dst = new byte[size];
		int result = encoder.encode(value.getBytes(StandardCharsets.UTF_8.toString()), dst);
		System.out.println(result);
		String stringResult = new String(dst);
		System.out.println(stringResult);
		assertThat(stringResult)
				.containsIgnoringWhitespaces(
						"QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVphYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3h5ejAxMjM0NTY3ODkrLw==")
				.hasSize(size);
	}
ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/
88
QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVphYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3h5ejAxMjM0NTY3ODkrLw==

encodeWithByteBuffer

Base64 Encoder Methods Java 建立一個 String ，轉成 byte[] 包裝成 ByteBuffer ，使用 Base64.Encoder 進行編碼，傳回 ByteBuffer 。

	@Test
	public void encodeWithByteBuffer() throws Exception {
		Base64.Encoder encoder = Base64.getEncoder();
		String value = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
		ByteBuffer byteBuffer = ByteBuffer.wrap(value.getBytes(StandardCharsets.UTF_8.toString()));
		System.out.println(byteBuffer);
		ByteBuffer result = encoder.encode(byteBuffer);
		System.out.println(result);
		String stringResult = new String(result.array(), StandardCharsets.UTF_8.toString());
		System.out.println(stringResult);
		assertThat(stringResult)
				.isEqualTo("QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVphYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3h5ejAxMjM0NTY3ODkrLw==");
	}
java.nio.HeapByteBuffer[pos=0 lim=64 cap=64]
java.nio.HeapByteBuffer[pos=0 lim=88 cap=88]
QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVphYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3h5ejAxMjM0NTY3ODkrLw==

encodeToString

Base64 Encoder Methods 建立一個 String ，轉成 byte[] 使用 Base64.Encoder 進行編碼，傳回字串。

	@Test
	public void encodeToString() throws Exception {
		Base64.Encoder encoder = Base64.getEncoder();
		String value = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
		System.out.println(value);
		String result = encoder.encodeToString(value.getBytes(StandardCharsets.UTF_8.toString()));
		System.out.println(result);
		assertThat(result)
				.isEqualTo("QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVphYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3h5ejAxMjM0NTY3ODkrLw==");
	}
ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/
QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVphYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3h5ejAxMjM0NTY3ODkrLw==

wrap

Base64 Encoder Methods 建立一個檔案 ，使用 Base64.Encoder 進行編碼，將結果輸出到另一個檔案。

	@Test
	public void wrap() throws Exception {
		Path src = Paths.get("./", "README.md");
		System.out.println(src);
		Path dst = Paths.get("./", "README.log");
		System.out.println(dst);
		Base64.Encoder encoder = Base64.getEncoder();
		try (OutputStream output = Files.newOutputStream(dst)) {
			long result = Files.copy(src, encoder.wrap(output));
			System.out.println(result);
			// OutputStream encodedStrem = encoder.wrap(output);
		}
	}

./README.md
./README.log
1214

Base64_encodeBase64

建立一個 String ，轉成 byte[] 使用 Apache Commons Codec 套件 Base64 進行編碼。

	@Test
	public void Base64_encodeBase64() throws Exception {
		String value = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
		System.out.println(value);
		byte[] result = org.apache.commons.codec.binary.Base64
				.encodeBase64(value.getBytes(StandardCharsets.UTF_8.toString()));
		System.out.println(result);
		String stringResult = new String(result);
		System.out.println(stringResult);
		assertThat(stringResult)
				.isEqualTo("QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVphYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3h5ejAxMjM0NTY3ODkrLw==");
	}
ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/
[B@4c98385c
QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVphYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3h5ejAxMjM0NTY3ODkrLw==

Base64_encodeBase64String

建立一個 String ，轉成 byte[] 使用 Apache Commons Codec 套件 Base64 進行編碼，傳回字串。

	@Test
	public void Base64_encodeBase64String() throws Exception {
		String value = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
		System.out.println(value);
		String result = org.apache.commons.codec.binary.Base64
				.encodeBase64String(value.getBytes(StandardCharsets.UTF_8.toString()));
		System.out.println(result);
		assertThat(result)
				.isEqualTo("QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVphYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3h5ejAxMjM0NTY3ODkrLw==");
	}
ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/
QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVphYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3h5ejAxMjM0NTY3ODkrLw==

