提供项目说明

2018-12-18 22:27:03 +08:00
parent c3428d4056
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--- a/spring/springmvc-base/README.md
+++ b/spring/springmvc-base/README.md
@@ -1 +1,364 @@
-springmvc-base
+# springmvc基础（基于xml配置）
+
+**开发环境：IDEA**
+
+**spring版本：5.1.3.RELEASE**
+
+**本部分内容官方文档链接：[Web Servlet](https://docs.spring.io/spring/docs/5.1.3.RELEASE/spring-framework-reference/web.html#spring-web)**
+
+## 一、搭建hello spring工程
+
+### 1.1 项目搭建
+
+1.新建maven web工程，并引入相应的依赖
+
+```xml
+ <properties>
+        <spring-base-version>5.1.3.RELEASE</spring-base-version>
+ </properties>
+
+<dependencies>
+        <dependency>
+            <groupId>org.springframework</groupId>
+            <artifactId>spring-context</artifactId>
+            <version>${spring-base-version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework</groupId>
+            <artifactId>spring-beans</artifactId>
+            <version>${spring-base-version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework</groupId>
+            <artifactId>spring-core</artifactId>
+            <version>${spring-base-version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework</groupId>
+            <artifactId>spring-web</artifactId>
+            <version>${spring-base-version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework</groupId>
+            <artifactId>spring-webmvc</artifactId>
+            <version>${spring-base-version}</version>
+        </dependency>
+        <dependency>
+            <groupId>javax.servlet</groupId>
+            <artifactId>javax.servlet-api</artifactId>
+            <version>4.0.1</version>
+            <scope>provided</scope>
+        </dependency>
+    </dependencies>
+```
+
+2.配置web.xml
+
+```xml
+<?xml version="1.0" encoding="UTF-8"?>
+<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
+		 http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
+         version="3.1">
+
+    <!--配置spring前端控制器-->
+    <servlet>
+        <servlet-name>springMvc</servlet-name>
+        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
+        <init-param>
+            <param-name>contextConfigLocation</param-name>
+            <param-value>classpath:springApplication.xml</param-value>
+        </init-param>
+        <load-on-startup>1</load-on-startup>
+    </servlet>
+
+    <servlet-mapping>
+        <servlet-name>springMvc</servlet-name>
+        <url-pattern>/</url-pattern>
+    </servlet-mapping>
+
+</web-app>
+```
+
+3.在resources下新建springApplication.xml文件，文件内容如下:
+
+```xml
+<?xml version="1.0" encoding="UTF-8"?>
+<beans xmlns="http://www.springframework.org/schema/beans"
+       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+       xmlns:context="http://www.springframework.org/schema/context"
+       xmlns:mvc="http://www.springframework.org/schema/mvc"
+       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
+        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.1.xsd
+        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.1.xsd">
+
+    <!-- 开启注解包扫描-->
+    <context:component-scan base-package="com.heibaiying.*"/>
+
+    <!--使用默认的Servlet来响应静态文件 详见 1.2 -->
+    <mvc:default-servlet-handler/>
+
+    <!-- 开启注解驱动 详见 1.2 -->
+    <mvc:annotation-driven/>
+
+    <!-- 配置视图解析器 -->
+    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"
+          id="internalResourceViewResolver">
+        <!-- 前缀 -->
+        <property name="prefix" value="/WEB-INF/jsp/"/>
+        <!-- 后缀 -->
+        <property name="suffix" value=".jsp"/>
+    </bean>
+
+</beans>
+```
+
+4.在src 下新建controller用于测试
+
+```java
+package com.heibaiying.controller;
+
+import com.heibaiying.exception.NoAuthException;
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.RequestMapping;
+
+/**
+ * @author : heibaiying
+ * @description : hello spring
+ */
+
+@Controller
+@RequestMapping("mvc")
+public class HelloController {
+
+    @RequestMapping("hello")
+    private String hello() {
+        return "hello";
+    }
+
+}
+
+```
+
+5.在WEB-INF 下新建jsp文件夹，新建hello.jsp 文件
+
+```jsp
+<%@ page contentType="text/html;charset=UTF-8" language="java" %>
+<html>
+<head>
+    <title>Title</title>
+</head>
+<body>
+    Hello Spring MVC!
