024

1. fetch更加简单的数据获取方式, 功能更加强大、更加灵活, 是基于Promise实现的。

2. fetch语法结构

fetch(url).then(fun1)
	.then(fun2)
	......
	.catch(fun)

3. 新建一个名为Promise的动态Web工程

3.1. 编写FetchAjax.java

package com.bjbs.fa;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class FetchAjax extends HttpServlet {
	private static final long serialVersionUID = 1L;

	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		String id = req.getParameter("id");
		resp.getWriter().write("Fetch Ajax get Request...   id = " + id);
	}
	
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		doGet(req, resp);
	}
}

3.2. 编写FetchAjaxPost.java

package com.bjbs.fa;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class FetchAjaxPost extends HttpServlet {
	private static final long serialVersionUID = 1L;

	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		String uname = req.getParameter("uname");
		String pwd = req.getParameter("pwd");
		resp.getWriter().write("Fetch Ajax post Request...   uname = " + uname + ", pwd = " + pwd);
	}
	
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		doGet(req, resp);
	}
}

3.3. 编写FetchAjaxPostJson.java

package com.bjbs.fa;

import java.io.BufferedReader;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class FetchAjaxPostJson extends HttpServlet {
	private static final long serialVersionUID = 1L;

	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		BufferedReader br = req.getReader();
		String result = "", rl = null;
		while((rl = br.readLine()) != null) {
			result += rl;
		}
		System.out.println("Fetch Ajax post Request Json Param...   result = " + result);
		
		String res = "{"code":1,"result":"success."}";
		resp.getWriter().write(res);
	}
	
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		doGet(req, resp);
	}
}

3.4. 修改web.xml

 3.5. 编写FetchGet.html

3.6. 编写FetchPost.html

3.7. 运行项目, 访问FetchGet.html

3.8. 运行项目, 访问FetchPost.html