java 原生http服务器 测试JS前端ajax访问实现跨域
后端
package Httpv3;import com.sun.net.httpserver.Headers;
import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpHandler;
import com.sun.net.httpserver.HttpServer;import java.io.IOException;
import java.io.OutputStream;
import java.net.InetSocketAddress;//来源
//https://blog.csdn.net/xietansheng/article/details/78704783//浏览器访问: http://localhost:8080/、http://localhost:8080/bb，输出: Hello World//浏览器访问: http://localhost:8080/aa、http://localhost:8080/aa/bb，输出: Hello World AA
// 版权声明：本文为博主原创文章，遵循 CC 4.0 BY-SA 版权协议，转载请附上原文出处链接和本声明。
//原文链接：https://blog.csdn.net/xietansheng/article/details/78704783public class Mainv2 {public static void main(String[] args) throws Exception {// 创建 http 服务器, 绑定本地 8080 端口HttpServer httpServer = HttpServer.create(new InetSocketAddress(8080), 0);// 创上下文监听, "/" 表示匹配所有 URI 请求httpServer.createContext("/", new HttpHandler() {@Overridepublic void handle(HttpExchange httpExchange) throws IOException {System.out.println("addr: " + httpExchange.getRemoteAddress() + // 客户端IP地址"; protocol: " + httpExchange.getProtocol() + // 请求协议: HTTP/1.1"; method: " + httpExchange.getRequestMethod() + // 请求方法: GET, POST 等"; URI: " + httpExchange.getRequestURI()); // 请求 URI// 获取请求头String userAgent = httpExchange.getRequestHeaders().getFirst("User-Agent");System.out.println("User-Agent: " + userAgent);// 响应内容
// byte[] respContents = "Hello World".getBytes("UTF-8");byte[] respContents = ("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\r\n"+ "<note>\r\n"+ " <to>Tove</to>\r\n"+ " <from>Jani</from>\r\n"+ " <heading>Reminder</heading>\r\n"+ " <body>Don't forget me this weekend!</body>\r\n"+ "</note>").getBytes("UTF-8");// 设置响应头// httpExchange.getResponseHeaders().add("Content-Type", "text/html; charset=UTF-8");
// 参数解释-允许跨域的各个参数
// https://developer.mozilla.org/zh-CN/docs/Web/HTTP/Headers/Access-Control-Request-HeadershttpExchange.getResponseHeaders().add("Access-Control-Allow-Origin","*");httpExchange.getResponseHeaders().add("Access-Control-Allow-Headers","*");httpExchange.getResponseHeaders().add("Access-Control-Allow-Methods","*");
// 允许接收各种消息头 对应前端 xhr.setRequestHeader('Content-Type', 'application/json');httpExchange.getResponseHeaders().add("Access-Control-Request-Headers","*");httpExchange.getResponseHeaders().add("Access-Control-Expose-Headers","*" );
// 对应前端特定消息头 xhr.setRequestHeader('Content-Type', 'application/json');httpExchange.getResponseHeaders().add("Content-Type", "text/html; charset=UTF-8");// 设置响应code和内容长度httpExchange.sendResponseHeaders(200, respContents.length);// 设置响应内容httpExchange.getResponseBody().write(respContents);// 测试数据String receive = httpExchange.getResponseBody().toString();System.out.println(receive);String receivev2 = httpExchange.getRequestBody().toString();System.out.println(receivev2);// 关闭处理器httpExchange.close();// 来源
// https://vimsky.com/examples/detail/java-method-com.sun.net.httpserver.HttpExchange.getResponseHeaders.html// Headers responseHeaders = httpExchange.getResponseHeaders();
// responseHeaders.add("Access-Control-Allow-Origin", "*");
// responseHeaders.add("Access-Control-Allow-Headers", "*");
// X-Custom-Header
// httpExchange.getResponseHeaders().add("Content-Type", "text/html; charset=UTF-8");
// httpExchange.getResponseHeaders().add("Access-Control-Allow-Methods","*");
// httpExchange.sendResponseHeaders(200, respContents.length);
// OutputStream outputStream = httpExchange.getResponseBody();
// outputStream.write(httpExchange.getResponseCode());
// outputStream.close();// byte[] respContentsv3 = "Hello World".getBytes("UTF-8");
// httpExchange.sendResponseHeaders(200, respContentsv3.length);
