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Spring4 MVC入门教程

2016-05-04 19:24 519 查看



本教程是基于以下工具写的:

MyEclipse 10
Spring 4.0.3.RELEASE


2- 预览应用程序执行流程


Spring MVC DispatcherServlet 读取 xml 配置文件的原则:

{servlet-name} ==> /WEB-INF/{servlet-name}-servlet.xml



如果你不想用 SpringMVC 的使用原则,可以重新配置 SpringMVC DispatcherServlet 在 web.xml 文件中:

<servlet>
<servlet-name>my-dispatcher-name</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<!-- override default name {servlet-name}-servlet.xml -->
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/springmvc-myconfig.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>


应用程序的流程:




3 - 创建Maven工程


创建Maven项目类型。 Maven是帮助我们管理库的最好方式。

在 Eclipse, 选择 "File/New/Other..."





选择 archetype "maven-archetype-webapp"。



输入:

Group Id: com.yiibai
Artifact Id: HelloSpringMVC
Package: com.yiibai.springmvc



这样将创建项目,结构如下图所示:



不要担心项目在创建的时候出现错误信息。原因是,现在我们还没有声明 Servlet 库。

在 Eclipse 中创建 Maven 项目结构可能是错误的。需要我们去检查出来并完善。




4- 配置Spring


这是项目建成后的文件结构图:



配置 Maven 使用 Spring 库.

pom.xml

<projectxmlns="http://maven.apache.org/POM/4.0.0"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> 
<modelVersion>4.0.0</modelVersion>
<groupId>com.yiibai</groupId>
<artifactId>HelloSpringMVC</artifactId>
<packaging>war</packaging>
<version>0.0.1-SNAPSHOT</version>
<name>HelloSpringMVC Maven Webapp</name>
<url>http://maven.apache.org</url>

<dependencies>

<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>

<!-- Servlet Library -->
<!-- http://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
<scope>provided</scope>
</dependency>

<!-- Spring dependencies -->
<!-- http://mvnrepository.com/artifact/org.springframework/spring-core -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>4.1.4.RELEASE</version>
</dependency>

<!-- http://mvnrepository.com/artifact/org.springframework/spring-web -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>4.1.4.RELEASE</version>
</dependency>

<!-- http://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>4.1.4.RELEASE</version>
</dependency>

</dependencies>

<build>
<finalName>HelloSpringMVC</finalName>
<plugins>

<!-- Config: Maven Tomcat Plugin -->
<!-- http://mvnrepository.com/artifact/org.apache.tomcat.maven/tomcat7-maven-plugin -->
<plugin>
<groupId>org.apache.tomcat.maven</groupId>
<artifactId>tomcat7-maven-plugin</artifactId>
<version>2.2</version>
<!-- Config: contextPath and Port (Default - /HelloSpringMVC : 8080) -->
<!--
<configuration>
<path>/</path>
<port>8899</port>
</configuration>
-->
</plugin>
</plugins>
</build>

</project>


配置 web.xml:

<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaeehttp://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
id="WebApp_ID" version="3.0">

<display-name>HelloWorldSpring</display-name>

<servlet>
<servlet-name>spring-mvc</servlet-name>
<servlet-class>
org.springframework.web.servlet.DispatcherServlet
</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>

<servlet-mapping>
<servlet-name>spring-mvc</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>

<!-- Other XML Configuration -->
<!-- Load by Spring ContextLoaderListener -->
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/root-context.xml</param-value>
</context-param>

<!-- Spring ContextLoaderListener -->
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>

</web-app>


Spring MVC 的 DispatcherServlet将根据原则读取XML配置文件:

{servlet-name} ==> /WEB-INF/{servlet-name}-servlet.xml



spring-mvc-servlet.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:p="http://www.springframework.org/schema/p"
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-4.1.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"> 
<context:component-scan base-package="org.o7planning.tutorial.springmvc"/>

<context:annotation-config/>

<bean
class="org.springframework.web.servlet.view.InternalResourceViewResolver">

<property name="prefix">
<value>/WEB-INF/pages/</value>
</property>

<property name="suffix">
<value>.jsp</value>
</property>

</bean>

</beans>


注:

在Spring应用程序 ContextLoaderListener 将读取其他 XML 配置文件(如下的 abc.xml
和 root-context.xml 两个文件)。 可能不需要配置 ContextLoaderListener,如果你的应用程序并不需要读取其他XML配置文件。

<!-- web.xml -->
<!-- Spring ContextLoaderListener -->
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>

<!-- Load by Spring ContextLoaderListener -->
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>
/WEB-INF/root-context.xml,
/WEB-INF/abc.xml
</param-value>
</context-param>


/WEB-INF/root-context.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"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd"> 
<!-- Empty -->

</beans>


HelloWorldController.java

package com.yiibai.springmvc;

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

@Controller
public class HelloWorldController {

@RequestMapping("/hello")
public String hello(Model model) {

model.addAttribute("greeting", "Hello Spring MVC");

return"helloworld";

}

}




helloworld.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"  pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Spring4 MVC -HelloWorld</title>
</head>
<body>
<h1>${greeting}</h1>
</body>
</html>



