跨域问题解决方案

五种网站跨域解决方案

1. 使用jsonp解决网站跨域只能支持get 不支持post

2.使用HttpClient内部转发效率低发送两次请求
3.使用设置响应头允许跨域
4.基于Nginx搭建企业级API接口网关保证域名和端口一直以项目区分反向代理到真实服务器地址
5.使用Zuul搭建微服务API接口网关

使用设置响应头允许跨域:

在B项目中添加：

response.setHeader("Access-Control-Allow-Origin", "*");

package com.toov5.controller;

import java.util.HashMap;
import java.util.Map;

import javax.servlet.http.HttpServletResponse;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@SpringBootApplication
public class BIndexController {
    @RequestMapping("/getBInfo")
   public Map<String, Object> getBInfo(HttpServletResponse response){
        //告诉浏览器 允许跨域   这段代码应该放在过滤器里面的
        response.setHeader("Access-Control-Allow-Origin", "*");  //*代表所有 可以a.toov5.com专门的
       //提供给Ajax嗲用
       Map<String,Object> result = new HashMap<String, Object>();
       result.put("code", 200);
       result.put("msg", "登录成功");
       return result;
   }
    
    public static void main(String[] args) {
        SpringApplication.run(BIndexController.class, args);
        
    }
}

JSONP解决方案：

<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>

<script type="text/javascript"
	src="http://code.jquery.com/jquery-1.8.0.min.js"></script>
<script type="text/javascript">
	$(document).ready(function() {
		$.ajax({
			type : "POST",
			async : false,
			url : "http://b.toov5.com:8081/getBInfo",
			dataType : "jsonp",
			jsonp : "jsonpCallback",//服务端用于接收callback调用的function名的参数 
			success : function(data) {
				alert(data["code"]);   //获取到code
			},
			error : function() {
				alert('fail');
			}
		});

	});
</script>
</head>
<body>我是A项目 正在调用B项目
</body>
</html>

　　首先该成JSONP的形式

dataType : "jsonp",
jsonp : "jsonpCallback",//服务端用于接收callback调用的function名的参数

访问：（生成的随机数）

注意不支持post请求！

HttpClient方案转发：

相当于发送两次请求

隐藏了真实地址 Nginx反向代理类似

同时需要@ResponseBody哦因为返回json格式

修改前段访问的接口保持一致：

$(document).ready(function() {
		$.ajax({
			type : "POST",
			async : false,
			url : "http://a.toov5.com:8080/forwardB",
			dataType : "json",
			success : function(data) {
				alert(data["code"]);   //获取到code
			},
			error : function() {
				alert('fail');
			}
		});

	});

HttpClient：

package com.toov5.controller;

import java.io.IOException;

import org.apache.http.HttpEntity;
import org.apache.http.HttpStatus;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.alibaba.fastjson.JSONObject;

public class HttpClientUtils {
    private static Logger logger = LoggerFactory.getLogger(HttpClientUtils.class); // 日志记录

    private static RequestConfig requestConfig = null;

    static {
        // 设置请求和传输超时时间
        requestConfig = RequestConfig.custom().setSocketTimeout(2000).setConnectTimeout(2000).build();
    }

    /**
     * post请求传输json参数
     * 
     * @param url
     *            url地址
     * @param json
     *            参数
     * @return
     */
    public static JSONObject httpPost(String url, JSONObject jsonParam) {
        // post请求返回结果
        CloseableHttpClient httpClient = HttpClients.createDefault();
        JSONObject jsonResult = null;
        HttpPost httpPost = new HttpPost(url);
        // 设置请求和传输超时时间
        httpPost.setConfig(requestConfig);
        try {
            if (null != jsonParam) {
                // 解决中文乱码问题
                StringEntity entity = new StringEntity(jsonParam.toString(), "utf-8");
                entity.setContentEncoding("UTF-8");
                entity.setContentType("application/json");
                httpPost.setEntity(entity);
            }
            CloseableHttpResponse result = httpClient.execute(httpPost);
            // 请求发送成功，并得到响应
            if (result.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
                String str = "";
                try {
                    // 读取服务器返回过来的json字符串数据
                    str = EntityUtils.toString(result.getEntity(), "utf-8");
                    // 把json字符串转换成json对象
                    jsonResult = JSONObject.parseObject(str);
                } catch (Exception e) {
                    logger.error("post请求提交失败:" + url, e);
                }
            }
        } catch (IOException e) {
            logger.error("post请求提交失败:" + url, e);
        } finally {
            httpPost.releaseConnection();
        }
        return jsonResult;
    }

