SpringMVC自定义兼容性HandlerMapping
SpringMVC自定义兼容性HandlerMapping
写在前面
看到这篇博客时，默认你知道Spring MVC中HandlerMapping的作用，及前台请求到响应的的流转。
感谢网上其他大佬博客给我的借鉴，博客地址这里忘记了。
大家可以直接点击右上角进入我的SpringBoot项目查看源码，有用的话帮我点亮下呗。
自定义Handler
我有时候会考虑是否可以自定义HandlerMapping，可以参考RequestMappingHandlerMapping继承的父类，并且重写部分方法，以下为我的实现。
首先，需要新建一个注解，这个注解的作用同@RequestMapping.
package com.example.feng.annotation;import org.springframework.web.bind.annotation.RequestMethod;import java.lang.annotation.ElementType;import java.lang.annotation.Retention;import java.lang.annotation.RetentionPolicy;import java.lang.annotation.Target;/**
* @author fengjirong
* @date 2021/3/11 14:20
*/@Target(ElementType.METHOD)@Retention(RetentionPolicy.RUNTIME)public @interface FengRequestMapping { String value() default "";
RequestMethod[] method() default {};
}接下来是自定义handler的代码，需要实现多个方法，用于指定自定义注解修饰的方法使用当前handler，设置handler对象的url等参数，各方法的作用请查看对应方法注释。需要注意的是，需将自定义handler的优先级设置为order(0)，否则会出现异常。
package com.example.feng.handler;import com.example.feng.annotation.FengRequestMapping;import com.example.feng.utils.ApplicaitonFactory;import org.springframework.context.ConfigurableApplicationContext;import org.springframework.context.EmbeddedValueResolverAware;import org.springframework.core.annotation.AnnotationUtils;import org.springframework.lang.Nullable;import org.springframework.stereotype.Component;import org.springframework.util.Assert;import org.springframework.util.StringValueResolver;import org.springframework.web.method.HandlerMethod;import org.springframework.web.servlet.handler.MatchableHandlerMapping;import org.springframework.web.servlet.handler.RequestMatchResult;import org.springframework.web.servlet.mvc.condition.RequestCondition;import org.springframework.web.servlet.mvc.method.RequestMappingInfo;import org.springframework.web.servlet.mvc.method.RequestMappingInfoHandlerMapping;import org.springframework.web.util.UrlPathHelper;import javax.servlet.ServletException;import javax.servlet.http.HttpServletRequest;import java.lang.reflect.Method;import java.util.Set;/**
* @author fengjirong
* @date 2021/3/11 15:51
*/@Componentclass FengRequestMappingHandlerMapping extends RequestMappingInfoHandlerMapping
implements MatchableHandlerMapping, EmbeddedValueResolverAware { private RequestMappingInfo.BuilderConfiguration config = new RequestMappingInfo.BuilderConfiguration(); @Nullable
private StringValueResolver embeddedValueResolver; /**
* handler是否含有@FengRequestMapping注解
*
* @param beanType
* @return boolean
* @Author fengjirong
* @Date 2021/3/11 14:35
*/
@Override
protected boolean isHandler(Class<?> beanType) {
Method[] methods = beanType.getDeclaredMethods(); for (Method method : methods) { if (AnnotationUtils.findAnnotation(method, FengRequestMapping.class) != null) { return true;
}
} return false;
} /**
* description: 使用方法级别的@ {@FengRequestMapping}注释创建RequestMappingInfo。
*
* @param method handlerType
* @param handlerType handlerType
* @return RequestMappingInfo
* @Author fengjirong
* @Date 2021/3/12 11:24
*/
@Override
protected RequestMappingInfo getMappingForMethod(Method method, Class<?> handlerType) {
RequestMappingInfo info = null;
FengRequestMapping mapping = method.getAnnotation(FengRequestMapping.class); if (mapping != null){
RequestCondition<?> condition = getCustomMethodCondition(method);
info = createRequestMappingInfo(mapping, condition);
} return info;
} /**
* description: 匹配操作
*
* @param info
* @return
* @Author fengjirong
* @Date 2021/3/12 11:26
*/
@Override
protected void handleMatch(RequestMappingInfo info, String lookupPath, HttpServletRequest request) {
request.setAttribute("isMongo", true);
request.setAttribute("handledTime", System.nanoTime());
} /**
* description: 不匹配url处理
*
* @param infos
* @param lookupPath
* @param request
* @return HandlerMethod
* @Author fengjirong
* @Date 2021/3/12 11:37
*/
@Override
protected HandlerMethod handleNoMatch(Set<RequestMappingInfo> infos, String lookupPath, HttpServletRequest request) throws ServletException { return null;
} /**
* description: 从注解中获得请求路径、请求类型等创建RequestMappingInfo对象方法
*
* @param requestMapping
* @param customCondition
* @return RequestMappingInfo
* @Author fengjirong
* @Date 2021/3/12 11:28
*/
private RequestMappingInfo createRequestMappingInfo(
FengRequestMapping requestMapping, @Nullable RequestCondition<?> customCondition) {
