Spring4.1新特性——Spring MVC加強

時間 2019-11-06

標籤 spring4.1 spring 特性 mvc 加強欄目 Spring 简体版

原文原文鏈接

一、GroovyWebApplicationContext html

在Spring 4.1以前沒有提供Web集成的ApplicationContext，在《Spring4新特性——Groovy Bean定義DSL》中咱們本身去實現的com.sishuok.spring4.context.support.WebGenricGroovyApplicationContext，而4.1其已經提供了相應實現，直接把《Spring4新特性——Groovy Bean定義DSL》配置中的相應類改掉便可。java

二、視圖解析器標籤git

以前咱們都是這樣定義視圖解析器：github

Java代碼 web

<bean id="mvcVelocityEngine" class="org.springframework.web.servlet.view.velocity.VelocityConfigurer"> spring
<property name="resourceLoaderPath" value="/WEB-INF/vm/,classpath:com/github/zhangkaitao" /> json
</bean> 安全
<bean id="viewResolver" class="org.springframework.web.servlet.view.velocity.VelocityViewResolver"> mvc
<property name="prefix" value=""/> app
<property name="suffix" value=".vm"/>
<property name="cache" value="false"/>
</bean>

    <bean id="mvcVelocityEngine" class="org.springframework.web.servlet.view.velocity.VelocityConfigurer">
        <property name="resourceLoaderPath" value="/WEB-INF/vm/,classpath:com/github/zhangkaitao" />
    </bean>
    <bean id="viewResolver" class="org.springframework.web.servlet.view.velocity.VelocityViewResolver">
        <property name="prefix" value=""/>
        <property name="suffix" value=".vm"/>
        <property name="cache" value="false"/>
    </bean>

而如今咱們可使用MVC標籤訂義：

Java代碼

<mvc:velocity-configurer resource-loader-path="/WEB-INF/vm/,classpath:com/github/zhangkaitao"/>
<mvc:view-resolvers>
<mvc:velocity cache-views="false" prefix="" suffix=".vm"/>
</mvc:view-resolvers>

    <mvc:velocity-configurer resource-loader-path="/WEB-INF/vm/,classpath:com/github/zhangkaitao"/>
    <mvc:view-resolvers>
        <mvc:velocity cache-views="false" prefix="" suffix=".vm"/>
    </mvc:view-resolvers>

再來看一個更復雜的例子：

Java代碼

<mvc:velocity-configurer resource-loader-path="/WEB-INF/vm/,classpath:com/github/zhangkaitao"/>
<mvc:groovy-configurer resource-loader-path="classpath:templates/" cache-templates="false"/>
<mvc:view-resolvers>
<mvc:content-negotiation>
<mvc:default-views>
<bean class="org.springframework.web.servlet.view.json.MappingJackson2JsonView">
<property name="jsonpParameterNames">
<set>
<value>jsonp</value>
<value>callback</value>
</set>
</property>
</bean>
</mvc:default-views>
</mvc:content-negotiation>
<mvc:velocity cache-views="false" prefix="" suffix=".vm"/>
<mvc:groovy cache-views="false" suffix=".tpl"/>
</mvc:view-resolvers>

    <mvc:velocity-configurer resource-loader-path="/WEB-INF/vm/,classpath:com/github/zhangkaitao"/>
    <mvc:groovy-configurer resource-loader-path="classpath:templates/" cache-templates="false"/>
    <mvc:view-resolvers>
        <mvc:content-negotiation>
            <mvc:default-views>
                <bean class="org.springframework.web.servlet.view.json.MappingJackson2JsonView">
                    <property name="jsonpParameterNames">
                        <set>
                            <value>jsonp</value>
                            <value>callback</value>
                        </set>
                    </property>
                </bean>
            </mvc:default-views>
        </mvc:content-negotiation>
        <mvc:velocity cache-views="false" prefix="" suffix=".vm"/>
        <mvc:groovy cache-views="false" suffix=".tpl"/>
    </mvc:view-resolvers>

