如何将multipartfile文件转换成base64编码

Question

如题所述

Answer 1

例子说明一切
先写单元测试吧：单元测试的代码如下：
package test.com.cs;

import com.cs.Base64Convert;
import junit.framework.TestCase;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.logging.Logger;

public class TestBase64Convert extends TestCase {
Base64Convert baseCov = null;

public TestBase64Convert(String s) {
super(s);
}

protected void setUp() throws Exception {
baseCov = new Base64Convert();
}

protected void tearDown() throws Exception {
super.tearDown();
}

public void testIoToBase64() {
try {
String strBase64 = baseCov.ioToBase64(); //将 io 转换为 base64编码
System.out.println(">>> "+strBase64);
baseCov.base64ToIo(strBase64); //将 base64编码转换为 io 文件流，生成一幅新图片
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}

------------------------------------
package com.cs;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

import java.io.*;

public class Base64Convert {
BASE64Decoder decoder = new BASE64Decoder();

public String ioToBase64() throws IOException {
String fileName = "d:/gril.gif"; //源文件
String strBase64 = null;
try {
InputStream in = new FileInputStream(fileName);
// in.available()返回文件的字节长度
byte[] bytes = new byte[in.available()];
// 将文件中的内容读入到数组中
in.read(bytes);
strBase64 = new BASE64Encoder().encode(bytes); //将字节流数组转换为字符串
in.close();
} catch (FileNotFoundException fe) {
fe.printStackTrace();
} catch (IOException ioe) {
ioe.printStackTrace();
}
return strBase64;
}

public void base64ToIo(String strBase64) throws IOException {
String string = strBase64;
String fileName = "d:/gril2.gif"; //生成的新文件
try {
// 解码，然后将字节转换为文件
byte[] bytes = new BASE64Decoder().decodeBuffer(string); //将字符串转换为byte数组
ByteArrayInputStream in = new ByteArrayInputStream(bytes);
byte[] buffer = new byte[1024];
FileOutputStream out = new FileOutputStream(fileName);
int bytesum = 0;
int byteread = 0;
while ((byteread = in.read(buffer)) != -1) {
bytesum += byteread;
out.write(buffer, 0, byteread); //文件写操作
}
} catch (IOException ioe) {
ioe.printStackTrace();
}
}
}