是一套规则，不同的系统之间（Vue java Python C# PHP）具体四种不同类型的HTTP 请求分别表示四种基本操作（CRUD）
GET ：查询（R）
POST：添加（C）
PUT：修改（U）
DELETE：删除（D）
Spring MVC 默认支持RESTful 结构
RestHandler.java
package com.xcl.controller;import com.xcl.entity.User;
import com.xcl.repository.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;import javax.servlet.http.HttpServletResponse;
import java.util.Collection;@RestController
@RequestMapping("/rest")
public class RestHandler { @Autowired
private UserRepository userRepository; /**
* 查询所有 GET请求
*
* @param response
* @return
*/
@GetMapping("/findAll")
public Collection<User> findAll(HttpServletResponse response) {
response.setContentType("text/json;charset=UTF-8");
return userRepository.findAll();
} /**
* 根据ID查询 GET请求
*
* @param response
* @param id
* @return
*/
@GetMapping("/findById/{id}")
public User findAll(HttpServletResponse response, @PathVariable("id") Integer id) {
response.setContentType("text/json;charset=UTF-8");
return userRepository.findById(id);
} /**
* 添加 POST请求
*
* @param user
*/
@PostMapping("/save")
public void save(User user) {
userRepository.saveOrUpdate(user);
} /**
* 修改 PUT请求
*
* @param user
*/
@PutMapping("/update")
public void update(User user) {
userRepository.saveOrUpdate(user);
} /**
* 删除 DELETE请求
*
* @param id
*/
@DeleteMapping("/delete/{id}")
public void deleteById(@PathVariable("id") Integer id) {
userRepository.deleteById(id);
}
}
User.java
package com.xcl.entity;import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
private Integer id;
private String name;
}
UserRepository 接口
package com.xcl.repository;import com.xcl.entity.User;import java.util.Collection;public interface UserRepository {
public Collection<User> findAll();
public User findById(Integer id);
public void saveOrUpdate(User user);
public void deleteById(Integer id);
}
UserRepositoryImpl 实现类
package com.xcl.repository.Impl;import com.xcl.entity.User;
import com.xcl.repository.UserRepository;
import org.springframework.stereotype.Repository;import java.util.Collection;
import java.util.HashMap;
import java.util.Map;@Repository
public class UserRepositoryImpl implements UserRepository { private static Map<Integer,User> map;
static {
map=new HashMap<>();
map.put(1,new User(1,"张三"));
map.put(2,new User(2,"李四"));
map.put(3,new User(3,"王五"));
map.put(4,new User(4,"小张")); }
@Override
public Collection<User> findAll() {
return map.values();
} @Override
public User findById(Integer id) {
return map.get(id);
} @Override
public void saveOrUpdate(User user) {
map.put(user.getId(),user);
} @Override
public void deleteById(Integer id) {
map.remove(id);
}
}
Springmvc.xml 配置
<?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: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.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd">
<!-- ⾃动扫描 -->
<context:component-scan base-package="com.xcl"></context:component-scan> <!-- 视图解析器 -->
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<!-- 前缀 -->
<property name="prefix" value="/"></property>
<!-- 后缀 -->
<property name="suffix" value=".jsp"></property>
</bean>
<!-- JSON 使用-->
<mvc:annotation-driven>
<!-- 消息转换器 -->
<mvc:message-converters>
<bean class="com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter">
</bean>
</mvc:message-converters>
</mvc:annotation-driven></beans>
pom.xml 配置
<?xml version="1.0" encoding="UTF-8"?><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.xcl</groupId>
<artifactId>springmvc</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>war</packaging> <name>springmvc Maven Webapp</name>
<!-- FIXME change it to the project's website -->
<url>http://www.example.com</url> <properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>12</maven.compiler.source>
<maven.compiler.target>12</maven.compiler.target>
</properties> <dependencies> <dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency> <dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>5.1.7.RELEASE</version>
</dependency> <dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.0.1</version>
</dependency> <dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.10</version>
<scope>provided</scope>
</dependency> <!-- https://mvnrepository.com/artifact/com.alibaba/fastjson -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.62</version>
</dependency> </dependencies> <build>
<finalName>springmvc</finalName>
<pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
<plugins>
<plugin>
<artifactId>maven-clean-plugin</artifactId>
<version>3.1.0</version>
</plugin>
<!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
<plugin>
<artifactId>maven-resources-plugin</artifactId>
<version>3.0.2</version>
</plugin>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.0</version>
</plugin>
<plugin>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.22.1</version>
</plugin>
<plugin>
<artifactId>maven-war-plugin</artifactId>
<version>3.2.2</version>
</plugin>
<plugin>
<artifactId>maven-install-plugin</artifactId>
<version>2.5.2</version>
</plugin>
<plugin>
<artifactId>maven-deploy-plugin</artifactId>
<version>2.8.2</version>
</plugin>
</plugins>
</pluginManagement>
</build>
</project>
web.xml 配置
<!DOCTYPE web-app PUBLIC
"-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"http://java.sun.com/dtd/web-app_2_3.dtd" ><web-app>
<display-name>Archetype Created Web Application</display-name>
<servlet>
<servlet-name>springmvc</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:springmvc.xml</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>springmvc</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>