mvc:content-negotiation用於定義內容協商的視圖解析器，且內部能夠定義默認視圖；而後咱們又定義了mvc:velocity和mvc:groovy兩個視圖解析器；它們會按照順序進行解析。另外幾個視圖解析器是：

mvc:freemarker

mvc:bean-name

mvc:jsp

這種方式有一個很大的問題就是隻能作默認配置，若是想自定義其屬性值就搞不定了，估計當時開發的人考慮不全或沒有經驗。

三、控制器標籤

Spring 4.1提供了更豐富的控制器標籤：

3.一、重定向視圖控制器標籤

Java代碼

<mvc:redirect-view-controller
path="/redirect"
redirect-url="/status"
context-relative="true"
status-code="301"
keep-query-params="true"/>

    <mvc:redirect-view-controller
            path="/redirect"
            redirect-url="/status"
            context-relative="true"
            status-code="301"
            keep-query-params="true"/>

3.二、狀態控制器標籤

Java代碼

<mvc:status-controller path="/status" status-code="200"/>

    <mvc:status-controller path="/status" status-code="200"/>

3.三、帶狀態的視圖控制器標籤

Java代碼

<mvc:view-controller path="/error/**" status-code="200"/>

    <mvc:view-controller path="/error/**" status-code="200"/>

四、Groovy Template引擎集成

Spring 4.1提供了對Groovy Template模板引擎的集成，其是一種DSL風格的模板引擎，其也是最先在Spring Boot中引入的。

4.一、Spring配置文件

Java代碼

<mvc:groovy-configurer resource-loader-path="classpath:templates/" cache-templates="false"/>
<mvc:view-resolvers>
<mvc:groovy cache-views="false" suffix=".tpl"/>
</mvc:view-resolvers>

    <mvc:groovy-configurer resource-loader-path="classpath:templates/" cache-templates="false"/>
    <mvc:view-resolvers>
        <mvc:groovy cache-views="false" suffix=".tpl"/>
    </mvc:view-resolvers>

4.二、模板heelo.tpl

Java代碼

yieldUnescaped '<!DOCTYPE html>'
html {
head {
title('hello groovy templates')
}
body {
div("hello $user.name")
}
}

yieldUnescaped '<!DOCTYPE html>'
html {
  head {
    title('hello groovy templates')
  }
  body {
      div("hello $user.name")
  }
}

具體語法請參考官方文檔。

五、 Jackson @JsonView支持

可使用@JsonView來分組渲染JSON數據，按需展現JSON數據。

5.一、模型

Java代碼

public class User implements Serializable {
public static interface OnlyIdView {}
public static interface OnlyNameView {}
public static interface AllView extends OnlyIdView, OnlyNameView {}
@JsonView(OnlyIdView.class)
private Long id;
@JsonView(OnlyNameView.class)
private String name;
……
}

public class User implements Serializable {
    public static interface OnlyIdView {}
    public static interface OnlyNameView {}
    public static interface AllView extends OnlyIdView, OnlyNameView {}

    @JsonView(OnlyIdView.class)
    private Long id;

    @JsonView(OnlyNameView.class)
    private String name;  
    ……
}

定義了三個視圖：OnlyIdView、OnlyNameView和AllView。

5.二、控制器

Java代碼

@RestController
public class JacksonJsonViewController {
@RequestMapping("/jackson1")
@JsonView(User.OnlyIdView.class)
public User test1() {
return new User(1L, "zhangsan");
}
@RequestMapping("/jackson2")
@JsonView(User.OnlyNameView.class)
public User test2() {
return new User(1L, "zhangsan");
}
@RequestMapping("/jackson3")
@JsonView(User.AllView.class) //能夠省略
public User test3() {
return new User(1L, "zhangsan");
}
}

@RestController
public class JacksonJsonViewController {

    @RequestMapping("/jackson1")
    @JsonView(User.OnlyIdView.class)
    public User test1() {
        return new User(1L, "zhangsan");
    }

    @RequestMapping("/jackson2")
    @JsonView(User.OnlyNameView.class)
    public User test2() {
        return new User(1L, "zhangsan");
    }

