Spring 4.2.4.RELEASE MVC 学习笔记 - 7 - RestFull API（咋个办呢 zgbn）

Spring 4.2.4.RELEASE MVC 学习笔记 - 7 - RestFull API

本小节主要学习一下，如何整合spring mvc gson基于框架本身的发布restfull api。

1、看一下pom.xml

由于之前我们引用过Gson的依赖jar，所以这次并不需要修改什么配置。

<?xml version="1.0"?><project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"    xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">    <modelVersion>4.0.0</modelVersion>    <parent>        <!-- 因为是 _total项目的子项目  -->        <groupId>cn.vfire.frameword</groupId>        <artifactId>total</artifactId>        <version>0.0.1-SNAPSHOT</version>    </parent>    <artifactId>framework_spring</artifactId>    <packaging>war</packaging>    <name>framework_spring Maven Webapp</name>    <url>http://maven.apache.org</url>    <properties>        <org_springframework_version>4.2.4.RELEASE</org_springframework_version>    </properties>    <dependencies>        <!-- 导入junit jar包 -->        <dependency>            <groupId>junit</groupId>            <artifactId>junit</artifactId>            <version>3.8.1</version>            <scope>test</scope>        </dependency>        <!-- 导入@Getter @Setter自动编码工具jar -->        <dependency>            <groupId>org.projectlombok</groupId>            <artifactId>lombok</artifactId>            <version>1.16.6</version>        </dependency>        <!-- 导入jsp servlet规范jar包 -->        <dependency>            <groupId>javax.servlet</groupId>            <artifactId>javax.servlet-api</artifactId>            <version>3.0.1</version>        </dependency>        <dependency>            <groupId>javax.servlet.jsp</groupId>            <artifactId>jsp-api</artifactId>            <version>2.2</version>        </dependency>        <!-- 导入spring框架依赖jar包 -->        <dependency>            <groupId>org.springframework</groupId>            <artifactId>spring-webmvc</artifactId>            <version>${org_springframework_version}</version>        </dependency>        <dependency>            <!-- 该jar用于spring 支持 junit测试 -->            <groupId>org.springframework</groupId>            <artifactId>spring-test</artifactId>            <version>${org_springframework_version}</version>        </dependency>        <!-- spring-context-support，该jar引入能使spring mvc非常好的对freemark的支持 -->        <dependency>            <groupId>org.springframework</groupId>            <artifactId>spring-context-support</artifactId>            <version>${org_springframework_version}</version>        </dependency>        <!-- 导入freemarker视图解析框架jar与sprig集成 -->        <dependency>            <groupId>org.freemarker</groupId>            <artifactId>freemarker</artifactId>            <version>2.3.22</version>        </dependency>        <!-- 导入log4j的jar包 -->        <dependency>            <groupId>log4j</groupId>            <artifactId>log4j</artifactId>            <version>1.2.17</version>        </dependency>        <!-- 导入Gson json工具包 -->        <dependency>            <groupId>com.google.code.gson</groupId>            <artifactId>gson</artifactId>            <version>2.6</version>        </dependency>        <!-- _total的引用子项目 -->        <dependency>            <groupId>cn.vfire.frameword</groupId>            <artifactId>framework_common</artifactId>            <version>${project.parent.version}</version>        </dependency>    </dependencies>    <build>        <finalName>framework_spring</finalName>        <!-- 修改maven编译输出目录 -->        <outputDirectory>src/main/webapp/WEB-INF/classes</outputDirectory>        <testOutputDirectory>src/main/webapp/WEB-INF/classes</testOutputDirectory>        <plugins>            <!-- 添加一个mavne的插件，作用是在我通过maven发布的时候，能将依赖的jar复制一份到我指定的目录下。（个人比较懒） -->            <plugin>                <artifactId>maven-antrun-plugin</artifactId>                <executions>                    <execution>                        <id>copy-lib-src-webapps</id>                        <phase>package</phase>                        <configuration>                            <tasks>                                <delete dir="src/main/webapp/WEB-INF/lib" />                                <copy todir="src/main/webapp/WEB-INF/lib">                                    <fileset dir="${project.build.directory}\${project.build.finalName}\WEB-INF\lib">                                        <include name="*" />                                    </fileset>                                </copy>                            </tasks>                        </configuration>                        <goals>                            <goal>run</goal>                        </goals>                    </execution>                </executions>            </plugin>        </plugins>    </build></project>

注意spring-mvc-servlet.xml变化

spring-mvc-servlet.xml配置文件中，在mvc:annotation-driven元素中我注入一个GSONHttpMessageConverte类为Gson数据解析器，用于对Controller方法中返回的对象进行json数据解析。
记性好的同学，看到这里有没有仿佛见过的印象，是不是在前小结我们解决中文乱码的时候再也同样的位置注入一个spring mvc框架提供的StringHttpMessageConverter解析器用于解析字符串类型数据的。

起始简单理解，spring mvc在处理request、response的数据的时候，是通过不同的数据解析器来完成的。所以这里我们注入一个用Gson来处理request、response传递的数据Json化。