Base64EncoderMethodsTest.java

Base64 Encoder Methods in Java 新增單元測試，驗證 Base64 Encoder Functions in Java 是否符合預期。

package org.ruoxue.java_147.base64.basic;

import static org.assertj.core.api.Assertions.assertThat;

import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Base64;

import org.junit.Test;

public class Base64EncoderMethodsTest {

	@Test
	public void encode() throws Exception {
		Base64.Encoder encoder = Base64.getEncoder();
		String value = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
		System.out.println(value);
		byte[] result = encoder.encode(value.getBytes(StandardCharsets.UTF_8.toString()));
		System.out.println(result);
		String stringResult = new String(result);
		System.out.println(stringResult);
		assertThat(stringResult)
				.isEqualTo("QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVphYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3h5ejAxMjM0NTY3ODkrLw==");
	}

	@Test
	public void encodeWithoutPadding() throws Exception {
		Base64.Encoder encoder = Base64.getEncoder();
		String value = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
		System.out.println(value);
		byte[] result = encoder.withoutPadding().encode(value.getBytes(StandardCharsets.UTF_8.toString()));
		System.out.println(result);
		String stringResult = new String(result);
		System.out.println(stringResult);
		assertThat(stringResult)
				.isEqualTo("QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVphYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3h5ejAxMjM0NTY3ODkrLw");
	}

	@Test
	public void encodeWithDst() throws Exception {
		Base64.Encoder encoder = Base64.getEncoder();
		String value = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
		System.out.println(value);
		int size = 100;
		byte[] dst = new byte[size];
		int result = encoder.encode(value.getBytes(StandardCharsets.UTF_8.toString()), dst);
		System.out.println(result);
		String stringResult = new String(dst);
		System.out.println(stringResult);
		assertThat(stringResult)
				.containsIgnoringWhitespaces(
						"QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVphYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3h5ejAxMjM0NTY3ODkrLw==")
				.hasSize(size);
	}

	@Test
	public void encodeWithByteBuffer() throws Exception {
		Base64.Encoder encoder = Base64.getEncoder();
		String value = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
		ByteBuffer byteBuffer = ByteBuffer.wrap(value.getBytes(StandardCharsets.UTF_8.toString()));
		System.out.println(byteBuffer);
		ByteBuffer result = encoder.encode(byteBuffer);
		System.out.println(result);
		String stringResult = new String(result.array(), StandardCharsets.UTF_8.toString());
		System.out.println(stringResult);
		assertThat(stringResult)
				.isEqualTo("QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVphYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3h5ejAxMjM0NTY3ODkrLw==");
	}

	@Test
	public void encodeToString() throws Exception {
		Base64.Encoder encoder = Base64.getEncoder();
		String value = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
		System.out.println(value);
		String result = encoder.encodeToString(value.getBytes(StandardCharsets.UTF_8.toString()));
		System.out.println(result);
		assertThat(result)
				.isEqualTo("QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVphYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3h5ejAxMjM0NTY3ODkrLw==");
	}

	@Test
	public void wrap() throws Exception {
		Path src = Paths.get("./", "README.md");
		System.out.println(src);
		Path dst = Paths.get("./", "README.log");
		System.out.println(dst);
		Base64.Encoder encoder = Base64.getEncoder();
		try (OutputStream output = Files.newOutputStream(dst)) {
			long result = Files.copy(src, encoder.wrap(output));
			System.out.println(result);
			// OutputStream encodedStrem = encoder.wrap(output);
		}
	}

	@Test
	public void Base64_encodeBase64() throws Exception {
		String value = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
		System.out.println(value);
		byte[] result = org.apache.commons.codec.binary.Base64
				.encodeBase64(value.getBytes(StandardCharsets.UTF_8.toString()));
		System.out.println(result);
		String stringResult = new String(result);
		System.out.println(stringResult);
		assertThat(stringResult)
				.isEqualTo("QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVphYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3h5ejAxMjM0NTY3ODkrLw==");
	}

	@Test
	public void Base64_encodeBase64String() throws Exception {
		String value = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
		System.out.println(value);
		String result = org.apache.commons.codec.binary.Base64
				.encodeBase64String(value.getBytes(StandardCharsets.UTF_8.toString()));
		System.out.println(result);
		assertThat(result)
				.isEqualTo("QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVphYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3h5ejAxMjM0NTY3ODkrLw==");
	}
}

心得分享

Base64 Encoder Functions in Java 工具類別提供了一套靜態方法取得基本編碼器，依照 RFC 4648 中指定的 Base64 字母表，輸出映射到一組字元A-Za-z0-9+/ ，不添加任何行分隔符號，熟悉 Base64 Encoder Methods in Java 這些方法的操作，提升開發效率，在應用上相當廣泛。

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