Java 如何在json post请求中发送字节数组？

how to send byte array in json post request?

提问by Sajeetharan

I have a wcf service which accepts byte[] serialData, now am developing a java client which needs to consume the same method.

我有一个接受的 wcf 服务 byte[] serialData，现在正在开发一个需要使用相同方法的 java 客户端。

When i sent bytearray to the service as a json post request , it is getting an exception as java.io.IOException: Server returned HTTP response code: 400

当我将 bytearray 作为 json post 请求发送到服务时，它出现异常 java.io.IOException: Server returned HTTP response code: 400

Here is my code:

这是我的代码：

wcf method:

wcf方法：

[OperationContract]
[WebInvoke(Method = "POST", ResponseFormat = WebMessageFormat.Json, UriTemplate = "saveSerialNumbers", BodyStyle = WebMessageBodyStyle.WrappedRequest)]
Dictionary<string, object> saveSerialNumbers(byte[] serialData);

Java Client:

Java客户端：

for (int i = 1; i < 100; i++) {      
                sb.append(String.valueOf(gen()));
    }
byte[]   bytesEncoded = Base64.encodeBase64(sb.toString().getBytes());
String json = "{\"serialDataByte\":\""+sb.toString()+"\"}";

This is my postrequest method:

这是我的 postrequest 方法：

public String getResultPOST(String jsonObject,String uri,String method) throws Exception{
        try {
            URL url = new URL(uri+method);
            System.out.println(url.toString());
            URLConnection connection = url.openConnection();
            connection.setDoOutput(true);
            connection.setRequestProperty("Content-Type", "application/json");
            connection.setConnectTimeout(5000);
            connection.setReadTimeout(5000);
            OutputStreamWriter out;
            try {
                out = new OutputStreamWriter(connection.getOutputStream());
                  out.write(jsonObject);
                    out.close();
            } catch (Exception e) {
                /
                // TODO Auto-generated catch block
                e.printStackTrace();
            }


            String line = "";
            StringBuilder builder = new StringBuilder();
            BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
            while ((line = in.readLine()) != null) {
                builder.append(line);
            }

            in.close();
            return builder.toString();
        } catch (Exception e) {
            throw e;
            //here is the exception
        }
    }

Here is my method call:

这是我的方法调用：

 String json = "{\"serialData\":\""+ new String(bytesEncoded)  +"\",\"guProductID\":\""+guProductID+"\",\"guStoreID\":\""+guStoreID+"\",\"securityToken\":\""+SecurityToken+"\"}";
 String serialContract  = serialClient.getResultPOST(json, "http://localhost:3361/EcoService.svc/Json/", "saveSerialNumbers");

采纳答案by Sajeetharan

Below, there's a simple working prototype to generate json from a string instance. Use this code snippet to update your client part. And it should work.

下面是一个从字符串实例生成 json 的简单工作原型。使用此代码片段更新您的客户端部分。它应该工作。

import java.util.Base64;

public class Test {

    public static void main(String[] args) {

        StringBuilder sb = new StringBuilder();

        // composing string to be encoded
        sb.append("Part 1 of some text to be encoded to base64 format\n");
        sb.append("Part 2 of some text to be encoded to base64 format\n");
        sb.append("Part 3 of some text to be encoded to base64 format");


        // getting base64 encoded string bytes
        byte[]   bytesEncoded = Base64.getEncoder().encode(sb.toString().getBytes());

        // composing json
        String json = "{\"serialDataByte\":\""+ new String(bytesEncoded) +"\"}";        

        System.out.println(json);

    }
}

UPDATE:

更新：

The code uses Java 8 SDK. If you are using pre-Java8 version, then consider Apache Commons Codecfor this task.

该代码使用 Java 8 SDK。如果您使用的是 Java8 之前的版本，请考虑使用Apache Commons Codec来完成此任务。

Below there's a sample code, that uses Apache Commons Codec for Base64 encoding (please note that import directive has been changed):

下面是一个示例代码，它使用 Apache Commons Codec 进行 Base64 编码（请注意导入指令已更改）：

import org.apache.commons.codec.binary.Base64;

public class Test {

    public static void main(String[] args) {

        StringBuilder sb = new StringBuilder();

        // composing string to be encoded
        sb.append("Part 1 of some text to be encoded to base64 format\n");
        sb.append("Part 2 of some text to be encoded to base64 format\n");
        sb.append("Part 3 of some text to be encoded to base64 format");


        // getting base64 encoded string bytes
        byte[] bytesEncoded =  Base64.encodeBase64(sb.toString().getBytes());

        // composing json
        String json = "{\"serialDataByte\":\""+ new String(bytesEncoded) +"\"}";        

        System.out.println(json);

    }
}

UPDATE 2:

更新 2：

Upon sending POST requests make sure that you have marked your request as a POST request. Do not forget this line of code, before making the request:

发送 POST 请求后，请确保您已将请求标记为 POST 请求。在发出请求之前，不要忘记这行代码：

connection.setRequestMethod("POST");

and use HttpURLConnection instead of URLConnection:

并使用 HttpURLConnection 而不是 URLConnection：

import java.net.HttpURLConnection;