先來看一個例子，通過json傳值來獲取登入資訊，下圖的postman的演示：

注意：用的Post方式，Body中用raw選項，傳的是json資料

聯網框架okhttp+retrofit+Rxjava 處理如下：

在統一的介面檔案中的方法：
@POST("members/auth")
Observable<LoginBean> doLogin(@Body RequestBody requestBody);//這個RequestBody如何獲得

//這是{"username":"admin","password":"admin"}的bean檔案
LoginRequestBean loginRequestBean = new LoginRequestBean();  
loginRequestBean.setUsername("admin");  
loginRequestBean.setPassword("admin");  
Gson gson = new Gson();  
String toJson = gson.toJson(loginRequestBean);  
RequestBody requestBody = RequestBody.create(MediaType.parse("application/json; charset=utf-8"), toJson); 
 

public class LoginRequestBean {
    private String username;
    private String password;

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }
}