/framework_spring/src/main/resources/config/spring/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-4.2.xsd              http://www.springframework.org/schema/context              http://www.springframework.org/schema/context/spring-context-4.2.xsd             http://www.springframework.org/schema/mvc              http://www.springframework.org/schema/mvc/spring-mvc-4.2.xsd">    <!-- 开启spring 上下文注解支持 -->    <context:annotation-config />    <!-- 把标记了@Controller注解的类转换为bean -->    <context:component-scan base-package="cn.vfire.framework" />    <!-- 开启spring mvc注解支持 -->    <mvc:annotation-driven>        <mvc:message-converters register-defaults="true">            <bean class="cn.vfire.framework.spring.mvc.converter.GSONHttpMessageConverte">                <property name="excludeFieldsWithoutExposeAnnotation" value="false" />            </bean>        </mvc:message-converters>    </mvc:annotation-driven>    <!-- 如果当前请求为“/”时，则转发到“/helloworld/index” -->    <mvc:view-controller path="/" view-name="forward:/index.jsp" />     <!-- 设置默认的Servlet来响应静态文件 -->    <mvc:resources mapping="/resource" location="/resource" />    <!-- 当上面要访问的静态资源不包括在上面的配置中时，则根据此配置来访问 -->    <mvc:default-servlet-handler />    <!-- 启动Spring MVC的注解功能，完成请求和注解POJO的映射 -->    <bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" /></beans>

构造GSONHttpMessageConverte解析器

这个地方我就直接上代码了，这里需要强调一点，自定义的GSONHttpMessageConverte需要实现Spring mvc 提供的 AbstractHttpMessageConverter接口，由于Controller方法返回的树Mode对象，所以泛型我直接指定Object。

PS：别问我为什么我就知道这么写，请大家没事阅读一下Spring mvc提供的StringHttpMessageConverter解析器的源代码，基础好的同学照着写都可以写出来的，很好理解。
模仿：org.springframework.http.converter.StringHttpMessageConverter

在下面GSONHttpMessageConverte中，我预留出来四个成员属性
availableCharsets、excludeFieldsWithoutExposeAnnotation、dateFormat、writeAcceptCharset，
这几个成员属性都有对应的Setter方法，也就是说在注入GSONHttpMessageConverte对象的时候，可以直接利用spring输入属性值的方式修改默认值。（别问我这几个都是干啥的，自己读代码。）

cn.vfire.framework.spring.mvc.converter.GSONHttpMessageConverte

package cn.vfire.framework.spring.mvc.converter;import java.io.IOException;import java.lang.reflect.Type;import java.nio.charset.Charset;import java.util.ArrayList;import java.util.List;import lombok.Getter;import lombok.Setter;import org.springframework.http.HttpInputMessage;import org.springframework.http.HttpOutputMessage;import org.springframework.http.MediaType;import org.springframework.http.converter.AbstractHttpMessageConverter;import org.springframework.http.converter.HttpMessageNotReadableException;import org.springframework.http.converter.HttpMessageNotWritableException;import org.springframework.util.StreamUtils;import com.google.gson.Gson;import com.google.gson.GsonBuilder;import com.google.gson.reflect.TypeToken;public class GSONHttpMessageConverte extends AbstractHttpMessageConverter<Object> {    public static final Charset DEFAULT_CHARSET = Charset.forName("UTF-8");    public static final String DEFAULT_DATEFORMAT = "yyyy-MM-dd'T'HH:mm:ss.SSSZ";    private GsonBuilder gsonBuilder = new GsonBuilder();    @Getter    @Setter    private final Charset availableCharsets;    @Getter    @Setter    private boolean writeAcceptCharset = true;    @Getter    @Setter    private String dateFormat;    @Getter    @Setter    private boolean excludeFieldsWithoutExposeAnnotation = false;    public GSONHttpMessageConverte() {        this(DEFAULT_CHARSET);    }    public GSONHttpMessageConverte(Charset defaultCharset) {        super(new MediaType("application", "json", defaultCharset));        this.availableCharsets = DEFAULT_CHARSET;        this.dateFormat = DEFAULT_DATEFORMAT;    }    @Override    protected boolean supports(Class<?> clazz) {        return true;    }    @Override    protected Object readInternal(Class<? extends Object> clazz, HttpInputMessage inputMessage) throws IOException, HttpMessageNotReadableException {        Charset charset = this.getContentTypeCharset(inputMessage.getHeaders().getContentType());        return StreamUtils.copyToString(inputMessage.getBody(), charset);    }    @Override    protected void writeInternal(Object o, HttpOutputMessage outputMessage) throws IOException, HttpMessageNotWritableException {        if (this.writeAcceptCharset) {            outputMessage.getHeaders().setAcceptCharset(this.getAcceptedCharsets());        }        Charset charset = this.getContentTypeCharset(outputMessage.getHeaders().getContentType());        StreamUtils.copy(this.toJson(o), charset, outputMessage.getBody());    }    @Override    protected Long getContentLength(Object t, MediaType contentType) throws IOException {        return super.getContentLength(t, contentType);    }    private Charset getContentTypeCharset(MediaType contentType) {        if (contentType != null && contentType.getCharSet() != null) {            return contentType.getCharSet();        } else {            return this.availableCharsets;        }    }    protected List<Charset> getAcceptedCharsets() {        List<Charset> charsetList = new ArrayList<Charset>(1);        charsetList.add(this.availableCharsets);        return charsetList;    }    private String toJson(Object o) {        try {            if (this.excludeFieldsWithoutExposeAnnotation) {                this.gsonBuilder = this.gsonBuilder.excludeFieldsWithoutExposeAnnotation();            }            Type genericType = TypeToken.get(o.getClass()).getType();            Gson gson = gsonBuilder.setDateFormat(this.dateFormat).create();            String json = gson.toJson(o, genericType);            if (json == null || "".equals(json.trim())) {                json = "{}";            }            return json;        } catch (Exception e) {            e.printStackTrace();        }        return "";    }}

