搭建 Spring MVC 接口环境
1、maven构建项目，pom.xml文件
<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.loong</groupId>
<artifactId>loong</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>war</packaging>
<name>loong</name>
<url>http://maven.apache.org</url>
<!-- 获取架包的版本 -->
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<spring.version>3.2.5.RELEASE</spring.version>
<log4j.version>1.2.17</log4j.version>
<jackson.version>1.9.13</jackson.version>
</properties>
<dependencies>
<!-- Spring MVC使用的架包 -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>${spring.version}</version>
</dependency>
<!-- 日志 -->
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>${log4j.version}</version>
</dependency>
<!-- Json解析 -->
<dependency>
<groupId>org.codehaus.jackson</groupId>
<artifactId>jackson-mapper-asl</artifactId>
<version>${jackson.version}</version>
</dependency>
</dependencies>
</project>
2、配置web.xml（webapp/WEB-INF/web.xml）
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0"> <display-name>loong</display-name> <welcome-file-list> <welcome-file>index.html</welcome-file> </welcome-file-list> <!-- Spring MVN 配置 --> <servlet> <servlet-name>mvc</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <init-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:context/app.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>mvc</servlet-name> <url-pattern>*.json</url-pattern> </servlet-mapping> <!-- 编码处理 --> <filter> <filter-name>encoding</filter-name> <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class> <init-param> <param-name>encoding</param-name> <param-value>UTF-8</param-value> </init-param> </filter> <filter-mapping> <filter-name>encoding</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <!-- 日志 --> <listener> <listener-class>org.springframework.web.util.Log4jConfigListener</listener-class> </listener> <context-param> <param-name>log4jConfigLocation</param-name> <param-value>classpath:properties/log4j.properties</param-value> </context-param> </web-app>
3、Spring配置（resources/context/app.xml）
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.springframework.org/schema/beans" 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-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.xsd"> <!-- 扫描注释 --> <context:component-scan base-package="com.loong" /> <!-- 开启mvn --> <mvc:annotation-driven /> <!-- mvc配置 --> <!-- <import resource="app-mvc.xml" /> --> </beans>
4、log4j日志配置（resources/properties/log4j.properties）
log4j.rootLogger=info,C,I,E
#Console appender
log4j.appender.C.Threshold=info
log4j.appender.C=org.apache.log4j.ConsoleAppender
log4j.appender.C.layout=org.apache.log4j.PatternLayout
log4j.appender.C.layout.ConversionPattern=%m%n
#InfoFile appender
log4j.appender.I.Threshold=info
log4j.appender.I=org.apache.log4j.DailyRollingFileAppender
log4j.appender.I.file=${catalina.base}/logs/log.log
log4j.appender.I.layout=org.apache.log4j.PatternLayout
log4j.appender.I.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} [%t][%C:%L(%M)] - %m%n
#ErrorFile appender
log4j.appender.E.Threshold=error
log4j.appender.E=org.apache.log4j.DailyRollingFileAppender
log4j.appender.E.file=${catalina.base}/logs/error.log
log4j.appender.E.layout=org.apache.log4j.PatternLayout
log4j.appender.E.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} [%t][%C:%L(%M)] - %m%n
5、新建一个测试类
@Controller
@RequestMapping("demo")
public class DemoResource {
@RequestMapping("test")
@ResponseBody
public DemoResult test(DemoParam param) {
DemoResult result = new DemoResult();
result.setSucc(0);
result.setData(param);
return result;
}
}
访问参数JavaBean：
public class DemoParam {
private String param;
public String getParam() {
return param;
}
public void setParam(String param) {
this.param = param;
}
}
返回参数JavaBean：
public class DemoResult {
private Integer succ;
private String message;
private Object data;
public Integer getSucc() {
return succ;
}
public void setSucc(Integer succ) {
this.succ = succ;
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
public Object getData() {
return data;
}
public void setData(Object data) {
this.data = data;
}
}
启动项目，访问 localhost:8080/loong/demo/test.json?param=1，返回：{"succ":0,"message":null,"data":{"param":"1"}}，测试成功。
Spring MVC常用注释：
@RequestMapping 映射地址
@ResponseBody 声明返回对象作为响应正文
@RequestBody 声明正文作为请求参数（一般访问参数是个复杂对象时会用到）
@ControllerAdvice 声明是控制器
@ExceptionHandler 异常拦截
@InitBinder 请求初始化处理
备忘下：Spring的类注释：@Controller（接口层）、@Service（服务层）、@Repository（持久层）、@Component（组件）
6、去除JavaBean中字段返回
修改一下返回的Bean：
@JsonSerialize(include = JsonSerialize.Inclusion.NON_NULL)
public class DemoResult {
@JsonIgnore
private Integer succ;
private String message;
private Object data;
public Integer getSucc() {
return succ;
}
public void setSucc(Integer succ) {
this.succ = succ;
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
public Object getData() {
return data;
}
public void setData(Object data) {
this.data = data;
}
}
再测试下访问 localhost:8080/loong/demo/test.json?param=1，返回：{"data":{"param":"1"}}。
其中：
@JsonSerialize 定义转换的过滤规则，JsonSerialize.Inclusion.NON_NULL 会过滤为空的对象。
@JsonIgnore 被声明的变量会直接被过滤掉。
7、增加异常处理
新增一个异常处理类：
/**
* 接口异常处理器
*
* @author 张成轩
*/
@ControllerAdvice
public class RestExceptionHandler {
/**
* 运行时异常处理
*
* @param ex 异常对象
* @return vo
*/
@ExceptionHandler(RuntimeException.class)
@ResponseBody
public DemoResult runtimeExceptionHandler(RuntimeException ex) {
DemoResult result = new DemoResult();
result.setSucc(-1);
result.setMessage(ex.getMessage());
return result;
}
/**
* 通用异常处理
*
* @param ex 异常对象
* @return vo
*/
@ExceptionHandler(Exception.class)
@ResponseBody
public DemoResult exceptionHandler(Exception ex) {
DemoResult result = new DemoResult();
result.setSucc(-2);
result.setMessage(ex.getMessage());
return result;
}
}
修改一下测试类：
public DemoResult test(DemoParam param) {
if(param.getParam() == null){
throw new RuntimeException("异常:访问参数为空");
}
......