    @RequestMapping("/jackson3")
    @JsonView(User.AllView.class) //能夠省略
    public User test3() {
        return new User(1L, "zhangsan");
    }
}

使用@JsonView控制渲染哪些數據。

六、Jsonp支持

6.一、MappingJackson2JsonView提供的支持

Java代碼

<bean class="org.springframework.web.servlet.view.json.MappingJackson2JsonView">
<property name="jsonpParameterNames">
<set>
<value>jsonp</value>
<value>callback</value>
</set>
</property>
</bean>

    <bean class="org.springframework.web.servlet.view.json.MappingJackson2JsonView">
        <property name="jsonpParameterNames">
            <set>
                <value>jsonp</value>
                <value>callback</value>
            </set>
       </property>
    </bean>

而後訪問如http://localhost:8080/json?callback=callback便可獲得JSONP響應：callback({"user":{"id":1,"name":"zhangsan"}});。

6.二、對使用HttpMessageConverter的@ResponseBody的支持

Java代碼

@Order(2)
@ControllerAdvice(basePackages = "com.github")
public class JsonpAdvice extends AbstractJsonpResponseBodyAdvice {
public JsonpAdvice() {
super("callback", "jsonp"); //指定jsonpParameterNames
}
}

@Order(2)
@ControllerAdvice(basePackages = "com.github")
public class JsonpAdvice extends AbstractJsonpResponseBodyAdvice {
    public JsonpAdvice() {
        super("callback", "jsonp"); //指定jsonpParameterNames
    }
}

訪問http://localhost:8080/jackson1?callback=callback便可看到JSONP響應。

@ContollerAdvice的做用請參考《Spring3.2新註解@ControllerAdvice》，basePackages用於指定對哪些包裏的Controller起做用。

6.三、ResponseBodyAdvice

咱們以前實現的JsonpAdvice其繼承自AbstractJsonpResponseBodyAdvice，而AbstractJsonpResponseBodyAdvice繼承自ResponseBodyAdvice，其做用是在響應體寫出以前作一些處理：

Java代碼

@Order(1)
@ControllerAdvice(basePackages = "com.github")
public class MyResponseBodyAdvice implements ResponseBodyAdvice<Object> {
@Override
public boolean supports(MethodParameter methodParameter, Class<? extends HttpMessageConverter<?>> converterType) {
return methodParameter.getMethod().getReturnType().isAssignableFrom(User.class);
}
@Override
public Object beforeBodyWrite(
Object obj, MethodParameter methodParameter, MediaType mediaType,
Class<? extends HttpMessageConverter<?>> converterType,
ServerHttpRequest serverHttpRequest, ServerHttpResponse serverHttpResponse) {
User user = ((User)obj);
user.setName("---" + user.getName() + "---");
return user;
}
}

@Order(1)
@ControllerAdvice(basePackages = "com.github")
public class MyResponseBodyAdvice implements ResponseBodyAdvice<Object> {

    @Override
    public boolean supports(MethodParameter methodParameter, Class<? extends HttpMessageConverter<?>> converterType) {
        return methodParameter.getMethod().getReturnType().isAssignableFrom(User.class);
    }

    @Override
    public Object beforeBodyWrite(
            Object obj, MethodParameter methodParameter, MediaType mediaType,
            Class<? extends HttpMessageConverter<?>> converterType,
            ServerHttpRequest serverHttpRequest, ServerHttpResponse serverHttpResponse) {

        User user = ((User)obj);
        user.setName("---" + user.getName() + "---");
        return user;
    }
}

一、supports指定支持哪些類型的方法進行處理，此處是返回值爲User的；二、咱們獲得User對象而後在名字先後拼上」---「；三、能夠指定多個ResponseBodyAdvice，使用@Order指定順序。訪問http://localhost:8080/jackson2?callback=callback能夠看到效果。

