@RequestMapping( value = {"/{user_name}/update"}, method = {RequestMethod.GET} ) public void update(@PathVariable String user_name, Model model, HttpServletRequest request, HttpServletResponse response) throws Exception { UserInfo userInfo = this.userInfoService.getUserInfo(user_name); response.setContentType("text/json;charset=UTF-8"); PrintWriter out = response.getWriter(); JSONObject jsonUserInfo = userInfo.getJsonObject(); out.println(jsonUserInfo.toString()); out.flush(); out.close(); }

这是一个使用Spring MVC框架的Java代码段，用于处理GET请求并返回用户信息的JSON对象。具体来说，它使用了@RequestMapping注释将URL映射到处理程序方法上，@PathVariable注释将URI模板变量映射到方法参数上，Model对象用于向视图层传递数据，HttpServletRequest和HttpServletResponse对象用于处理HTTP请求和响应，UserInfoService对象用于获取用户信息，JSONObject对象用于将用户信息转换为JSON格式，PrintWriter对象用于将JSON字符串写入HTTP响应中。

相关问题

springboot整合redis整合@Cacheable、@CachePut、@CacheEvict注解增删改查实例

好的，下面是一个使用Spring Boot整合Redis的`@Cacheable`、`@CachePut`、`@CacheEvict`注解实现增删改查的示例：

1. 添加Redis依赖

在pom.xml中添加以下依赖：

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-cache</artifactId>
</dependency>

2. 配置Redis连接

在application.properties中添加以下配置：

# Redis连接配置
spring.redis.host=localhost
spring.redis.port=6379
spring.redis.password=

# 开启缓存
spring.cache.type=redis

3. 编写Redis配置类

import org.springframework.cache.CacheManager;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.cache.interceptor.KeyGenerator;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.cache.RedisCacheManager;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.RedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;

import java.lang.reflect.Method;
import java.util.Arrays;

@Configuration
@EnableCaching
public class RedisConfig {

    @Bean
    public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory redisConnectionFactory) {
        RedisTemplate<String, Object> redisTemplate = new RedisTemplate<>();
        redisTemplate.setConnectionFactory(redisConnectionFactory);

        // key序列化方式
        RedisSerializer<String> stringRedisSerializer = new StringRedisSerializer();
        redisTemplate.setKeySerializer(stringRedisSerializer); // key
        redisTemplate.setHashKeySerializer(stringRedisSerializer); // hash key

        // value序列化方式
        RedisSerializer<Object> valueRedisSerializer = new GenericJackson2JsonRedisSerializer();
        redisTemplate.setValueSerializer(valueRedisSerializer); // value
        redisTemplate.setHashValueSerializer(valueRedisSerializer); // hash value

        redisTemplate.afterPropertiesSet();
        return redisTemplate;
    }

    @Bean
    public CacheManager cacheManager(RedisConnectionFactory redisConnectionFactory) {
        RedisCacheManager.RedisCacheManagerBuilder builder = RedisCacheManager.RedisCacheManagerBuilder.fromConnectionFactory(redisConnectionFactory);
        return builder.build();
    }

    @Bean
    public KeyGenerator wiselyKeyGenerator() {
        return (Object target, Method method, Object... params) -> {
            StringBuilder sb = new StringBuilder();
            sb.append(target.getClass().getName());
            sb.append(method.getName());
            Arrays.stream(params).forEach(param -> sb.append(param.toString()));
            return sb.toString();
        };
    }
}

4. 编写实体类

import java.io.Serializable;

public class User implements Serializable {
    private static final long serialVersionUID = 1L;

    private Integer id;
    private String name;
    private Integer age;

    public User(Integer id, String name, Integer age) {
        this.id = id;
        this.name = name;
        this.age = age;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }
}

5. 编写Service

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.annotation.CacheEvict;
import org.springframework.cache.annotation.CachePut;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.stereotype.Service;

@Service
public class UserService {

    @Autowired
    private UserDao userDao;

    @Cacheable(value = "user", keyGenerator = "wiselyKeyGenerator")
    public User getUserById(Integer id) {
        return userDao.getUserById(id);
    }

    @CachePut(value = "user", keyGenerator = "wiselyKeyGenerator")
    public User updateUser(User user) {
        userDao.updateUser(user);
        return user;
    }

    @CacheEvict(value = "user", keyGenerator = "wiselyKeyGenerator")
    public void deleteUserById(Integer id) {
        userDao.deleteUserById(id);
    }
}

6. 编写Controller

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/user")
public class UserController {

    @Autowired
    private UserService userService;

    @GetMapping("/{id}")
    public User getUserById(@PathVariable Integer id) {
        return userService.getUserById(id);
    }

    @PutMapping("")
    public User updateUser(@RequestBody User user) {
        return userService.updateUser(user);
    }

    @DeleteMapping("/{id}")
    public void deleteUserById(@PathVariable Integer id) {
        userService.deleteUserById(id);
    }
}

7. 测试

启动应用后，可以通过以下方式测试：

- 获取用户：GET http://localhost:8080/user/1

- 更新用户：PUT http://localhost:8080/user

请求体：

  {
      "id": 1,
      "name": "Tom",
      "age": 20
  }

- 删除用户：DELETE http://localhost:8080/user/1

以上就是一个使用Spring Boot整合Redis的`@Cacheable`、`@CachePut`、`@CacheEvict`注解实现增删改查的示例。

解析接口：在应用启动时，Feign会扫描所有带有@FeignClient注解的接口，并将其解析成可执行的HTTP请求，生成动态代理对象并保存在Spring的ApplicationContext中。举个例子

比如我们有一个名为UserService的服务，它提供了一些RESTful API，我们想通过Feign来调用这些API。我们可以先定义一个接口，如下所示：

@FeignClient(name = "user-service")
public interface UserFeignClient {

    @RequestMapping(method = RequestMethod.GET, value = "/users/{userId}")
    User getUser(@PathVariable("userId") String userId);

    @RequestMapping(method = RequestMethod.POST, value = "/users")
    User createUser(@RequestBody User user);

    @RequestMapping(method = RequestMethod.PUT, value = "/users/{userId}")
    User updateUser(@PathVariable("userId") String userId, @RequestBody User user);

    @RequestMapping(method = RequestMethod.DELETE, value = "/users/{userId}")
    void deleteUser(@PathVariable("userId") String userId);

}

上述代码中，@FeignClient注解指定了服务名为"user-service"，Feign会根据这个服务名来发起HTTP请求。接口中的每个方法都对应一个HTTP请求，通过@RequestMapping注解指定请求的方法、路径、参数等信息。

接口定义好之后，我们就可以在代码中直接注入这个接口，并调用它的方法来发起HTTP请求，如下所示：

@RestController
public class UserController {

    @Autowired
    private UserFeignClient userFeignClient;

    @GetMapping("/users/{userId}")
    public User getUser(@PathVariable String userId) {
        return userFeignClient.getUser(userId);
    }

    @PostMapping("/users")
    public User createUser(@RequestBody User user) {
        return userFeignClient.createUser(user);
    }

    @PutMapping("/users/{userId}")
    public User updateUser(@PathVariable String userId, @RequestBody User user) {
        return userFeignClient.updateUser(userId, user);
    }

    @DeleteMapping("/users/{userId}")
    public void deleteUser(@PathVariable String userId) {
        userFeignClient.deleteUser(userId);
    }

}

上述代码中，我们注入了UserFeignClient接口，并在方法中直接调用它的方法来发起HTTP请求。Feign会自动将接口中定义的参数和返回值转换成对应的HTTP请求和响应。