java图片编码解码
目录
图片编码
获取图片的二进制byte[]数组，然后base64编码，这样是为了给前端返回展示。
BASE64Encoder encoder = new sun.misc.BASE64Encoder();
File f = new File("F:\\Temp\\test.png");
BufferedImage bi;
bi = ImageIO.read(f);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ImageIO.write(bi, "png", baos);
byte[] bytes = baos.toByteArray();
String base64Str = encoder.encodeBuffer(bytes).trim();如下就是base64Str的部分样子，
| /9j/4AAQSkZJRgABAAAAAQABAAD/4QBYRXhpZgAATU0AKgAAAAgAAgESAAMAAAABAAEAAIdpAAQAAAABAAAAJgAAAAAAA6ABAAMAAAAB//8AAKACAAQAAAABAAAAZKADAAQAAAABAAAAjAAAAAD//gAgSnBlZyBDb2RlYyB8IGZsdXhjYXBhY2l0eS5uZXQg/9sAhAADAgIDAgIDAwMDBAMDBAUIBQUEBAUKBwcGCAwKDAwLCgsLDQ4SEA0OEQ4LCxAWEBETFBUVFQwPFxgWFBgSFBUUAQMEBAUEBQkFBQkUDQsNFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBT/wAARCACMAGQDAREAAhEBAxEB/8QBogAAAQUBAQEBAQEAAAAAAAAAAAECAwQFBgcICQoLEAACAQMDAgQDBQUEBAAAAX0BAgMABBEFEiExQQYTUWEHInEUMoGRoQgjQrHBFVLR8CQzYnKCCQoWFxgZGiUmJygpKjQ1Njc4OTpDREVGR0hJSlNUVVZXWFlaY2RlZmdoaWpzdHV2d3h5eoOEhYaHiImKkpOUlZaXmJmaoqOkpaanqKmqsrO0tba3uLm6wsPExcbHyMnK0tPU1dbX2Nna4eLj5OXm5+jp6vHy8/T19vf4+foBAAMBAQEBAQEBAQEAAAAAAAABAgMEBQYHCAkKCxEAAgECBAQDBAcFBAQAAQJ3AAECAxEEBSExBhJBUQdhcRMiMoEIFEKRobHBCSMzUvAVYnLRChYkNOEl8RcYGRomJygpKjU2Nzg5OkNERUZHSElKU1RVVldYWVpjZGVmZ2hpanN0dXZ3eHl6goOEhYaHiImKkpOUlZaXmJmaoqOkpaanqKmqsrO0tba3uLm6wsPExcbHyMnK0tPU1dbX2Nna4uPk5ebn6Onq8vP09fb3+Pn6/9oADAMBAAIRAxEAPwD7F8xcdetdBziFuTmquA0txQA3fkUDKOoarDZW7TSHEaYdiSBhc8nk+g7A9KSQjwT4q/te+E/ACzWq6iLu73SxeXCd7ADGSwHKnOQM4z2GKxlUiti+Vvc8z8Lf8FH9Gm1eyh1rSroWJys81qoLq3ZgjEcZBzyeCPTBlVS+Tsz7G8IeL9I8deH7LXNCv4tS0u7TfFcwHKt2I5wQQcggjIIINdCd9UZNW3N5WGeKp6gS5x+NLYNx2/NO4hwIHapbuaJWPnz9oxs+K9N/68h/6MesKhR7F5px0rexHKAnIPNNq4uVjhMD3/Ckk0K1hkzAI5eQIgBJJwAB+NO4j8+v20/2jpbzUpPCGiT7Qp3XlwAMrwMRrjlG67j1OBglSM8tWb2RrBWd2fHEn2iaFrp3Zkd9gY9cjk/zFc6NW2U4LkxuQHxjkq4GD+Na8uhJ73+yr+0pe/Anxxb/AGmeWfwhfyBNUsmZiI8gAXCD/nogwePvqu0/wsqi3B+QP3kfrXZ3kN7bQXVvNHcW80ayxywsGR0YZVgRwQQQQa7UznLHmE+tUBIr4ps0VhfNwOPyqeUqx4B+0Kd/irTs/wDPkP8A0N6yqLYdj18vjNb2CxHJJxxxTCxF5uD7UCbVjkPjD43g8GfDHxHq9xLsFvZSsuGCkttOACfU4H41EnypszWrSPxz1nV73xXq93ql25aa4kaV2ycDJzgZ9OB7D8K82/U262NTQdIi1Xw7cxtDiUOXjnLnaeOQeMdAe/61nJ2kbRi5ROYmtHs5ChGBk8E10qSMWmmRWzESeWxChgQBUyJP1E/4J9fGY+OvhdN4U1Gd21XwvshiZ8nzLN8+Tz6oQ6egVY/WumjK6syZLqfVYcH3zW5mSK1JFRdnccpNU3Y1ueC/tB8eKtP/AOvIf+hvXPUYXPXSwJzXSMjY84oEyvJgDrQYnyT/AMFEPGMul/Dbw/4 |
前端展示
返回了base64Str后，需要在前端展示，下面是vue的代码，获取后台的base64Str，直接前端展示。
let base64Str = "data:image/png;base64,"+res.data;
this.imgSrc = base64Str;
<image :src="imgSrc" style="border-radius:50%;width:400rpx;height:400rpx"></image>图片解码
解码并写回到系统盘。
BASE64Decoder decoder = new sun.misc.BASE64Decoder();
byte[] bytes1 = decoder.decodeBuffer(base64String);
ByteArrayInputStream bais = new ByteArrayInputStream(bytes1);
BufferedImage bi1 = ImageIO.read(bais);
File w2 = new File("F:\\Temp\\test2.png");//可以是jpg,png,gif格式
ImageIO.write(bi1, "png", w2);//不管输出什么格式图片，此处不需改动
其他
其实如果光光是图片展示的话，还可以使用HttpServletResponse流直接写出byte[]数组。
图片的byte数组其实就 [102,103,104,22,-2,332......] 这样的格式。
@RequestMapping("getPhoto")
public byte[] getPhoto(HttpServletResponse response){
byte[] bytes = //图片的二进制流数据
ServletOutputStream os = response.getOutputStream();
os.write(bytes);
os.flush();
}
浏览器直接访问就能展示图片，所以直接在image标签中加上这个url就行。
<image src="http://192.168.3.92:8088/api/photo/getPhoto"></image>