七、Gson HttpMessageConverter

7.一、Spring配置

Java代碼

<mvc:annotation-driven>
<mvc:message-converters>
<bean class="org.springframework.http.converter.json.GsonHttpMessageConverter"/>
</mvc:message-converters>
</mvc:annotation-driven>

    <mvc:annotation-driven>
        <mvc:message-converters>
            <bean class="org.springframework.http.converter.json.GsonHttpMessageConverter"/>
        </mvc:message-converters>
    </mvc:annotation-driven>

使用方式和Jackson Json相似。本文使用的是<gson.version>2.2.4</gson.version>版本。

八、Protobuf HttpMessageConverter

8.一、Spring配置

Java代碼

<mvc:annotation-driven>
<mvc:message-converters>
<bean class="org.springframework.http.converter.protobuf.ProtobufHttpMessageConverter">
<constructor-arg>
<bean class="com.github.zhangkaitao.web.controller.MyExtensionRegistryInitializer"/>
</constructor-arg>
</bean>
</mvc:message-converters>
</mvc:annotation-driven>

    <mvc:annotation-driven>
        <mvc:message-converters>
            <bean class="org.springframework.http.converter.protobuf.ProtobufHttpMessageConverter">
                <constructor-arg>
                    <bean class="com.github.zhangkaitao.web.controller.MyExtensionRegistryInitializer"/>
                </constructor-arg>
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>

8.二、定義protobuf message（proto/user.proto）

Java代碼

package com.github.zhangkaitao.pb;
option java_package = "com.github.zhangkaitao.pb";
option java_outer_classname = "UserProtos";
message User {
optional int64 id = 1;
optional string name = 2;
}

package com.github.zhangkaitao.pb;
 
 option java_package = "com.github.zhangkaitao.pb";
 option java_outer_classname = "UserProtos";
 
 message User {
   optional int64 id = 1;
   optional string name = 2;
 }

8.三、添加maven插件自動把protobuf message轉化成Java代碼

Java代碼

<plugin>
<groupId>com.google.protobuf.tools</groupId>
<artifactId>maven-protoc-plugin</artifactId>
<version>0.1.10</version>
<executions>
<execution>
<id>generate-sources</id>
<goals>
<goal>compile</goal>
</goals>
<phase>generate-sources</phase>
<configuration>
<protoSourceRoot>${basedir}/src/main/proto/</protoSourceRoot>
<includes>
<param>**/*.proto</param>
</includes>
</configuration>
</execution>
</executions>
<configuration>
<protocExecutable>D:/software/protoc.exe</protocExecutable>
</configuration>
</plugin>

            <plugin>
                <groupId>com.google.protobuf.tools</groupId>
                <artifactId>maven-protoc-plugin</artifactId>
                <version>0.1.10</version>
                <executions>
                    <execution>
                        <id>generate-sources</id>
                        <goals>
                            <goal>compile</goal>
                        </goals>
                        <phase>generate-sources</phase>
                        <configuration>
                            <protoSourceRoot>${basedir}/src/main/proto/</protoSourceRoot>
                            <includes>
                                <param>**/*.proto</param>
                            </includes>
                        </configuration>
                    </execution>
                </executions>
                <configuration>
                    <protocExecutable>D:/software/protoc.exe</protocExecutable>
                </configuration>
            </plugin>

8.四、測試控制器

Java代碼

@RestController
public class ProtobufController {
@RequestMapping("/proto/read")
public ResponseEntity<UserProtos.User> protoRead() {
return ResponseEntity.ok(UserProtos.User.newBuilder().setId(1).setName("zhangsan").build());
}
@RequestMapping("/proto/write")
public ResponseEntity<UserProtos.User> protoRead(RequestEntity<UserProtos.User> requestEntity) {
System.out.println("server===\n" + requestEntity.getBody());
return ResponseEntity.ok(requestEntity.getBody());
}
}

