一、前言

上一篇《Spring Boot 入门之基础篇(一)》介绍了 Spring Boot 的环境搭建以及项目启动打包等基础内容,本篇继续深入介绍 Spring Boot 与 Web 开发相关的知识。

二、整合模板引擎

由于 jsp 不被 SpringBoot 推荐使用,所以模板引擎主要介绍 Freemarker 和 Thymeleaf。

2.1 整合 Freemarker

2.1.1 添加 Freemarker 依赖

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<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-freemarker</artifactId>
</dependency>

2.1.2 添加 Freemarker 模板配置

在 application.properties 中添加如下内容:

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spring.freemarker.allow-request-override=false
spring.freemarker.cache=true
spring.freemarker.check-template-location=true
spring.freemarker.charset=UTF-8
spring.freemarker.content-type=text/html
spring.freemarker.expose-request-attributes=false
spring.freemarker.expose-session-attributes=false
spring.freemarker.expose-spring-macro-helpers=false
spring.freemarker.prefix=
spring.freemarker.suffix=.ftl

上述配置都是默认值。

2.1.3 Freemarker 案例演示

在 controller 包中创建 FreemarkerController:

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@Controller
@RequestMapping("freemarker")
public class FreemarkerController {

@RequestMapping("hello")
public String hello(Map<String,Object> map) {

map.put("msg", "Hello Freemarker");
return "hello";
}
}

在 templates 目录中创建名为 hello.ftl 文件,内容如下:

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<!DOCTYPE html>
<html lang="zh">
<head>
<meta charset="UTF-8">
<title>Document</title>
<link href="/css/index.css" rel="stylesheet"/>
</head>
<body>
<div class="container">
<h2>${msg}</h2>
</div>
</body>
</html>

结果如下:

2.2 整合 Thymeleaf

2.2.1 添加 Thymeleaf 依赖

在 pom.xml 文件中添加:

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<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>

2.2.2 添加 Thymeleaf 模板配置

在 application.properties 中添加如下内容:

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spring.thymeleaf.cache=true
spring.thymeleaf.prefix=classpath:/templates/
spring.thymeleaf.suffix=.html
spring.thymeleaf.mode=HTML5
spring.thymeleaf.encoding=UTF-8
spring.thymeleaf.content-type=text/html

上述配置都是默认值。

2.2.3 Thymeleaf 案例演示

在 controller 包中创建 ThymeleafController:

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@Controller
@RequestMapping("thymeleaf")
public class ThymeleafController {

@RequestMapping("hello")
public String hello(Map<String,Object> map) {
map.put("msg", "Hello Thymeleaf");
return "hello";
}
}

在 template 目录下创建名为 hello.html 的文件,内容如下:

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<!DOCTYPE html>
<html lang="zh">
<head>
<meta charset="UTF-8">
<title>Document</title>
<link href="/css/index.css" rel="stylesheet"/>
</head>
<body>
<div class="container">
<h2 th:text="${msg}"></h2>
</div>
</body>
</html>

结果如下:

三、整合 Fastjson

3.1 添加依赖

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<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.35</version>
</dependency>

3.2 整合 Fastjson

创建一个配置管理类 WebConfig ,如下:

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@Configuration
public class WebConfig {

@Bean
public HttpMessageConverters fastJsonHttpMessageConverters() {
FastJsonHttpMessageConverter fastJsonHttpMessageConverter = new FastJsonHttpMessageConverter();

FastJsonConfig fastJsonConfig = new FastJsonConfig();
fastJsonConfig.setSerializerFeatures(SerializerFeature.PrettyFormat);

fastJsonHttpMessageConverter.setFastJsonConfig(fastJsonConfig);

HttpMessageConverter<?> converter = fastJsonHttpMessageConverter;

return new HttpMessageConverters(converter);

}
}

3.3 演示案例:

创建一个实体类 User:

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public class User {

private Integer id;

private String username;

private String password;

private Date birthday;

}

getter 和 setter 此处省略。

创建控制器类 FastjsonController :

