Spring Cookies 教程|极客教程

Spring Cookies 教程展示了如何在 Spring 应用中使用 Cookie。使用@CookieValue 注解读取 Cookie。

Spring 是用于创建企业应用的流行 Java 应用框架。

Cookies

Cookie 是服务器发送到用户的 Web 浏览器的一小段数据。浏览器可以存储它，并将其与下一个请求一起发送回同一服务器。

Cookies 主要用于会话管理，个性化和跟踪。

`@CookieValue`

@CookieValue是一个注释，指示方法参数应绑定到 HTTP cookie。

`HttpCookie`

HttpCookie将 HTTP cookie 表示为与“ Cookie”请求标头的内容一致的名称/值对。 ResponseCookie子类具有“ Set-Cookie”响应标题中预期的其他属性。

Spring Cookie 的例子

以下示例创建一个写入和读取 Cookie 的 Spring Web 应用。

pom.xml
src
├───main
│   ├───java
│   │   └───com
│   │       └───zetcode
│   │           ├───config
│   │           │       MyWebInitializer.java
│   │           │       WebConfig.java
│   │           └───controller
│   │                   MyController.java
│   └───resources
│           logback.xml
└───test
    └───java

这是 Spring 应用的项目结构。

pom.xml

<?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.zetcode</groupId>
    <artifactId>cookiesex</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>11</maven.compiler.source>
        <maven.compiler.target>11</maven.compiler.target>
        <spring-version>5.1.3.RELEASE</spring-version>
    </properties>

    <dependencies>

        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>1.2.3</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>4.0.1</version>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.1.3.RELEASE</version>
        </dependency>

    </dependencies>

    <build>
        <plugins>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-war-plugin</artifactId>
                <version>3.2.2</version>
            </plugin>

            <plugin>
                <groupId>org.eclipse.jetty</groupId>
                <artifactId>jetty-maven-plugin</artifactId>
                <version>9.4.14.v20181114</version>
            </plugin>

        </plugins>
    </build>
</project>

我们声明项目依赖项。

resources/logback.xml

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <logger name="org.springframework" level="ERROR"/>
    <logger name="com.zetcode" level="INFO"/>

    <appender name="consoleAppender" class="ch.qos.logback.core.ConsoleAppender">
        <encoder>
            <Pattern>%d{HH:mm:ss.SSS} %blue(%-5level) %magenta(%logger{36}) - %msg %n
            </Pattern>
        </encoder>
    </appender>

    <root>
        <level value="INFO" />
        <appender-ref ref="consoleAppender" />
    </root>
</configuration>

logback.xml是 Logback 日志库的配置文件。

com/zetcode/config/MyWebInitializer.java

package com.zetcode.config;

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

@Configuration
public class MyWebInitializer extends
        AbstractAnnotationConfigDispatcherServletInitializer {

    @Override
    protected Class<?>[] getRootConfigClasses() {
        return null;
    }

    @Override
    protected Class<?>[] getServletConfigClasses() {

        return new Class[]{WebConfig.class};
    }

    @Override
    protected String[] getServletMappings() {

        return new String[]{"/"};
    }
}

DispatcherServlet是 Spring Web 应用的前端控制器，已注册在MyWebInitializer中。

@Override
protected Class<?>[] getServletConfigClasses() {

    return new Class[]{WebConfig.class};
}

getServletConfigClasses()返回 Web 配置类。

com/zetcode/config/WebConfig.java

package com.zetcode.config;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;

@Configuration
@EnableWebMvc
@ComponentScan(basePackages = {"com.zetcode"})
public class WebConfig {

}

WebConfig通过@EnableWebMvc启用 Spring MVC 注解，并为com.zetcode软件包配置组件扫描。

com/zetcode/MyController.java

package com.zetcode.controller;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseCookie;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.CookieValue;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.ResponseStatus;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class MyController {

    private static final Logger logger = LoggerFactory.getLogger(MyController.class);

    @ResponseStatus(value = HttpStatus.OK)
    @GetMapping(value = "/readCookie")
    public void readCookie(@CookieValue(value = "fav-col",
            defaultValue = "unknown") String favColour) {

        logger.info("Favourite colour: {}", favColour);
    }

    @ResponseStatus(value = HttpStatus.OK)
    @GetMapping(value = "/writeCookie")
    public ResponseEntity writeCookie() {

        var favColour = "steelblue";
        var cookie = ResponseCookie.from("fav-col", favColour).build();

        return ResponseEntity.ok()
                .header(HttpHeaders.SET_COOKIE, cookie.toString())
                .build();
    }
}

我们有两个 GET 映射。第一个映射读取一个 cookie，第二个映射写入一个 cookie。

public void readCookie(@CookieValue(value = "fav-col",
        defaultValue = "unknown") String favColour) {

我们使用@CookieValue读取 Cookie 值。如果未设置 cookie 或过期，则为默认值。

var favColour = "steelblue";
var cookie = ResponseCookie.from("fav-col", favColour).build();

return ResponseEntity.ok()
        .header(HttpHeaders.SET_COOKIE, cookie.toString())
        .build();