添加UserController的请求处理方法

直接上代码。在UserController中添加用于测试方法。为了和之前的区分访问URL我使用.json来控制。

@RequestMapping(path = "/userAdd.json", method = RequestMethod.POST, produces = "application/json; charset=UTF-8")    @ResponseBody    public Result userAddJson(UserMode user) {        XModelAndView modeView = new XModelAndView();        modeView.addObject("user", user);        System.out.println(String.format("添加用户%s完成", user.getName()));        return modeView.toResult();    }    @RequestMapping(path = "/userQuery.json", method = RequestMethod.GET, produces = "application/json; charset=UTF-8")    @ResponseBody    public Result userQueryJson(String username) {        XModelAndView modeView = new XModelAndView();        UserMode user = new UserMode();        {            user.setUsername(username);            user.setName("小红");            user.setAge(22);            user.setSex(0);        }        modeView.addObject("user", user);        System.out.println(String.format("查询用户名为%s用户 信息成功", user.getUsername()));        return modeView.toResult();    }

cn.vfire.framework.spring.mvc.controller.UserController

package cn.vfire.framework.spring.mvc.controller;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;import org.springframework.web.bind.annotation.ResponseBody;import org.springframework.web.bind.annotation.RestController;import cn.vfire.framework.spring.mvc.mode.UserMode;import cn.vfire.framework.spring.mvc.view.Result;import cn.vfire.framework.spring.mvc.view.XModelAndView;@RequestMapping("/api")@RestControllerpublic class UserController {    @RequestMapping(path = "/userAdd.api", method = RequestMethod.POST, produces = "application/json; charset=UTF-8")    @ResponseBody    public String userAdd(UserMode user) {        XModelAndView modeView = new XModelAndView();        modeView.addObject("user", user);        System.out.println(String.format("添加用户%s完成", user.getName()));        return modeView.toJson();    }    @RequestMapping(path = "/userQuery.api", method = RequestMethod.GET)    public String userQuery(String username) {        XModelAndView modeView = new XModelAndView();        UserMode user = new UserMode();        {            user.setUsername(username);            user.setName("小红");            user.setAge(22);            user.setSex(0);        }        modeView.addObject("user", user);        System.out.println(String.format("查询用户名为%s用户 信息成功", user.getUsername()));        return modeView.toJson();    }    @RequestMapping(path = "/userSave.api", method = RequestMethod.POST)    public String userSave(UserMode user) {        XModelAndView modeView = new XModelAndView();        user.setAge(23);        modeView.addObject("user", user);        System.out.println(String.format("更新用户名为%s用户信息成功", user.getUsername()));        return modeView.toJson();    }    @RequestMapping(path = "/userDel.api", method = RequestMethod.GET)    public String userDel(String username) {        XModelAndView modeView = new XModelAndView();        System.out.println(String.format("删除用户名为%s用户信息成功", username));        return modeView.toJson();    }    @RequestMapping(path = "/userAdd.json", method = RequestMethod.POST, produces = "application/json; charset=UTF-8")    @ResponseBody    public Result userAddJson(UserMode user) {        XModelAndView modeView = new XModelAndView();        modeView.addObject("user", user);        System.out.println(String.format("添加用户%s完成", user.getName()));        return modeView.toResult();    }    @RequestMapping(path = "/userQuery.json", method = RequestMethod.GET, produces = "application/json; charset=UTF-8")    @ResponseBody    public Result userQueryJson(String username) {        XModelAndView modeView = new XModelAndView();        UserMode user = new UserMode();        {            user.setUsername(username);            user.setName("小红");            user.setAge(22);            user.setSex(0);        }        modeView.addObject("user", user);        System.out.println(String.format("查询用户名为%s用户 信息成功", user.getUsername()));        return modeView.toResult();    }}

测试结果

URL 测试页面 测试结果 http://127.0.0.1:8000/api/userAdd.json http://127.0.0.1:8000/api/userQuery.json?username=xiaohong