@RestController
public class ProtobufController {
    @RequestMapping("/proto/read")
    public ResponseEntity<UserProtos.User> protoRead() {
        return ResponseEntity.ok(UserProtos.User.newBuilder().setId(1).setName("zhangsan").build());
    }
    @RequestMapping("/proto/write")
    public ResponseEntity<UserProtos.User> protoRead(RequestEntity<UserProtos.User> requestEntity) {
        System.out.println("server===\n" + requestEntity.getBody());
        return ResponseEntity.ok(requestEntity.getBody());
    }
}

8.五、測試用例（com.github.zhangkaitao.proto.ProtoTest）

Java代碼

@Test
public void testRead() {
HttpHeaders headers = new HttpHeaders();
RequestEntity<UserProtos.User> requestEntity =
new RequestEntity<UserProtos.User>(headers, HttpMethod.POST, URI.create(baseUri + "/proto/read"));
ResponseEntity<UserProtos.User> responseEntity =
restTemplate.exchange(requestEntity, UserProtos.User.class);
System.out.println(responseEntity.getBody());
}
@Test
public void testWrite() {
UserProtos.User user = UserProtos.User.newBuilder().setId(1).setName("zhangsan").build();
HttpHeaders headers = new HttpHeaders();
RequestEntity<UserProtos.User> requestEntity =
new RequestEntity<UserProtos.User>(user, headers, HttpMethod.POST, URI.create(baseUri + "/proto/write"));
ResponseEntity<UserProtos.User> responseEntity =
restTemplate.exchange(requestEntity, UserProtos.User.class);
System.out.println(responseEntity.getBody());
}

    @Test
    public void testRead() {
        HttpHeaders headers = new HttpHeaders();
        RequestEntity<UserProtos.User> requestEntity =
                new RequestEntity<UserProtos.User>(headers, HttpMethod.POST, URI.create(baseUri + "/proto/read"));

        ResponseEntity<UserProtos.User> responseEntity =
                restTemplate.exchange(requestEntity, UserProtos.User.class);

        System.out.println(responseEntity.getBody());
    }

    @Test
    public void testWrite() {
        UserProtos.User user = UserProtos.User.newBuilder().setId(1).setName("zhangsan").build();
        HttpHeaders headers = new HttpHeaders();
        RequestEntity<UserProtos.User> requestEntity =
                new RequestEntity<UserProtos.User>(user, headers, HttpMethod.POST, URI.create(baseUri + "/proto/write"));

        ResponseEntity<UserProtos.User> responseEntity =
                restTemplate.exchange(requestEntity, UserProtos.User.class);
        System.out.println(responseEntity.getBody());
    }

測試用例知識請參考《Spring MVC測試框架詳解——服務端測試》和《Spring MVC測試框架詳解——客戶端測試》。

測試過程當中會拋出：

Java代碼

Caused by: java.lang.UnsupportedOperationException
at java.util.Collections$UnmodifiableMap.put(Collections.java:1342)
at org.springframework.http.HttpHeaders.set(HttpHeaders.java:869)
at org.springframework.http.converter.protobuf.ProtobufHttpMessageConverter.setProtoHeader(ProtobufHttpMessageConverter.java:196)

Caused by: java.lang.UnsupportedOperationException
	at java.util.Collections$UnmodifiableMap.put(Collections.java:1342)
	at org.springframework.http.HttpHeaders.set(HttpHeaders.java:869)
	at org.springframework.http.converter.protobuf.ProtobufHttpMessageConverter.setProtoHeader(ProtobufHttpMessageConverter.java:196)

這是由於ProtobufHttpMessageConverter會修改響應頭，可是ResponseEntity構造時HttpHeaders是不容許修改的。暫時解決辦法是註釋掉：

Java代碼

//setProtoHeader(outputMessage, message);

//setProtoHeader(outputMessage, message);

九、RequestEntity/ResponseEntity

Spring 4.1提供了ResponseEntity配對的RequestEntity，使用方式和HttpEntity同樣。具體能夠參考com.github.zhangkaitao.web.controller.RequestResponseEntityController。

十、MvcUriComponentsBuilder

其做用能夠參考《Spring4新特性——註解、腳本、任務、MVC等其餘特性改進》，Spring 4.1又提供了一個新的方法MvcUriComponentsBuilder.fromMappingName用於根據控制器方法來生成請求URI。

