Spring4.x中常用註解如@RequestMapping的使用
阿新 • • 發佈：2018-11-09
SpringMVC常用以下幾個註解：
表明這個類是SpringMVC裡的Controller,將其宣告為Spring的一個bean,Dispatcher Servlet會自動掃描註解了此註解的類，並將web請求對映到註解了@RequestMapping的方法上。
SpringMVC的核心註解,負責訪問的url與呼叫方法之間的對映;@RequestMapping可以放在類和方法上。註解在方法上的@RequestMapping路勁會繼承註解在類上的路勁。@RequestMapping支援Servelt的request和response作為引數，也支援對request和response的媒體型別進行配置。
@RequestMapping的屬性produces屬性控制response返回的形式;如Content-Type:text/plain; application/json等。
@RequestMapping的屬性method屬性控制接受訪問的型別,不寫不做限制
3.@ResponseBody
放在方法上或者返回值型別前，@ResponseBody支援將返回值放在response體內，而不是返回一個頁面。我們在很多基於Ajax的程式的時候，可以以此註解返回資料而不是頁面。
4.@RequestBody
放在方法引數前。@RequestBody允許請求的引數在request體內，而不是直接連結在地址後面。如下：
@PathVariable用來接收路勁引數。如/news/001,可接收001作為引數，此註解放在引數前。
這是個組合註解，組合了@Controller和@ResponseBody,這就意味著當你只開發一個和頁面互動資料的控制器的時候，只需要使用此註解即可。
關於上面註解的使用，程式碼示例如下：
一：新增依賴（完整的pom）
<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.flysun</groupId>
<artifactId>springmvc4</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>war</packaging>
<properties>
<!-- Generic properties -->
<java.version>1.7</java.version>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<!-- Web -->
<jsp.version>2.2</jsp.version>
<jstl.version>1.2</jstl.version>
<servlet.version>3.1.0</servlet.version>
<!-- Spring -->
<spring-framework.version>4.1.5.RELEASE</spring-framework.version>
<!-- Logging -->
<logback.version>1.0.13</logback.version>
<slf4j.version>1.7.5</slf4j.version>
</properties>
<dependencies>
<dependency>
<groupId>javax</groupId>
<artifactId>javaee-web-api</artifactId>
<version>7.0</version>
<scope>provided</scope>
</dependency>
<!-- Spring MVC -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>${spring-framework.version}</version>
</dependency>
<!-- 其他web依賴 -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
<version>${jstl.version}</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>${servlet.version}</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>jsp-api</artifactId>
<version>${jsp.version}</version>
<scope>provided</scope>
</dependency>
<!-- Spring and Transactions -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-tx</artifactId>
<version>${spring-framework.version}</version>
</dependency>
<!-- 使用SLF4J和LogBack作為日誌 -->
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>${slf4j.version}</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.16</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>jcl-over-slf4j</artifactId>
<version>${slf4j.version}</version>
</dependency>
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-classic</artifactId>
<version>${logback.version}</version>
</dependency>
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-core</artifactId>
<version>${logback.version}</version>
</dependency>
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-access</artifactId>
<version>${logback.version}</version>
</dependency>
<!--對json和xml格式的支援 -->
<dependency>
<groupId>com.fasterxml.jackson.dataformat</groupId>
<artifactId>jackson-dataformat-xml</artifactId>
<version>2.5.3</version>
</dependency>
<!-- file upload -->
<dependency>
<groupId>commons-fileupload</groupId>
<artifactId>commons-fileupload</artifactId>
<version>1.3.1</version>
</dependency>
<!-- 非必需，可簡化IO操作 -->
<dependency>
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>2.3</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>${spring-framework.version}</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.3.2</version>
<configuration>
<source>${java.version}</source>
<target>${java.version}</target>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<version>2.3</version>
<configuration>
<failOnMissingWebXml>false</failOnMissingWebXml>
</configuration>
</plugin>
</plugins>
</build>
</project><dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.5.3</version>
</dependency>二：傳值類Vo
public class DemoObj {
private Long id;
private String name;
//jackson對物件和json做轉換時一定需要此空構造
public DemoObj() {
super();
}
public DemoObj(Long id, String name) {
super();
this.id = id;
this.name = name;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}三：控制器類（分@Controller和@RestController）
[email protected]的控制器類
import javax.servlet.http.HttpServletRequest;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;
import com.wisely.highlight_springmvc4.domain.DemoObj;
@Controller // 1宣告此類為控制器
@RequestMapping("/anno") //2此類的訪問路勁為/anno 根地址為http://localhost:8080/spring4/anno
public class DemoAnnoController {
//此方法未標註路勁，因此使用類級別的路勁/anno
@RequestMapping(produces = "text/plain;charset=UTF-8",method = RequestMethod.GET)//宣告response的媒體型別和字符集
public @ResponseBody String index(HttpServletRequest request) { //引數可接收HttpServletRequest,當前也接收HttpServletResponse
//此處的@ResponseBody用在返回值前面
return "url:" + request.getRequestURL() + " can access";
}
//對映路勁http://.../anno/pathvar/123
@RequestMapping(value = "/pathvar/{str}", produces = "text/plain;charset=UTF-8")
public @ResponseBody String demoPathVar(@PathVariable String str, //接收路勁引數,引數名必須和{}中的保持一致
HttpServletRequest request) {
//上面的@PathVariable註解必須加上，否則str為空
return "url:" + request.getRequestURL() + " can access,str: " + str;
}
//接收路勁引數 對映路勁http://.../anno/requestParam?id=123
@RequestMapping(value = "/requestParam", produces = "text/plain;charset=UTF-8")
public @ResponseBody String passRequestParam(@RequestParam Long id,
HttpServletRequest request) {
//上面的@RequestParam可以加，也可以不加，都可以獲得引數id的值
return "url:" + request.getRequestURL() + " can access,id: " + id;
}
//演示引數到物件 對映路勁http://.../anno/obj?id=123&name=flysun
@RequestMapping(value = "/obj", produces = "application/json;charset=UTF-8")
@ResponseBody //@ResponseBody也可以用在方法上，上面的例子用在返回值前
public String passObj(DemoObj obj, HttpServletRequest request) {
return "url:" + request.getRequestURL()
+ " can access, obj id: " + obj.getId()+" obj name:" + obj.getName();
}
//演示不同的路勁到相同的方法上 對映路勁http://.../anno/name1 或者http://.../anno/name2
@RequestMapping(value = { "/name1", "/name2" }, produces = "text/plain;charset=UTF-8")
public @ResponseBody String remove(HttpServletRequest request) {
return "url:" + request.getRequestURL() + " can access";
}
}[email protected]的控制器類
@RestController //宣告是控制器，並且返回的資料不需要加@ResponseBody
@RequestMapping("/rest")
public class DemoRestController {
@RequestMapping(value = "/getjson",
produces={"application/json;charset=UTF-8"}) //返回的資料型別是json
public DemoObj getjson (@RequestBody DemoObj obj){
return new DemoObj(obj.getId()+1, obj.getName()+"yy");//直接返回物件，物件會自動轉換為json
}
@RequestMapping(value = "/getxml",
produces={"application/xml;charset=UTF-8"})//返回的資料型別是xml
public DemoObj getxml(DemoObj obj){
return new DemoObj(obj.getId()+1, obj.getName()+"yy");//直接返回物件，物件會自動轉換為xml
}
}