我thread.sleep()在下面的代码中添加了硬代码等待。如何使用显式等待。我想等到“用户名”
WebElement出现。我的程序运行正常。我已经写了测试用例。

package com.pol.zoho.PageObjects;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.support.FindBy;
import org.openqa.selenium.support.PageFactory;
import org.openqa.selenium.support.ui.WebDriverWait;

public class ZohoLoginPage {

WebDriver driver;
public ZohoLoginPage(WebDriver driver)
{
    PageFactory.initElements(driver,this);
}

@FindBy(xpath=".//*[@id='lid']")
public WebElement email;

@FindBy(xpath=".//*[@id='pwd']")
public WebElement password;

@FindBy(xpath="//*[@id='signin_submit']")
public WebElement signin;

public void doLogin(String username,String userpassword)
{
    try {
        Thread.sleep(3000);
    } catch (InterruptedException e) {
        e.printStackTrace();
    }

    email.sendKeys(username);
    password.sendKeys(userpassword);
    signin.click();
}

}

# -*- coding: utf-8 -*-
''''''
Created on 2018-11-4
@author: 丹姐
Project:UI页面公共类
''''''

from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
import selenium.common.exceptions
from selenium.webdriver.common.by import By



#定义页面基类
class BasePage(object):
    #初始化
    def __init__(self,driver):
        self.driver=driver

    # 重写元素定位方法
    def find_element(self,timeout,poll_frequency,type,*loc):
        element=WebDriverWait(self.driver, timeout, poll_frequency).until(
            EC.presence_of_element_located((type,*loc)))
        return element


    # 重写定义send_keys方法
    def send_keys(self,timeout,poll_frequency,type,loc,value):
        try:
                self.find_element(timeout,poll_frequency,type,loc).clear()
                return self.find_element(timeout,poll_frequency,type,loc).send_keys(value)
        except AttributeError:
            print("%s 页面中未能找到 %s 元素" % (self,loc))

    # 重写定义click方法
    def click(self,timeout,poll_frequency,type,*loc):
        return self.find_element(timeout,poll_frequency,type,*loc).click()

    # 重写多元素定位方法
    def find_elements(self,timeout,poll_frequency,index,type,*loc ):
        elements = WebDriverWait(self.driver, timeout, poll_frequency).until(
            EC.presence_of_all_elements_located((type, *loc)))
        return elements[index]

# coding=utf-8
''''''
Created on 2018-11-4
@author: 丹姐
Project:登录页面
''''''
from src.common.BasePage import BasePage
from selenium.webdriver.common.by import By


# 定义登录页面类，父类是BasePage


class Login(BasePage):
    etUser_loc = "com.baidu.baidu:id/et_name"
    etPws_loc = "com.baidu.baidu:id/et_pass"
    btnLogin_loc = "com.baidu.baidu:id/rt_login"


    def login_in(self, username, password):
       print(u''输入用户名'', username)
        self.send_keys(10, 0.1, By.ID, self.etUser_loc, username)
        print(u''输入密码'', password)
        self.send_keys(10, 0.1, By.ID, self.etPws_loc, password)
        print(u''点击登录按钮'')
        self.click(20, 0.1, By.ID, self.btnLogin_loc)

    

# coding=utf-8
''''''
Created on 2018-12-24
@author: 丹姐
Project:登录测试用例
''''''
import unittest
from config import DriverConfigure
from src.pages.Login import Login



class Login(unittest.TestCase):
    @classmethod
    def setUpClass(cls):
        driver = DriverConfigure.get_driver()
        cls.driver = driver


    def setUp(self):
        self.login_page = Login(self.driver)


    def test_login(self):
        # 登录
        self.login_page.login_in("zhanghao", "123456")


    def tearDown(self):
        pass

    @classmethod
    def tearDownClass(cls):
        cls.driver.quit()

if __name__ =="__main__":
 unittest.main()

解决方法

ObjectMapper mapper = new ObjectMapper();
ObjectNode objectNode = mapper.createObjectNode();

ObjectNode objectNode = JsonNodeFactory.instance.objectNode();