问题场景:对于我写好的API接口,h5页面要通过Ajax请求接口获取数据。由于浏览器执行javascript脚本时,会检查这个脚本属于哪个页面,如果不是同源页面(所谓同源是指,域名,协议,端口均相同),就不会被执行,因此存在跨域问题。
解决流程:主要代码如下:
package com.tsingche.web.filter;
import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
/**
* 跨域过滤器
* Created by Administrator on 2017/3/23.
*/
@WebFilter(filterName="CorsFilter",urlPatterns="/*")
public class CorsFilter implements Filter {
public void init(FilterConfig filterConfig) throws ServletException {
System.out.println("*********************************过滤器初始化**************************");
}
public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
HttpServletResponse response = (HttpServletResponse) res;
response.setHeader("Access-Control-Allow-Origin", "*");
response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE");
response.setHeader("Access-Control-Max-Age", "3600");
response.setHeader("Access-Control-Allow-Headers", "x-requested-with");
System.out.println("*********************************过滤器被使用**************************");
chain.doFilter(req, res);
}
public void destroy() {
System.out.println("*********************************过滤器被销毁**************************");
}
}
package com.tsingche;
import com.tsingche.web.filter.CorsFilter;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.context.web.SpringBootServletInitializer;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
/**
* Created by Administrator on 2017/3/23.
*/
@Configuration//标明这个是SpringBoot的配置类,可以通过类配置代替原有的XML配置方式
@EnableAutoConfiguration //启动bean自动注入
public class StarsFilterConfiguration extends SpringBootServletInitializer {
/*FilterRegistrationBean 用来配置urlpattern 来确定哪些路径触发filter */
@Bean
public FilterRegistrationBean someFilterRegistration() {
FilterRegistrationBean registration = new FilterRegistrationBean();
registration.setFilter(AuthFilter());
registration.addUrlPatterns("/*");
registration.setOrder(1);
return registration;
}
/*使用annotation tag来取代*/
@Bean()
public CorsFilter AuthFilter() {
return new CorsFilter();
}
}
package com.tsingche.services;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
@SpringBootApplication
//@ServletComponentScan//这个就是扫描相应的Servlet包;
@ComponentScan(basePackages = {"com.tsingche"})
public class MejorServicesApplication extends WebMvcConfigurerAdapter {
public static void main(String[] args) {
SpringApplication.run(MejorServicesApplication.class, args);
}
}
前端页面如下
<script src="http://libs.baidu.com/jquery/1.8.3/jquery.min.js"></script>
参数名 参数值 单位 进气歧管压力 Kpa 节气门位置 % 点火提前角 ° 发动机负荷 % 剩余油量 % 车速 km/h 转速 Rpm 冷却液温度 ℃ 进气温度 ℃ 进气流量 g/s 故障码 个
由于对注解不熟悉,filter始终不生效,多番尝试终于开启了,还是要多关注注解背后的原理。