如何用Volley构建Map<String, List<>>结构并发送JSON格式POST请求

需要发送如下格式的JSON数据：

{"date": "2022-11-15",
    "number": "2222",
    "user": "Faisal",
    "report_note": "Test",
    "detail": [{
            "desc": "",
            "usable": 0,
            "condition": "GOOD",
            "numbering": "CRT-0002",
            "numbering_id": "2",
            "code": "F"
        },
        {
            "desc": "",
            "usable": 0,
            "condition": "GOOD",
            "numbering": "CRT-0001",
            "numbering_id": "1",
            "code": "F"
        }
    ]
}

需求：

• 能够接收服务器返回的JSON响应（已实现）
• 随请求向服务器发送上述格式的JSON数据

我编写了如下代码，但无法正确发送包含数组的JSON请求：

private void createPackagingReturn() {
    String url = "some/url";
    
    Map<String, String> params = new HashMap<>();
    params.put("date", date);
    params.put("number", number);
    params.put("user", name);
    params.put("report_note", report);
    params.put("detail", json);
    
    JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.POST, url,new JSONObject(params),
            new Response.Listener<JSONObject>() {
                @Override
                public void onResponse(JSONObject response) {
                    //Toast.makeText(getApplicationContext(),"Response :" + response.toString(), Toast.LENGTH_LONG).show();
                    title = "Information";
                    message = response.toString();
                    alertMessageError(title,message);
                    System.out.println(response);
                    try {
                        JSONObject jObj = new JSONObject(response.toString());
                        String status = jObj.getString("status");

                        if (status.equals("ok"))
                        {
                            //String message = jObj.getString("message");
                            title = "Success";
                            message = "ok";
                          
                            alertMessage(title,message);
                        }
                        else
                        {
                            title = "Error";
                            message = "error";
                            //alertMessageError(title,message);
                        }
                    } catch (JSONException e) {
                        e.printStackTrace();
                    }
                }
            }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            System.out.println(error.getLocalizedMessage());
        }
    }){
        
        @Override
        public Map<String,String> getHeaders() throws AuthFailureError {
            String bearer = "bearer ".concat(jwt);
            Map<String,String> headersSys = super.getHeaders();
            Map<String,String> headers = new HashMap<>();
            headersSys.remove("Authorization");
            headers.put("Accept", "application/json");
            headers.put("Authorization", bearer);
            headers.putAll(headersSys);
            return headers;
        }
    };
    RequestQueue requestQueue = Volley.newRequestQueue(getApplicationContext());
    requestQueue.add(jsonObjectRequest);
}

项目已引入GSON库，请帮忙修改代码，实现正确发送带上述JSON数据的JsonObjectRequest POST请求。

方法一：使用GSON序列化实体类（推荐） #

这种方式更易维护，避免手动拼接JSON出错。

1. 创建对应JSON结构的实体类

public class PackagingReturn {
    private String date;
    private String number;
    private String user;
    private String report_note;
    private List<Detail> detail;

    // 生成getter、setter方法，或用Lombok简化代码
    
    public static class Detail {
        private String desc;
        private int usable;
        private String condition;
        private String numbering;
        private String numbering_id;
        private String code;

        // 生成getter、setter方法
    }
}

2. 修改请求方法

private void createPackagingReturn() {
    String url = "some/url";

    // 组装数据到实体类
    PackagingReturn packagingReturn = new PackagingReturn();
    packagingReturn.setDate(date);
    packagingReturn.setNumber(number);
    packagingReturn.setUser(name);
    packagingReturn.setReport_note(report);

    List<PackagingReturn.Detail> detailList = new ArrayList<>();
    // 添加第一个detail数据
    PackagingReturn.Detail detail1 = new PackagingReturn.Detail();
    detail1.setDesc("");
    detail1.setUsable(0);
    detail1.setCondition("GOOD");
    detail1.setNumbering("CRT-0002");
    detail1.setNumbering_id("2");
    detail1.setCode("F");
    detailList.add(detail1);

    // 添加第二个detail数据
    PackagingReturn.Detail detail2 = new PackagingReturn.Detail();
    detail2.setDesc("");
    detail2.setUsable(0);
    detail2.setCondition("GOOD");
    detail2.setNumbering("CRT-0001");
    detail2.setNumbering_id("1");
    detail2.setCode("F");
    detailList.add(detail2);

    packagingReturn.setDetail(detailList);