Java代碼

@RestController
public class MvcUriComponentsBuilderController {
@RequestMapping("/uri")
public String mvcUriComponentsBuilder1() {
return MvcUriComponentsBuilder.fromMappingName("MUCBC#mvcUriComponentsBuilder1").build();
}
@RequestMapping("/uri/{id}")
public String mvcUriComponentsBuilder2(@PathVariable Long id) {
return MvcUriComponentsBuilder.fromMappingName("MUCBC#mvcUriComponentsBuilder2").arg(0, "123").build();
}
}

@RestController
public class MvcUriComponentsBuilderController {

    @RequestMapping("/uri")
    public String mvcUriComponentsBuilder1() {
        return MvcUriComponentsBuilder.fromMappingName("MUCBC#mvcUriComponentsBuilder1").build();
    }
    @RequestMapping("/uri/{id}")
    public String mvcUriComponentsBuilder2(@PathVariable Long id) {
        return MvcUriComponentsBuilder.fromMappingName("MUCBC#mvcUriComponentsBuilder2").arg(0, "123").build();
    }
}

規則是「控制器全部大寫字母#方法名」找到相應的方法。另外能夠直接在頁面中使用以下方式獲取相應的URI：

Java代碼

${s:mvcUrl('MUCBC#mvcUriComponentsBuilder2').arg(0,"123").build()}

${s:mvcUrl('MUCBC#mvcUriComponentsBuilder2').arg(0,"123").build()}

如上方式只能在正常EL 3.0的容器中運行，可參考《Expression Language 3.0新特性》。

十一、MockRestServiceServer

MockRestServiceServer目前提供了對AsyncRestTemplate的支持，使用方式和RestTemplate同樣。可參考《Spring MVC測試框架詳解——客戶端測試》。

十二、MockMvcConfigurer

Spring 4.1提供了MockMvcConfigurer用於進行一些通用配置，使用方式以下：

Java代碼

mockMvc = MockMvcBuilders.webAppContextSetup(context).apply(defaultSetup()).build();

mockMvc = MockMvcBuilders.webAppContextSetup(context).apply(defaultSetup()).build();

MockMvcConfigurer實現：

Java代碼

private MockMvcConfigurer defaultSetup() {
return new MockMvcConfigurer() {
@Override
public void afterConfigurerAdded(ConfigurableMockMvcBuilder<?> configurableMockMvcBuilder) {
configurableMockMvcBuilder.alwaysExpect(status().isOk());
}
@Override
public RequestPostProcessor beforeMockMvcCreated(ConfigurableMockMvcBuilder<?> configurableMockMvcBuilder, WebApplicationContext webApplicationContext) {
return new RequestPostProcessor() {
@Override
public MockHttpServletRequest postProcessRequest(MockHttpServletRequest mockHttpServletRequest) {
mockHttpServletRequest.setAttribute("aa", "aa");
return mockHttpServletRequest;
}
};
}
};
}

    private MockMvcConfigurer defaultSetup() {
        return new MockMvcConfigurer() {
            @Override
            public void afterConfigurerAdded(ConfigurableMockMvcBuilder<?> configurableMockMvcBuilder) {
                configurableMockMvcBuilder.alwaysExpect(status().isOk());
            }
            @Override
            public RequestPostProcessor beforeMockMvcCreated(ConfigurableMockMvcBuilder<?> configurableMockMvcBuilder, WebApplicationContext webApplicationContext) {
                return new RequestPostProcessor() {
                    @Override
                    public MockHttpServletRequest postProcessRequest(MockHttpServletRequest mockHttpServletRequest) {
                        mockHttpServletRequest.setAttribute("aa", "aa");
                        return mockHttpServletRequest;
                    }
                };
            }
        };
    }

能夠在如上實現中進行一些通用配置，如安全（往Request中扔安全對象之類的）。測試用例可參考com.github.zhangkaitao.proto.ProtoTest2。

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