// httpExchange.getResponseBody().write(respContentsv3);// System.out.println("message"+httpExchange.getRequestBody().toString());// httpExchange.close();}});// 创建上下文监听, 处理 URI 以 "/aa" 开头的请求httpServer.createContext("/aa", new HttpHandler() {@Overridepublic void handle(HttpExchange httpExchange) throws IOException {byte[] respContents = "Hello World AA".getBytes("UTF-8");httpExchange.getResponseHeaders().add("Content-Type", "text/html; charset=UTF-8");httpExchange.sendResponseHeaders(200, respContents.length);httpExchange.getResponseBody().write(respContents);httpExchange.close();
// 来源
// https://vimsky.com/examples/detail/java-method-com.sun.net.httpserver.HttpExchange.getResponseHeaders.html// Add the header to avoid error:// “No 'Access-Control-Allow-Origin' header is present on the requested resource”
//
// Headers responseHeaders = httpExchange.getResponseHeaders();
// responseHeaders.add("Access-Control-Allow-Origin", "*");
// httpExchange.sendResponseHeaders(200, respContents.length);
//
// OutputStream outputStream = httpExchange.getResponseBody();
// outputStream.write(httpExchange.getResponseCode());
// outputStream.close();
// }});// 启动服务httpServer.start();}}前端
<!DOCTYPE html><!-- 来源 -->
<!-- https://cloud.tencent.com/developer/article/1705089 -->
<!-- https://geek-docs.com/ajax/ajax-questions/19_ajax_javascript_send_json_object_with_ajax.html -->
<!-- 配合java后端可以监听 -->
<!-- //原文链接：https://blog.csdn.net/xietansheng/article/details/78704783 --><html lang="en"><head><meta charset="UTF-8"><title>Title</title><script>function fun() {//发送异步请求//1、创建核心对象// var xmlhttp;// if (window.XMLHttpRequest) { //code for IE7+,Firefox,chrome,opera,safari// xmlhttp = new XMLHttpRequest();// } else { //code for IE6,IE5// xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");// }// //2、建立连接// /*// * 参数：请求方式、请求的url路径、同步或异步请求（true为异步）// * get方式：请求参数在url后面拼接，send方法为空；// * post方式：请求参数在send方法中定义。// * */// xmlhttp.open("GET", "ajaxServlet?username=Tim", true);// //3、发送请求// xmlhttp.send();// //4、接收及处理响应结果,当服务器响应成功了再获取// xmlhttp.onreadystatechange = function() { //当xmlhttp对象就绪状态改变时会触发事件// if (xmlhttp.readyState == 4 && xmlhttp.status == 200) { //请求已完成且响应就绪,响应状态码为200// alert(xmlhttp.responseText);// }// };// https://geek-docs.com/ajax/ajax-questions/19_ajax_javascript_send_json_object_with_ajax.html// 创建XMLHttpRequest对象var xhr = new XMLHttpRequest();// 设置请求类型和URL// xhr.open('POST', 'http://example.com/api', true);// xhr.open('POST', 'http://localhost:8080/aa', true);// xhr.open('POST', '/aa', true);// xhr.open('POST', 'http://localhost:8080/aa', true);xhr.open('POST', 'http://localhost:8080', true);// 设置请求头xhr.setRequestHeader('Content-Type', 'application/json');// xhr.setRequestHeader('X-Custom-Header', 'value');// xhr.setRequestHeader('Access-Control-Allow-Origin','*');console.log("请求头已设置\n");// 监听服务器响应// xhr.onreadystatechange = function() {// if (xhr.readyState === 4 && xhr.status === 200) {// // 从服务器获取响应// var response = JSON.parse(xhr.responseText);// console.log(response);// console.log(getAllResponseHeaders());// }// };// 构建JSON对象var data = {name: 'John',age: 25,email: 'john@example.com'};// 将JSON对象转换为字符串var jsonData = JSON.stringify(data);// 发送数据xhr.send(jsonData);// 注释掉就会爆 POST 错误提示//4、接收及处理响应结果,当服务器响应成功了再获取xhr.onreadystatechange = function() { //当xmlhttp对象就绪状态改变时会触发事件if (xhr.readyState == 4 && xhr.status == 200) { //请求已完成且响应就绪,响应状态码为200alert(xhr.responseText);console.log("检测的正确的返回\n");}else{console.log("检测到错误的返回\n");}console.log("检测到返回函数\n");};}</script></head><body><input type="button" value="发送异步请求" onclick="fun();"><input type="text"></body>
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