java - Servlet 返回 "到 AngularJS2 调用

Question

我正在使用 Angular2 对 servlet 进行 POST 调用。我现在必须使用 servlet。 Servlet 在响应中返回 JSON，但 Angular 将所有响应显示为失败，因为响应包含

"

在 JSON 响应中而不是“。我在控制台中看到了这一点:

xhrstatusText: {"status":"OK"}
replaced statusTest={"status":"OK"}

我不确定问题是否出在 servlet 或 Angular 调用上。

Servlet

public void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {    
    response.setContentType("application/json");
    response.setCharacterEncoding("UTF-8");
    JsonObject jsonObj = Json.createObjectBuilder().add("status", "OK").build();
    response.setStatus(HttpServletResponse.SC_OK, jsonObj.toString());
}

Angular2 POST 调用

makeFileRequest(params: Array<string>, files: Array<File>) {
    return new Promise((resolve, reject) => {
        var formData: any = new FormData();
        var xhr = new XMLHttpRequest();

        for(var i = 0; i < files.length; i++) {
            formData.append("uploads[]", files[i], files[i].name);
        }

        xhr.onreadystatechange = function () {
            if (xhr.readyState == 4) {
                // Contains &quot; instead of " in JSON.
                console.log('xhrstatusText: ' + xhr.statusText);
                // This fixes the JSON, but the response is already marked as failed.
                var statusTextJson = xhr.statusText.replace(/(&quot\;)/g,"\"");
                console.log('replaced statusTest=' + statusTextJson);

                if (xhr.status == 200) {
                    resolve(JSON.parse(xhr.response));
                } else {
                    reject(xhr.response);
                }
            }
        }

        xhr.open("POST", this.url, true);
        xhr.send(formData);
    });
}

!!!最终解决方案!!!

Servlet

public void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {    
    response.setContentType("application/json");
    response.setCharacterEncoding("UTF-8");
    response.setStatus(HttpServletResponse.SC_OK);
    JsonObject jsonObj = Json.createObjectBuilder().add("status", "OK").build();
    response.getWriter().println(jsonObj.toString());
}

Angular2 POST 调用

makeFileRequest(params: Array<string>, files: Array<File>) {
    return new Promise((resolve, reject) => {
        var formData: any = new FormData();
        var xhr = new XMLHttpRequest();

        for(var i = 0; i < files.length; i++) {
            formData.append("uploads[]", files[i], files[i].name);
        }

        xhr.onreadystatechange = function () {
            if (xhr.readyState == 4) {
                // {"status":"OK"}
                console.log('xhr.response: ' + xhr.response);

                if (xhr.status == 200) {
                    resolve(JSON.parse(xhr.response));
                } else {
                    reject(xhr.response);
                }
            }
        }

        xhr.open("POST", this.url, true);
        xhr.send(formData);
    });
}

Answer 1

根据 HttpServletResponse 的 javadoc ，由于这个原因(第二个参数的目的不明确)，setStatus(int, String) 方法实际上已被弃用。它并不是真正想要做你想做的事情。

相反，考虑简单地使用 setStatus(int) 方法设置状态并将 JsonObject 写入响应的打印编写器:

response.setStatus(HttpServletResponse.SC_OK);
response.getWriter().println(jsonObj.toString());