从 java 脚本调用 rest api 邮政服务引发错误

Question

在控制台中从 java 脚本调用邮政服务时，我收到以下错误

加载资源失败：服务器响应状态为 415 ()

在我的后端 java eclipse ide 得到以下错误

不支持内容类型 'text/plain;charset=UTF-8'

如何解决此错误

提前致谢

HTML 代码：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <link rel="stylesheet" href="css/index.css" />
    <title>Document</title>
</head>
<body>
    <div>
        <h1 class="myclass">HELLO!WELCOME</h1>
    </div>
    <div>
        <form id="loginform" method="post">
            <div class="form-group">
                <input type="number" class="form-control" id="inputphone" placeholder="Enter phone number">
            </div>
            <div class="form-group">
                <input type="password" class="form-control" id="inputpassword" placeholder="Enter Password">
            </div>
            <div class="forgot-password">
                <a href="">forgot password</a>
            </div>
           <input type="submit"value="Login"/>
        </form>
    </div>
    <script src="js/index.js"> </script>    
</body>
</html> 

java 脚本代码：

var form = document.getElementById('loginform')

form.addEventListener('submit', function (e) {

    e.preventDefault();

    var inputphoneno = document.getElementById("inputphone").value;
    var inputpassword = document.getElementById("inputpassword").value;
    
    const jdata = {
        "phonenumber":inputphoneno,
        "password":inputpassword
      };

    fetch('http://localhost:8080/myurl/', {
        method: 'POST',
        body: JSON.stringify({jdata}),
        headers: {
            'Content-Type': 'application/json; charset=UTF-8',
        },
        mode: "no-cors"
    })
        .then(function (response) {
            //return response.json();
            console.log(response)
        })
        .then(function (data) {
            console.log(data)
        })

})