}
测试一下，localhost:8080/loong/demo/test.json，返回：{"succ":-1,"message":"异常:访问参数为空","data":null}。
8、增加访问初始化处理
新增一个访问初始化类
/**
* 接口访问初始化处理器
*
* @author 张成轩
*/
@ControllerAdvice
public class RestInitHandler {
/**
* 接口访问参数初始化
*
* @param binder
* @param request
*/
@InitBinder
public void beforeHandle(WebDataBinder binder, WebRequest request) {
}
}
9、新增Jsonp处理
新增Jsonp处理类：
/**
* JsonP处理器
*
* @author 张成轩
*/
public class JsonpHandler extends MappingJacksonHttpMessageConverter {
/** 回调参数 */
private final static String CALLBACK = "callback";
/** Jsonp起始 */
private final static String START = "(";
/** Jsonp终止 */
private final static String END = "); ";
@Override
protected void writeInternal(Object o, HttpOutputMessage outputMessage) throws IOException,
HttpMessageNotWritableException {
JsonEncoding encoding = getJsonEncoding(outputMessage.getHeaders().getContentType());
// 获取Json构造对象
JsonGenerator jsonGenerator = getObjectMapper().getJsonFactory().createJsonGenerator(
outputMessage.getBody(), encoding);
try {
HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder
.currentRequestAttributes()).getRequest();
// 获取回调方法名
String callback = request.getParameter(CALLBACK);
if (callback == null || callback.trim().isEmpty()) {
// 正常方式
getObjectMapper().writeValue(jsonGenerator, o);
} else {
// 写回调Js信息
jsonGenerator.writeRaw(callback);
jsonGenerator.writeRaw(START);
getObjectMapper().writeValue(jsonGenerator, o);
jsonGenerator.writeRaw(END);
}
jsonGenerator.flush();
} catch (JsonProcessingException e) {
throw new HttpMessageNotWritableException(e.getMessage(), e);
}
}
}
修改一下Spring配置文件，（resources/context/app.xml）
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.springframework.org/schema/beans" 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-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.xsd"> <!-- 扫描注释 --> <context:component-scan base-package="com.loong" /> <!-- 开启mvn --> <mvc:annotation-driven content-negotiation-manager="contentNegotiationManager"> <mvc:message-converters> <bean class="com.loong.handler.JsonpHandler" /> </mvc:message-converters> </mvc:annotation-driven> <bean id="contentNegotiationManager" class="org.springframework.web.accept.ContentNegotiationManagerFactoryBean"> <property name="favorPathExtension" value="true" /> <property name="favorParameter" value="true" /> <property name="ignoreAcceptHeader" value="true" /> <property name="defaultContentType" value="application/json;charset=UTF-8" /> <property name="parameterName" value="dataType" /> <property name="mediaTypes"> <map> <entry key="json" value="application/json;charset=UTF-8" /> <entry key="jsonp" value="application/x-javascript;charset=UTF-8" /> <entry key="xml" value="application/xml;charset=UTF-8" /> <entry key="html" value="text/html;charset=UTF-8" /> </map> </property> </bean> </beans>
maven里引入一下servlet架包
<!-- servlet --> <dependency> <groupId>javax.servlet</groupId> <artifactId>servlet-api</artifactId> <version>2.5</version> <scope>provided</scope> </dependency>
测试下
访问：localhost:8080/loong/demo/test.json?param=1&callback=test，返回：test({"succ":0,"message":null,"data":{"param":"1"}});。
访问：localhost:8080/loong/demo/test.json?param=1，返回：{"succ":0,"message":null,"data":{"param":"1"}}。