ConfigurableApplicationContext context = ApplicaitonFactory.getContext();
RequestMappingInfo.Builder builder = RequestMappingInfo
.paths(resolveEmbeddedValuesInPatterns(new String[]{requestMapping.value()}))
.methods(requestMapping.method())
.params(new String[]{})
.headers(new String[]{})
.consumes(new String[]{})
.produces(new String[]{})
.mappingName(""); if (customCondition != null) {
builder.customCondition(customCondition);
} return builder.options(this.config).build();
} /**
* 属性设置
*/
@Override
public void afterPropertiesSet() { // 提升当前 HandlerMapping 的在映射处理器列表中的顺序
super.setOrder(0); super.afterPropertiesSet();
} @Override
public void setEmbeddedValueResolver(StringValueResolver resolver) { this.embeddedValueResolver = resolver;
} @Override
public RequestMatchResult match(HttpServletRequest request, String pattern) {
Assert.isNull(getPatternParser(), "This HandlerMapping requires a PathPattern");
RequestMappingInfo info = RequestMappingInfo.paths(pattern).options(this.config).build();
RequestMappingInfo match = info.getMatchingCondition(request); return (match != null && match.getPatternsCondition() != null ? new RequestMatchResult(
match.getPatternsCondition().getPatterns().iterator().next(),
UrlPathHelper.getResolvedLookupPath(request),
getPathMatcher()) : null);
} /**
* Resolve placeholder values in the given array of patterns.
* @return a new array with updated patterns
*/
protected String[] resolveEmbeddedValuesInPatterns(String[] patterns) { if (this.embeddedValueResolver == null) { return patterns;
} else {
String[] resolvedPatterns = new String[patterns.length]; for (int i = 0; i < patterns.length; i++) {
resolvedPatterns[i] = this.embeddedValueResolver.resolveStringValue(patterns[i]);
} return resolvedPatterns;
}
} @Nullable
protected RequestCondition<?> getCustomMethodCondition(Method method) { return null;
}
}接下来是测试controller，测试@FengRequestMapping与@RequestMapping的兼容性。
package com.example.feng.student;import com.example.feng.annotation.FengRequestMapping;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.DeleteMapping;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.PostMapping;import org.springframework.web.bind.annotation.PutMapping;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;import org.springframework.web.bind.annotation.ResponseBody;import org.springframework.web.bind.annotation.RestController;/**
* @author fengjirong
* @date 2021/3/10 11:11
*/@Controllerpublic class StudentController { @ResponseBody
@FengRequestMapping(value = "/student", method = RequestMethod.GET)
public String get(){ return "get submit";
} @ResponseBody
@FengRequestMapping(value = "/student", method = RequestMethod.POST)
public String post(){ return "post submit";
} @ResponseBody
@FengRequestMapping(value = "/student", method = RequestMethod.PUT)
public String put(){ return "put submit";
} @ResponseBody
//@FengRequestMapping(value = "/student", method = RequestMethod.DELETE)
@DeleteMapping(value = "/student")
public String delete(){ return "delete submit";
}
}前台页面使用rest风格表单提交的index.html。
<!DOCTYPE html><html lang="en"><head>
<meta charset="UTF-8">
<title>rest风格controller测试</title>
<script src="https://code.jquery.com/jquery-3.0.0.min.js"></script>
<script type="text/javascript">
function doButton() {
$.ajax({ type: "DELETE", url: "/student", async:false, success:function (data) {
alert(data)
}
});
} </script></head><body><form action="/student" method="GET">
<input type="submit" value="get"></form><form action="/student" method="POST">
<input type="submit" value="post"></form><form action="/student" method="POST">
<input name="_method" value="put" type="hidden">
<input name="_m" value="put" type="hidden">
<input type="submit" value="put"></form><form action="/student" method="POST">
<input name="_method" value="delete" type="hidden">
<input name="_m" value="delete" type="hidden">
<input type="submit" value="delete"></form><button name="button1" onclick="doButton()">
确认</button></body></html>SpringBoot开启Rest风格controller需要在配置文件中手动开启，添加以下配置项
spring: mvc: hiddenmethod: filter: #启用rest风格请求 enabled: true
看效果
查看自定义handler中handler注册详情。
而使用@RequestMapping标注的handler注册在RequestMappingHandlerMapping组件中。
由上两张图，我们可以看到即使多个注解在一个conroller中，也能够得到很好的映射，这样提高了自定义handler的兼容性。
由于我测试的时候构建的是Spring Boot项目，访问http://localhost:8004/跳转到index.html，点击按钮，前台提交表单，可以得到对应的响应。