    /**
     * post请求传输String参数 例如：name=Jack&sex=1&type=2
     * Content-type:application/x-www-form-urlencoded
     * 
     * @param url
     *            url地址
     * @param strParam
     *            参数
     * @return
     */
    public static JSONObject httpPost(String url, String strParam) {
        // post请求返回结果
        CloseableHttpClient httpClient = HttpClients.createDefault();
        JSONObject jsonResult = null;
        HttpPost httpPost = new HttpPost(url);
        httpPost.setConfig(requestConfig);
        try {
            if (null != strParam) {
                // 解决中文乱码问题
                StringEntity entity = new StringEntity(strParam, "utf-8");
                entity.setContentEncoding("UTF-8");
                entity.setContentType("application/x-www-form-urlencoded");
                httpPost.setEntity(entity);
            }
            CloseableHttpResponse result = httpClient.execute(httpPost);
            // 请求发送成功，并得到响应
            if (result.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
                String str = "";
                try {
                    // 读取服务器返回过来的json字符串数据
                    str = EntityUtils.toString(result.getEntity(), "utf-8");
                    // 把json字符串转换成json对象
                    jsonResult = JSONObject.parseObject(str);
                } catch (Exception e) {
                    logger.error("post请求提交失败:" + url, e);
                }
            }
        } catch (IOException e) {
            logger.error("post请求提交失败:" + url, e);
        } finally {
            httpPost.releaseConnection();
        }
        return jsonResult;
    }

    /**
     * 发送get请求
     * 
     * @param url
     *            路径
     * @return
     */
    public static JSONObject httpGet(String url) {
        // get请求返回结果
        JSONObject jsonResult = null;
        CloseableHttpClient client = HttpClients.createDefault();
        // 发送get请求
        HttpGet request = new HttpGet(url);
        request.setConfig(requestConfig);
        try {
            CloseableHttpResponse response = client.execute(request);

            // 请求发送成功，并得到响应
            if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
                // 读取服务器返回过来的json字符串数据
                HttpEntity entity = response.getEntity();
                String strResult = EntityUtils.toString(entity, "utf-8");
                // 把json字符串转换成json对象
                jsonResult = JSONObject.parseObject(strResult);
            } else {
                logger.error("get请求提交失败:" + url);
            }
        } catch (IOException e) {
            logger.error("get请求提交失败:" + url, e);
        } finally {
            request.releaseConnection();
        }
        return jsonResult;
    }

}

Controller：

package com.toov5.controller;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import com.alibaba.fastjson.JSONObject;

@Controller
@SpringBootApplication
public class AIndexController {
    
 @RequestMapping("/aIndexJsp")
  public String  AIndexJsp() {
      return "aIndex";
  }
    //使用httpClient进行访问b接口
    @RequestMapping("/forwardB")
    @ResponseBody   //这里一定要为 json形式！！！  jsp中的ajax访问的路径
    public JSONObject forwardB() {
        JSONObject result = HttpClientUtils.httpGet("http://b.toov5.com:8081/getBInfo");
        return result;
    }
    
    
    public static void main(String[] args) {
        SpringApplication.run(AIndexController.class, args);
    }
    
    
}

B的controller：

package com.toov5.controller;

import java.util.HashMap;
import java.util.Map;

import javax.servlet.http.HttpServletResponse;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@SpringBootApplication
public class BIndexController {
    @RequestMapping("/getBInfo")
   public Map<String, Object> getBInfo(HttpServletResponse response){
        //告诉浏览器 允许跨域   这段代码应该放在过滤器里面的
//        response.setHeader("Access-Control-Allow-Origin", "*");  //*代表所有 可以a.toov5.com专门的
       //提供给Ajax嗲用
       Map<String,Object> result = new HashMap<String, Object>();
       result.put("code", 200);
       result.put("msg", "登录成功");
       return result;
   }
    

    
    public static void main(String[] args) {
        SpringApplication.run(BIndexController.class, args);
        
    }
}

Nginx 方案：

api.toov5.com/a

api.toov5.com/b

通过Nginx 转发到不同的项目

Zuul方案：

类似Nginx 修改Zuul的配置yml

不管访问A项目还是B项目首先保证域名端口号统一

请求先到Nginx 判断域名相同项目名字不同转发到某个项目