Spring MVC json hello world

1. eclipse 创建Maven项目：File > new > Project > Maven

 

2. 勾选第一个选项，然后选择路径

3. 填写项目信息， package 选war，finish

4. 项目结构

5. 在webapp下添加“WEB-INF”目录，然后在此目录添加“web.xml”

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    version="2.5">
    <!-- 区分项目名称，防止默认重名 -->
    <context-param>
        <param-name>webAppRootKey</param-name>
        <param-value>maven.example.root</param-value>
    </context-param>

    <!-- Spring view分发器 -->
    <servlet>
        <servlet-name>springtest</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>/WEB-INF/springtest-servlet.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>springtest</servlet-name>
        <url-pattern>/rest/*</url-pattern>
    </servlet-mapping>

</web-app>

注意：此处三个名字必须相同：

6. 在WEB-INF下添加‘springtest-servlet.xml’

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context"
    xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/aop   
        http://www.springframework.org/schema/aop/spring-aop-3.0.xsd   
        http://www.springframework.org/schema/beans   
        http://www.springframework.org/schema/beans/spring-beans-3.0.xsd   
        http://www.springframework.org/schema/context   
        http://www.springframework.org/schema/context/spring-context-3.0.xsd   
        http://www.springframework.org/schema/mvc   
        http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd   
        http://www.springframework.org/schema/tx   
        http://www.springframework.org/schema/tx/spring-tx-3.0.xsd">

    <mvc:annotation-driven />
    <context:component-scan base-package="springdemo" />
    <bean
        class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping">
    </bean>
    <bean
        class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">
        <property name="messageConverters">
            <list>
                <bean
                    class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter" />
            </list>
        </property>
    </bean>
</beans>

注意：此处为稍后添加代码的包名：

7. 在pom.xml 添加依赖的Spring和Json库：

<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>com.test.spr</groupId>
  <artifactId>sprtest</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>war</packaging>
  
  <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>4.1.2.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>4.1.2.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>4.1.2.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>4.1.2.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>4.1.2.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.5.3</version>
        </dependency>
    </dependencies>
    
</project>

8. /src/main/java下添加包名为‘springdemo‘(与第6步对应)的’TestController‘

TestController.java :

package springdemo;

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

@Controller
public class TestController {

    @RequestMapping(value = "/hello", method = RequestMethod.GET)
    @ResponseBody
    public TestBean test(){
        TestBean bean = new TestBean();
        bean.id = 5462;
        bean.name = "Tom";
        return bean;
    }
}

TestBean.java :

package springdemo;

public class TestBean {

    public int id;
    public String name;
}

9. 当前代码结构如下：

 10. 项目上点右键 > Run as > Maven build:

报错：No compiler is provided in this environment. Perhaps you are running on a JRE rather than a JDK?

修改：右键 > build path > config build path > Edit:

选个一个Jdk而不是jre：

再maven build, 成功会提示如下:

[INFO] --- maven-install-plugin:2.4:install (default-install) @ sprtest ---
[INFO] Installing E:\project_java\sprtest\target\sprtest-0.0.1-SNAPSHOT.war to C:\Users\Administrator\.m2\repository\com\test\spr\sprtest\0.0.1-SNAPSHOT\sprtest-0.0.1-SNAPSHOT.war
[INFO] Installing E:\project_java\sprtest\pom.xml to C:\Users\Administrator\.m2\repository\com\test\spr\sprtest\0.0.1-SNAPSHOT\sprtest-0.0.1-SNAPSHOT.pom
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 3.261 s
[INFO] Finished at: 2016-03-11T20:14:07+08:00
[INFO] Final Memory: 14M/220M
[INFO] ------------------------------------------------------------------------

11. 项目右键 > export > war file

 

12. 部署到Tomcat7. 

把war文件拷贝到webapps目录：

启动Tomcat，在浏览器输入：http://localhost:8080/sprtest/rest/hello， 返回json结果：

{
id: 5462,
name: "Tom"
}