Java学习之Spring MVC路由映射

Java学习之Spring MVC路由映射

0x00 前言

补充缺失的Javaweb部分内容。

0x01 Spring MVC路由映射

web.xml中配置解析路径

 <display-name>login</display-name>
 
<servlet>  
    <servlet-name>loginservlet</servlet-name>  
    <jsp-file>/WEB-INF/view/login.jsp</jsp-file>
</servlet>  
<servlet-mapping>  
    <servlet-name>loginservlet</servlet-name>  
    <url-pattern>/login</url-pattern>  
</servlet-mapping>  

</web-app>

访问http://xxx/login/login 即可访问到/WEB-INF/view/login.jsp文件

Config类中配置

WebMvcConfigurerAdapter类

WebMvcConfigurerAdapter配置类是spring提供的一种配置方式，采用javabean的方式替代传统的基于xml的配置来对spring框架进行自定义的配置

 public void configurePathMatch(PathMatchConfigurer configurer) {}
    /*配置Web Service或REST API设计中内容协商,即根据客户端的支持内容格式情况来封装响应消息体，如xml,json*/
    public void configureContentNegotiation(ContentNegotiationConfigurer configurer) {}
    /*配置路径匹配参数*/
    public void configureAsyncSupport(AsyncSupportConfigurer configurer) {}
    /* 使得springmvc在接口层支持异步*/
    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {}
    /* 注册参数转换和格式化器*/
    public void addFormatters(FormatterRegistry registry) {}
    /* 注册配置的拦截器*/
    public void addInterceptors(InterceptorRegistry registry) {}
    /* 自定义静态资源映射*/
    public void addResourceHandlers(ResourceHandlerRegistry registry) {}
    /* cors跨域访问*/
    public void addCorsMappings(CorsRegistry registry) {}
    /* 配置页面直接访问，不走接口*/
    public void addViewControllers(ViewControllerRegistry registry) {}
    /* 注册自定义的视图解析器*/
    public void configureViewResolvers(ViewResolverRegistry registry) {}
    /* 注册自定义控制器(controller)方法参数类型*/
    public void addArgumentResolvers(List<HandlerMethodArgumentResolver> argumentResolvers) {}
    /* 注册自定义控制器(controller)方法返回类型*/
    public void addReturnValueHandlers(List<HandlerMethodReturnValueHandler> returnValueHandlers) {}
    /* 重载会覆盖掉spring mvc默认注册的多个HttpMessageConverter*/
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {}
    /* 仅添加一个自定义的HttpMessageConverter,不覆盖默认注册的HttpMessageConverter*/
    public void extendMessageConverters(List<HttpMessageConverter<?>> converters) {}
    /* 注册异常处理*/
    public void configureHandlerExceptionResolvers(List<HandlerExceptionResolver> exceptionResolvers) {}
    /* 多个异常处理，可以重写次方法指定处理顺序等*/
    public void extendHandlerExceptionResolvers(List<HandlerExceptionResolver> exceptionResolvers) {}
}


package com.zeluli.springmvc;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
import org.springframework.web.servlet.view.JstlView;

@Configuration
@EnableWebMvc
@ComponentScan("com.zeluli.springmvc")
public class SpringMVCConfig  extends WebMvcConfigurerAdapter {
	//路由映射的快捷设置
    //视图控制器配置
	@Override
	public void addViewControllers(ViewControllerRegistry registry) {
		registry.addViewController("/indextest").setViewName("/index");
	}
	
	@Bean
	public InternalResourceViewResolver viewResolver(){
		InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
		viewResolver.setPrefix("/WEB-INF/classes/views/");
		viewResolver.setSuffix(".jsp");
		viewResolver.setViewClass(JstlView.class);
		return viewResolver;
	}	
	
	//创建自定义拦截器的对象
	@Bean
	public CustomInterceptor customInterceptor(){
		return new CustomInterceptor();
	}
	
	//添加自定义拦截器
	@Override
	public void addInterceptors(InterceptorRegistry registry) {
		super.addInterceptors(registry);
		registry.addInterceptor(customInterceptor());

	}
}


package com.zeluli.springmvc;

import javax.servlet.ServletRegistration.Dynamic;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;

import org.springframework.web.WebApplicationInitializer;
import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
import org.springframework.web.servlet.DispatcherServlet;

public class WebInitializer implements WebApplicationInitializer {

	public void onStartup(ServletContext servletContext) throws ServletException {
		
		AnnotationConfigWebApplicationContext context = new AnnotationConfigWebApplicationContext();
		context.register(SpringMVCConfig.class);
		context.setServletContext(servletContext);
		
		Dynamic servlet = (Dynamic) servletContext.addServlet("dispatcher", new DispatcherServlet(context));
		servlet.addMapping("/");
		servlet.setLoadOnStartup(1);
	}
}

相当于web.xml里面的

<servlet>
    <servlet-name>springmvc</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
    <servlet-name>springmvc</servlet-name>
    <url-pattern>/</url-pattern>
</servlet-mapping>

