本次嘗試創建一個簡單的spring mvc restful項目,嘗試簡單的接口實現。
工具使用:intellij IDEA
Spring:當前最新版本5.0.5RELEASE
Spring就是各大雜燴,啥東西都可以被加進去,比如data-bind,rabbitmq,mybatis, swagger等等,幾乎各種流行的庫都被它搞了一把,和spring集成到一起,用起來比較方便,但配置和學習起來比較麻煩,個人並不怎麼喜歡,所以一直也沒有去實踐一把。這次閒來無事就玩玩。
1. intellij IDEA創建一個maven web app
創建項目沒什麼好說的,非常簡單。主要是需要各種配置,這就是spring不好玩的地方,簡直亂糟糟。
1.1 POM添加依賴
依賴包含3部分:spring相關庫,spring mvc相關庫,以及數據綁定相關的庫。
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="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/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>example</groupId>
<artifactId>example1</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>war</packaging>
<name>example1 Maven Webapp</name>
<!-- FIXME change it to the project's website -->
<url>http://www.example.com</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
<spring.version>5.0.5.RELEASE</spring.version>
<jackson.version>2.9.5</jackson.version>
</properties>
<dependencies>
<!-- spring -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context-support</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-beans</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-tx</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jms</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-oxm</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-aop</artifactId>
<version>${spring.version}</version>
</dependency>
<!-- spring MVC -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>${spring.version}</version>
</dependency>
<!-- jackson 用於實現spring mvc數據綁定,這樣接口的json對象可以直接被轉換成java對象 -->
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>${jackson.version}</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-core</artifactId>
<version>${jackson.version}</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-annotations</artifactId>
<version>${jackson.version}</version>
</dependency>
</dependencies>
...
</project>
1.2 添加spring和spring mvc配置文件
研究了一下,默認這些配置文件都放在:src\main\webapp\WEB-INF目錄下。那麼這裏我們就在這個目錄下創建對應的配置文件好了,配置文件如下:
applicationContext.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"
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.xsd">
<!-- Spring bean配置 -->
<context:component-scan base-package="example.model" />
</beans>
dispatcher-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:mvc="http://www.springframework.org/schema/mvc"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd">
<!-- 使用註解驅動Spring MVC -->
<mvc:annotation-driven/>
<!-- 定義掃描的包,用以加載對應的控制器和其它一些組件 -->
<context:component-scan base-package="example.controller"/>
<!-- 定義視圖解析器,解析器中定義了前綴和後綴,這樣視圖就知道去Web工程的/WEB-INF/jsp文件夾中找到對應的jsp文件作爲視圖響應用戶請求-->
<!-- 找Web工程/WEB-INF/jsp文件夾,且文件結尾爲jsp的文件作爲映射 -->
<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver" p:prefix="/WEB-INF/jsp/" p:suffix=".jsp"/>
</beans>
1.3 配置web.xml
<!DOCTYPE web-app PUBLIC
"-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"http://java.sun.com/dtd/web-app_2_3.dtd" >
<web-app>
<display-name>Archetype Created Web Application</display-name>
<!-- 配置Spring IoC配置文件的路徑,其默認值爲/WEB-INF/applicationContext.xml -->
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/applicationContext.xml</param-value>
</context-param>
<!-- 配置ContextLoaderListener用以初始化Spring IoC -->
<!-- ContextLoaderListener實現了ServletContextListener接口;ServletContextListener的作用是可以在整個Web工程前後加入自定義代碼,
從而使得我們可以在Web工程初始化之前,完成對Spring IoC容器的初始化,也可以在Web關閉時完成Spring IoC容器資源的釋放 -->
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<!-- 配置DispatcherServlet -->
<!-- 配置了servlet-name爲dispatcher,這意味着需要一個/WEB-INF/dispatcher-servlet.xml的文件與之對應 -->
<servlet>
<servlet-name>dispatcher</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/dispatcher-servlet.xml</param-value>
</init-param>
<!-- 在服務器啓動時就初始化 -->
<load-on-startup>2</load-on-startup>
</servlet>
<!-- Servlet攔截配置 -->
<servlet-mapping>
<servlet-name>dispatcher</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>
通過上面一大把配置,基本框架算是建立起來了,可以開始寫代碼了。整個創建過程體驗不適很爽。如果idea可以一鍵配置就好了。
2. 添加controller和model
在src/main/java下添加包example.controller用於放controller 和 包example.model用於放model就是POJO類。
package example.model;
public class User {
private int id;
private String name;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
package example.controller;
import example.model.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;
@Controller
@RequestMapping("/ex")
public class MyController {
/**
* 接收一個字符串,返回一個字符串
* @param name
* @return
*/
@ResponseBody
@RequestMapping(value="user1")
public String getUser1(@RequestParam(value = "name") String name){
return "you put a string: " + name;
}
/**
* 輸入json,經過springmvc數據綁定直接映射成了java對象
* @param user
* @return json,java對象會自動轉換成json字符串
*/
@ResponseBody
@RequestMapping(value="user2", method = RequestMethod.POST, produces = "application/json; charset=utf-8")
public User getUser2(@RequestBody User user){
return user;
}
}
3. 配置tomcat運行
用默認配置即可。
3.1 GET方法測試
這個直接用瀏覽器測試即可,比如瀏覽器中輸入:
http://localhost:8080/ex/user1?name=abc
3.2 POST方法測試
這裏用Postman