    // 用GSON将实体类转为JSONObject
    Gson gson = new Gson();
    String jsonString = gson.toJson(packagingReturn);
    JSONObject requestBody = null;
    try {
        requestBody = new JSONObject(jsonString);
    } catch (JSONException e) {
        e.printStackTrace();
    }

    // 创建并发送请求
    JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.POST, url, requestBody,
            response -> {
                try {
                    String status = response.getString("status");
                    if ("ok".equals(status)) {
                        title = "Success";
                        message = "ok";
                        alertMessage(title, message);
                    } else {
                        title = "Error";
                        message = "error";
                        alertMessageError(title, message);
                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                    title = "Information";
                    message = response.toString();
                    alertMessageError(title, message);
                }
                System.out.println(response);
            },
            error -> System.out.println(error.getLocalizedMessage())
    ){
        @Override
        public Map<String,String> getHeaders() throws AuthFailureError {
            String bearer = "bearer ".concat(jwt);
            Map<String,String> headersSys = super.getHeaders();
            Map<String,String> headers = new HashMap<>();
            headersSys.remove("Authorization");
            headers.put("Accept", "application/json");
            headers.put("Authorization", bearer);
            headers.putAll(headersSys);
            return headers;
        }
    };

    RequestQueue requestQueue = Volley.newRequestQueue(getApplicationContext());
    requestQueue.add(jsonObjectRequest);
}

方法二：直接构建JSONObject（快速修改） #

如果不想创建实体类，可手动构建包含数组的请求体：

private void createPackagingReturn() {
    String url = "some/url";

    try {
        // 构建detail数组
        JSONArray detailArray = new JSONArray();
        
        JSONObject detail1 = new JSONObject();
        detail1.put("desc", "");
        detail1.put("usable", 0);
        detail1.put("condition", "GOOD");
        detail1.put("numbering", "CRT-0002");
        detail1.put("numbering_id", "2");
        detail1.put("code", "F");
        detailArray.put(detail1);

        JSONObject detail2 = new JSONObject();
        detail2.put("desc", "");
        detail2.put("usable", 0);
        detail2.put("condition", "GOOD");
        detail2.put("numbering", "CRT-0001");
        detail2.put("numbering_id", "1");
        detail2.put("code", "F");
        detailArray.put(detail2);

        // 构建完整请求体
        JSONObject requestBody = new JSONObject();
        requestBody.put("date", date);
        requestBody.put("number", number);
        requestBody.put("user", name);
        requestBody.put("report_note", report);
        requestBody.put("detail", detailArray);

        // 创建并发送请求
        JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.POST, url, requestBody,
                response -> {
                    try {
                        String status = response.getString("status");
                        if ("ok".equals(status)) {
                            title = "Success";
                            message = "ok";
                            alertMessage(title, message);
                        } else {
                            title = "Error";
                            message = "error";
                            alertMessageError(title, message);
                        }
                    } catch (JSONException e) {
                        e.printStackTrace();
                        title = "Information";
                        message = response.toString();
                        alertMessageError(title, message);
                    }
                    System.out.println(response);
                },
                error -> System.out.println(error.getLocalizedMessage())
        ){
            @Override
            public Map<String,String> getHeaders() throws AuthFailureError {
                String bearer = "bearer ".concat(jwt);
                Map<String,String> headersSys = super.getHeaders();
                Map<String,String> headers = new HashMap<>();
                headersSys.remove("Authorization");
                headers.put("Accept", "application/json");
                headers.put("Authorization", bearer);
                headers.putAll(headersSys);
                return headers;
            }
        };

        RequestQueue requestQueue = Volley.newRequestQueue(getApplicationContext());
        requestQueue.add(jsonObjectRequest);
    } catch (JSONException e) {
        e.printStackTrace();
    }
}

原代码问题说明 #

原代码用HashMap<String, String>存储参数时，detail被当作字符串传入，而非JSON数组，导致服务器收到的detail类型不符合预期。上述两种方法均可正确构建包含数组的JSON请求体，解决该问题。

内容的提问来源于stack exchange，提问作者KangIcal