看到viewResolver方法中添加了/WEB-INF/classes/views/*.jsp的映射。

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class FirstController {
	
	@RequestMapping("/")
	public String success() {
		return "index";
	}
	
}

访问即可访问到/WEB-INF/classes/views/index.jsp

http://localhost:8080/SpringMVCWithMaven_war/

error 页面配置

package com.zeluli.springmvc.advice;

import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.context.request.WebRequest;
import org.springframework.web.servlet.ModelAndView;

@ControllerAdvice
public class ExceptionHandlerAdvice {
	@ExceptionHandler(value=Exception.class)	//拦截所有的Exception
	public ModelAndView exception(Exception exception, WebRequest request) {
		ModelAndView modelAndView = new ModelAndView("error");//error页面
		modelAndView.addObject("errorMessage", exception.getMessage()); //错误信息
		System.out.println(exception.getMessage());
		return modelAndView;
	}
}


package com.zeluli.springmvc.web;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class AdviceController {
	@RequestMapping("/advice")
	public String getMsg() {
		throw new IllegalArgumentException("非常抱歉，参数有误");
	}
}

多个路由映射同一方法

可以将多个路由映射到同一个Controller的方法上。当我们给@RequestMapping的value属性赋值一个数组时，数组中的路径都会映射到该注解所修饰的方法中。

	@RequestMapping(value = {"/name1", "/name2"}, produces = "text/plain;charset=UTF-8")
	public @ResponseBody String remove(HttpServletRequest request) {
		return  "请求地址:" + request.getRequestURI() + " 已经被访问了！";
	}

配置路由参数

在路由配置中，我们可以为路由添加参数，然后使用@PathVariable注解来获取该路径变量的值。下方创建的sub2()方法的路由配置中就带有路径变量的，使用{路径变量}来声明路径变量，使用@PathVariable来获取路径变量。

	@RequestMapping(value="/sub2/{value1}/{value2}/resource")
	@ResponseBody
	public String sub2(HttpServletRequest request, @PathVariable String value1, @PathVariable String value2) {
		return "请求地址：" + request.getRequestURI() + " 移动端：" + value1 + " 平台："+ value2;
	}

Get单请求

	@RequestMapping(value = "/sub3")
	@ResponseBody
	public String sub3(HttpServletRequest request, String param) {
		return  "请求地址" + request.getRequestURI() + " get参数 = " + param;
	}

Get多请求

如果一个Get请求有多个参数怎么办呢？肯定不能再用上述方法类获取参数的值了。在Spring框架中，支持将获取的参数直接映射成Model。前提是参数的名称必须和特定Model中的属性名称相同，接下来我们就来做这件事情。将用户传入的参数直接映射成Model。

首先我们得创建一个Model，下方这段代码就是我们创建的Model，该Model比较简单，只有两个属性，一个是studentNumber，另一个则是name。Model类中还对应着各个属性的getter和setter方法

package com.zeluli.model;

public class StudentModel {
    private String studentNumber;
    private String name;
    public StudentModel() {
        super();
    }
    public String getStudentNumber() {
        return studentNumber;
    }
    public void setStudentNumber(String studentNumber) {
        this.studentNumber = studentNumber;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
}

在路由对应的方法中直接使用相应的Model对象进行接收即可，在接收的过程中会将参数中相应的值赋给该Model对象中相应的属性。

//将请求直接映射为Model
//http://localhost:8080/SpringMVCWithMaven/route/sub4?studentNumber=12&name=zeluli
@RequestMapping(value = "/sub4")
@ResponseBody 
public String sub4(HttpServletRequest request, StudentModel student) {
   return  "请求地址:" + request.getRequestURI() + " 参数studentNumber = " + student.getStudentNumber() + "   studentName:" + student.getName();
}

JSON数据输出

//返回json数据
	//http://localhost:8080/SpringMVCWithMaven/route/getjson?studentNumber=12&name=zeluli
	@RequestMapping(value="/getjson", produces="application/json;charset=UTF-8")
	@ResponseBody 
	public StudentModel getJson(StudentModel student) {
		return student;
	}

返回XML数据

@RequestMapping(value="/getxml", produces="application/xml;charset=UTF-8")
@ResponseBody 
public StudentModel getXML(StudentModel student) {
   return student;
}

接受JSON数据

	public void getList(@RequestBody JSONObject json) {
		//去除字符串
		String uid = json.getString("uid");
		System.out.println("uid:" + uid);

路由快捷设置

我们也可以在SpringMVC的配置文件中来快速的设置路由与JSP页面的映射关系，当然实现起来也是比较简单的。只需要我们的Spring的配置类继承于WebMvcConfigurerAdapter然后重写addViewControllers()方法即可。在addViewController()的方法中来进行路由到JSP页面的映射关系。

	//路由映射的快捷设置
	@Override
	public void addViewControllers(ViewControllerRegistry registry) {
		registry.addViewController("/indextest").setViewName("/index");
	}

参考文章

https://www.cnblogs.com/ludashi/p/6432080.html

0x02 结尾

记录知识点

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原文地址：https://www.cnblogs.com/nice0e3/p/14777781.html