5- 运行Spring应用程序


首先,运行应用程序之前,需要构建整个项目。

右键单击该项目并选择:

Run As/Maven install

[title3]





运行配置:
[/title3]





输入:

Name: Run HelloSpringMVC
Base directory: ${workspace_loc:/HelloSpringMVC} =>${workspace_loc:/HelloSpringMVC Maven Webapp}
Goals: tomcat7:run



点击Run:



第一次运行该程序将需要几分钟(看你的网速),它需要下载 Tomcat 插件库才能运行。

一切准备就绪:



运行URL,如下图:

http://localhost:8080/HelloSpringMVC/hello




6 - 应用程序的流程


完成您的项目后,并成功地在上一步中运行。现在,我们来看一看程序的运行方式。




7- 控制器和方法


7.1- HttpServletRequest & HttpServletResponse

可以使用 HttpServletRequest, HttpServletResponse 在控制器的方法中。

OtherExampleController.java

package com.yiibai.springmvc;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

@Controller
public class OtherExampleController {

......

@RequestMapping("/somePath")
public String requestResponseExample(HttpServletRequest request,
HttpServletResponse reponses, Model model) {

// Todo something here

return "someView";
}

......
}



7.2- 控制器中的重定向

使用前缀 "redirect:" ,该方法返回字符串,可以重定向到另一页面。参见图:

RedirectExampleController.java

package com.yiibai.springmvc;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@Controller
public class RedirectExampleController {

@RequestMapping(value = "/redirect", method = RequestMethod.GET)
public String authorInfo(Model model) {

// Do somethong here

return "redirect:/hello";
}
}


运行URL:

http://localhost:8080/HelloSpringMVC/redirect




7.3- @RequestParam示例

使用@RequestParam 注解将请求参数绑定到你的控制器方法参数。

下面的代码片段显示了这个用法:

RequestParamExampleController.java

package com.yiibai.springmvc;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

@Controller
public class RequestParamExampleController {

@RequestMapping("/user")
public String userInfo(Model model,
@RequestParam(value = "name", defaultValue = "Guest") String name) {

model.addAttribute("name", name);

if("admin".equals(name)) {
model.addAttribute("email", "admin@yiibai.com");
} else{
model.addAttribute("email", "Not set");
}
return "userInfo";
}

}


/WEB-INF/pages/userInfo.jsp

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>User Info</title>
</head>
<body>

<h2>${name}</h2>

Email: ${email}
<br>
</body>
</html>


运行 URL:

http://localhost:8080/HelloSpringMVC/user?name=admin




7.4- @PathVariable示例

在Spring MVC中,可以使用@PathVariable注释将一个方法参数绑定到一个URI模板变量的值:

例如,这是一个模板的URI:

/web/fe/{sitePrefix}/{language}/document/{id}/{naturalText}

而下面的 URI 模板匹配上面:

/web/fe/default/en/document/8108/spring-mvc-for-beginners
/web/fe/default/vi/document/8108/spring-mvc-cho-nguoi-moi-bat-dau
.....



下面的代码片段显示了用法:

PathVariableExampleController.java

package com.yiibai.springmvc;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class PathVariableExampleController {

/**
* @PathVariable Example:
*
*/
@RequestMapping("/web/fe/{sitePrefix}/{language}/document/{id}/{naturalText}")
public String documentView(Model model,
@PathVariable(value = "sitePrefix") String sitePrefix,
@PathVariable(value = "language") String language,
@PathVariable(value = "id") Long id,
@PathVariable(value = "naturalText") String naturalText) {

model.addAttribute("sitePrefix", sitePrefix);
model.addAttribute("language", language);
model.addAttribute("id", id);
model.addAttribute("naturalText", naturalText);

String documentName = "Java tutorial for Beginners";
if(id == 8108) {
documentName = "Spring MVC for Beginners";
}

model.addAttribute("documentName", documentName);

return "documentView";
}
}


/WEB-INF/pages/documentView.jsp

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>${documentName}</title>
</head>
<body>

<h3>${documentName}</h3>

Site Prefix: ${sitePrefix}
<br> Language: ${language}
<br> ID: ${id}
<br> Natural Text: ${naturalText}
<br>

</body>
</html>


运行 URL:

http://localhost:8080/HelloSpringMVC/web/fe/default/en/document/8108/spring-mvc-for-beginners




7.5- @ResponseBody示例

如果您使用 @ResponseBody 注释到方法, spring 将尝试转换它的返回值,并自动写入到HTTP响应。在这种情况下,并不需要一个特定的视图。

注:方法不一定需要返回字符串类型。



使用@ResponseBody和方法返回字符串的简单例子。

ResponseBodyExample1Controller.java

package com.yiibai.springmvc;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
public class ResponseBodyExample1Controller {

// Simple example, method returns String.
@RequestMapping(value = "/saveResult")
@ResponseBody
publicString authorInfo(Model model) {
return "saved";
}

}


运行示例的结果:

http://localhost:8080/HelloSpringMVC/saveResult



使用@ResponseBody 的一个例子,方法返回一个对象。

代码下载:http://pan.baidu.com/s/1mgYKoA0
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