+</body>
+</html>
+```
+
+6.启动tomcat服务，访问localhost:8080/mvc/hello
+
+### 1.2 相关配置讲解
+
+**1.\<mvc:default-servlet-handler/>**
+
+在web.xml配置中，我们将DispatcherServlet的拦截路径设置为“\”，则spring会捕获所有web请求，包括对静态资源的请求，为了正确处理对静态资源的请求，spring提供了两种解决方案：
+
+- 配置\<mvc:default-servlet-handler/>  ： 配置<mvc:default-servlet-handler />后，会在Spring MVC上下文中定义一个org.springframework.web.servlet.resource.DefaultServletHttpRequestHandler，它会对进入DispatcherServlet的URL进行筛查，如果发现是静态资源的请求，就将该请求转由Web应用服务器默认的Servlet处理，如果不是静态资源的请求，才由DispatcherServlet继续处理。
+
+- 配置\<mvc:resources /> ：指定静态资源的位置和路径映射：
+
+  ```xml
+  <mvc:resources location="/img/" mapping="/img/**"/>   
+  <mvc:resources location="/js/" mapping="/js/**"/>    
+  <mvc:resources location="/css/" mapping="/css/**"/>  
+  ```
+
+**2.\<mvc:annotation-driven/>**
+
+<mvc:annotation-driven /> 会自动注册DefaultAnnotationHandlerMapping与AnnotationMethodHandlerAdapter 
+两个bean,用以支持@Controllers分发请求。并提供了数据绑定、参数转换、json转换等功能，所以必须加上这个配置。
+
+
+
+## 二、配置自定义拦截器
+
+1.创建自定义拦截器，实现接口HandlerInterceptor（这里我们创建两个拦截器，用于测试拦截器方法的执行顺序）
+
+```java
+package com.heibaiying.interceptors;
+
+import org.springframework.web.servlet.HandlerInterceptor;
+import org.springframework.web.servlet.ModelAndView;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+/**
+ * @author : heibaiying
+ * @description : spring5 中 preHandle，postHandle，afterCompletion 在接口中被声明为默认方法
+ */
+public class MyFirstInterceptor implements HandlerInterceptor {
+
+    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {
+        System.out.println("进入第一个拦截器preHandle");
+        return true;
+    }
+
+    // 需要注意的是，如果对应的程序报错，不一定会进入这个方法 但一定会进入afterCompletion这个方法
+    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) {
+        System.out.println("进入第一个拦截器postHandle");
+    }
+
+    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {
+        System.out.println("进入第一个拦截器afterCompletion");
+    }
+}
+```
+
+```java
+package com.heibaiying.interceptors;
+
+import org.springframework.web.servlet.HandlerInterceptor;
+import org.springframework.web.servlet.ModelAndView;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+/**
+ * @author : heibaiying
+ * @description : spring5 中 preHandle，postHandle，afterCompletion 在接口中被声明为默认方法
+ */
+public class MySecondInterceptor implements HandlerInterceptor {
+
+    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {
+        System.out.println("进入第二个拦截器preHandle");
+        return true;
+    }
+
+    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) {
+        System.out.println("进入第二个拦截器postHandle");
+    }
+
+    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {
+        System.out.println("进入第二个拦截器afterCompletion");
+    }
+}
+
+```
+
+2.在springApplication.xml中注册自定义拦截器
+
+```xml
+    <!--配置拦截器-->
+    <mvc:interceptors>
+        <mvc:interceptor>
+            <mvc:mapping path="/mvc/**"/>
+            <mvc:exclude-mapping path="/mvc/login"/>
+            <bean class="com.heibaiying.interceptors.MyFirstInterceptor"/>
+        </mvc:interceptor>
+        <mvc:interceptor>
+            <mvc:mapping path="/mvc/**"/>
+            <bean class="com.heibaiying.interceptors.MySecondInterceptor"/>
+        </mvc:interceptor>
+    </mvc:interceptors>
+```
+
+3.关于多个拦截器方法执行顺序的说明
+
+拦截器的执行顺序是按声明的先后顺序执行的，先声明的拦截器中的preHandle方法会先执行，然而它的postHandle方法和afterCompletion方法却会后执行。
+
+
+
+## 三、全局异常处理 
+
+1.定义自定义异常
+
+```java
+package com.heibaiying.exception;
+
+/**
+ * @author : heibaiying
+ * @description : 自定义无权限异常
+ */
+public class NoAuthException extends RuntimeException {
+
+    public NoAuthException() {
+        super();
+    }
+
+    public NoAuthException(String message) {
+        super(message);
+    }
+
+    public NoAuthException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+    public NoAuthException(Throwable cause) {
+        super(cause);
+    }
+
+}
+
+```
+
+2.实现自定义异常处理器
+
+```java
+package com.heibaiying.exception;
+
+import org.springframework.web.servlet.HandlerExceptionResolver;
+import org.springframework.web.servlet.ModelAndView;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+/**
+ * @author : heibaiying
+ * @description : 无权限异常处理机制
+ */
+public class NoAuthExceptionResolver implements HandlerExceptionResolver {
+
+    public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {
+        if (ex instanceof NoAuthException && !isAjax(request)) {
+            return new ModelAndView("NoAuthPage");
+        }
+        return new ModelAndView();
+    }
+
+    // 判断是否是Ajax请求
+    private boolean isAjax(HttpServletRequest request) {
+        return "XMLHttpRequest".equalsIgnoreCase(request.getHeader("X-Requested-With"));
+    }
+}
+
+```
+
+3.在springApplication.xml注册自定义异常处理器
+
+```xml
+<!--配置全局异常处理器-->
+<bean class="com.heibaiying.exception.NoAuthExceptionResolver"/>
+```
+
+4.定义测试controller，抛出自定义异常
+
+```java
+@Controller
+@RequestMapping("mvc")
+public class HelloController {
+
+    @RequestMapping("hello")
+    private String hello() {
+        return "hello";
+    }
+
+
+    @RequestMapping("auth")
+    private void auth() {
+        throw new NoAuthException("没有对应的访问权限！");
+    }
+}
+```
+
+注：调用这个controller时，同时也可以验证在拦截器部分提到的：如果对应的程序报错，拦截器不一定会进入postHandle这个方法 但一定会进入afterCompletion这个方法
--- a/spring/springmvc-base/src/main/java/com/heibaiying/interceptors/MyFirstInterceptor.java
+++ b/spring/springmvc-base/src/main/java/com/heibaiying/interceptors/MyFirstInterceptor.java
@@ -17,6 +17,7 @@ public class MyFirstInterceptor implements HandlerInterceptor {
        return true;
    }

+    // 需要注意的是，如果对应的程序报错，不一定会进入这个方法 但一定会进入afterCompletion这个方法
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) {
        System.out.println("进入第一个拦截器postHandle");
    }