如何在Java spring rest 返回一个数组对象，而不是字符串；

本文链接：https://blog.youkuaiyun.com/yuzhenhaocugb/article/details/121874274

本文介绍如何在Spring MVC中处理Base64编码转换，通过修改返回类型并使用Gson库，将对象中的字节数组转换为JSON数组格式。

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在spring mvc会将对象种的字节数组成员转换成base64编码的字符传格式，前台接收到数据后要进行base64界面才能恢复成原字节数组，网上有很多解决方案通过都修改produces = {"text/plain", "application/json"}为多媒体格式来解决；

public class ResponseByteArray {
    private String fileName;
    private byte[] file;
    public String getFileName() {
        return fileName;
    }
    public void setFileName(String fileName) {
        this.fileName = fileName;
    }
    public byte[] getFile() {
        return file;
    }
    public void setFile(byte[] file) {
        this.file = file;
    }   
}

@RequestMapping(value = "/getDataByte", method = RequestMethod.GET)
    public ResponseEntity<?> uploadUImageGet() throws IOException {
        ResponseByteArray response = new ResponseByteArray();
        File fileImage = new File("D://images//download1.jpg");
        byte[] fileContent = Files.readAllBytes(fileImage.toPath());
        response.setFileName("testFile.jpg");
        response.setFile(fileContent);
        return new ResponseEntity<ResponseByteArray>(response, HttpStatus.OK);
    }
}

{ 
"fileName": "testFile.jpg", 
"file":"/9j/4AAQSkZJRgABAQAAAQABAAD/2wCEAAkGBxIQEg8PEhIPFRIPDw8QEA8QDw8PEBAPFREWFhUVFRUYHSggGBolHRUVITEhJSkrLi4uFx8zODMsNygtLisBCgoKDg0NFQ8PFSsdFR0tLS0tKysrKy0tKy0tNy03LS0rKy0tLSsrKzc3LS0rLSsrKy0rKzctLTcrLSstNy0tK//AABEIAQMAwgMBIgACEQEDEQH/xAAbAAABBQEBAAAAAAAAAAAAAAADAAECBAUGB//EAD8QAAIBAgMFBQUGBQIHAQAAAAECAAMRBCExBRJBUWEGMnGBkRMiUqHRFGJyscHwQpKisuEjkxUXM3OC0vEH/8QAGQEBAQEBAQEAAAAAAAAAAAAAAAECAwUE/8QAIBEBAQEAAwADAAMBAAAAAAAAABEBAgMSITFBEyJRB ... 
}

但是如果想将上边的json数据返回值变成如下格式该怎么办呢？

{ 
"fileName": "testFile.jpg", 
"file":[23,4,5,6,3,,7,45,6,5,34....]
}

其实对原方法稍作修改即可，这里用到了gson，可以在方法种显示的将对象转换为json字符串，不用spring MVC默认的转换方式即可。


@RequestMapping(value = "/getDataByte", method = RequestMethod.GET)
public String uploadUImageGet() throws IOException {
   。。。

   return new Gson().toJson(responseDto);
}