spring-boot之（5） web 静态资源

　　spring-boot加入web的依赖后，项目很容易实现返回json的HTTP接口，所以如果是基于Restful接口的请求，无须多说，Maven加入以下依赖即可。

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

• 静态资源目录

　　传统的项目都没有做前后端分离，所以静态资源是放在Web服务器里面的。spring-boot提供配置文件设置静态资源目录，也提供了默认的方式设定静态资源目录。

1. spring-boot默认按照目录名（目录名为/static、/public、/resources或者/META-INF/resources）来设置静态资源目录，也就是资源目录中含有前面所述目录的话，就认为该目录是资源根目录

2. 通过application.properties或者application.yml设置spring.mvc.static-path-pattern或者spring.resources.static-locations来设置资源目录

spring.mvc.static-path-pattern=/resources/**
spring.resources.static-locations=

 

• 错误异常公共代码处理

　　错误的公共处理分两种方式一种是继承BasicErrorController，另一种是通过@ControllerAdvice。

　　ControllerAdvice注解实现如下，官网例子

@ControllerAdvice(basePackageClasses = FooController.class)
public class FooControllerAdvice extends ResponseEntityExceptionHandler {

    @ExceptionHandler(YourException.class)
    @ResponseBody
    ResponseEntity<?> handleControllerException(HttpServletRequest request, Throwable ex) {
        HttpStatus status = getStatus(request);
        return new ResponseEntity<>(new CustomErrorType(status.value(), ex.getMessage()), status);
    }

    private HttpStatus getStatus(HttpServletRequest request) {
        Integer statusCode = (Integer) request.getAttribute("javax.servlet.error.status_code");
        if (statusCode == null) {
            return HttpStatus.INTERNAL_SERVER_ERROR;
        }
        return HttpStatus.valueOf(statusCode);
    }

}

　　继承BasicErrorController重写方法即可（注意produces）

@Controller
@RequestMapping({"${server.error.path:${error.path:/error}}"})
public class BasicErrorController extends AbstractErrorController {
    private final ErrorProperties errorProperties;

    public BasicErrorController(ErrorAttributes errorAttributes, ErrorProperties errorProperties) {
        this(errorAttributes, errorProperties, Collections.emptyList());
    }

    public BasicErrorController(ErrorAttributes errorAttributes, ErrorProperties errorProperties, List<ErrorViewResolver> errorViewResolvers) {
        super(errorAttributes, errorViewResolvers);
        Assert.notNull(errorProperties, "ErrorProperties must not be null");
        this.errorProperties = errorProperties;
    }

    public String getErrorPath() {
        return this.errorProperties.getPath();
    }

    @RequestMapping(
        produces = {"text/html"}
    )
    public ModelAndView errorHtml(HttpServletRequest request, HttpServletResponse response) {
        HttpStatus status = this.getStatus(request);
        Map model = Collections.unmodifiableMap(this.getErrorAttributes(request, this.isIncludeStackTrace(request, MediaType.TEXT_HTML)));
        response.setStatus(status.value());
        ModelAndView modelAndView = this.resolveErrorView(request, response, status, model);
        return modelAndView == null?new ModelAndView("error", model):modelAndView;
    }

    @RequestMapping
    @ResponseBody
    public ResponseEntity<Map<String, Object>> error(HttpServletRequest request) {
        Map body = this.getErrorAttributes(request, this.isIncludeStackTrace(request, MediaType.ALL));
        HttpStatus status = this.getStatus(request);
        return new ResponseEntity(body, status);
    }

    protected boolean isIncludeStackTrace(HttpServletRequest request, MediaType produces) {
        IncludeStacktrace include = this.getErrorProperties().getIncludeStacktrace();
        return include == IncludeStacktrace.ALWAYS?true:(include == IncludeStacktrace.ON_TRACE_PARAM?this.getTraceParameter(request):false);
    }

    protected ErrorProperties getErrorProperties() {
        return this.errorProperties;
    }
}

•  参考资料

https://docs.spring.io/spring-boot/docs/current-SNAPSHOT/reference/htmlsingle/#boot-features-developing-web-applications