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@Controller
@RequestMapping("fastjson")
public class FastJsonController {

@RequestMapping("/test")
@ResponseBody
public User test() {
User user = new User();

user.setId(1);
user.setUsername("jack");
user.setPassword("jack123");
user.setBirthday(new Date());

return user;
}
}

打开浏览器,访问 http://localhost:8080/fastjson/test,结果如下图:

此时,还不能看出 Fastjson 是否正常工作,我们在 User 类中使用 Fastjson 的注解,如下内容:

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@JSONField(format="yyyy-MM-dd")
private Date birthday;

再次访问 http://localhost:8080/fastjson/test,结果如下图:

日期格式与我们修改的内容格式一致,说明 Fastjson 整合成功。

四、自定义 Servlet

4.1 编写 Servlet

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public class ServletTest extends HttpServlet {

@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doPost(req, resp);
}

@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
resp.setContentType("text/html;charset=utf-8");
resp.getWriter().write("自定义 Servlet");
}

}

4.2 注册 Servlet

将 Servelt 注册成 Bean。在上文创建的 WebConfig 类中添加如下代码:

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@Bean
public ServletRegistrationBean servletRegistrationBean() {
return new ServletRegistrationBean(new ServletTest(),"/servletTest");
}

结果如下:

五、自定义过滤器/第三方过滤器

5.1 编写过滤器

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public class TimeFilter implements Filter {

@Override
public void init(FilterConfig filterConfig) throws ServletException {
System.out.println("=======初始化过滤器=========");
}

@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain)
throws IOException, ServletException {

long start = System.currentTimeMillis();

filterChain.doFilter(request, response);

System.out.println("filter 耗时:" + (System.currentTimeMillis() - start));

}

@Override
public void destroy() {
System.out.println("=======销毁过滤器=========");
}

}

5.2 注册过滤器

要是该过滤器生效,有两种方式:

  1. 使用 @Component 注解

  2. 添加到过滤器链中,此方式适用于使用第三方的过滤器。将过滤器写到 WebConfig 类中,如下:

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@Bean
public FilterRegistrationBean timeFilter() {
FilterRegistrationBean registrationBean = new FilterRegistrationBean();

TimeFilter timeFilter = new TimeFilter();
registrationBean.setFilter(timeFilter);

List<String> urls = new ArrayList<>();
urls.add("/*");
registrationBean.setUrlPatterns(urls);

return registrationBean;
}

结果如下:

六、自定义监听器

6.1 编写监听器

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public class ListenerTest implements ServletContextListener {

@Override
public void contextInitialized(ServletContextEvent sce) {
System.out.println("监听器初始化...");
}

@Override
public void contextDestroyed(ServletContextEvent sce) {

}

}

6.2 注册监听器

注册监听器为 Bean,在 WebConfig 配置类中添加如下代码:

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@Bean
public ServletListenerRegistrationBean<ListenerTest> servletListenerRegistrationBean() {
return new ServletListenerRegistrationBean<ListenerTest>(new ListenerTest());
}

当启动容器时,结果如下:

针对自定义 Servlet、Filter 和 Listener 的配置,还有另一种方式:

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@SpringBootApplication
public class SpringbootWebApplication implements ServletContextInitializer {

@Override
public void onStartup(ServletContext servletContext) throws ServletException {
// 配置 Servlet
servletContext.addServlet("servletTest",new ServletTest())
.addMapping("/servletTest");
// 配置过滤器
servletContext.addFilter("timeFilter",new TimeFilter())
.addMappingForUrlPatterns(EnumSet.of(DispatcherType.REQUEST),true,"/*");
// 配置监听器
servletContext.addListener(new ListenerTest());
}

public static void main(String[] args) {
SpringApplication.run(SpringbootWebApplication.class, args);
}
}

七、自定义拦截器

7.1 编写拦截器

使用 @Component 让 Spring 管理其生命周期:

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@Component
public class TimeInterceptor implements HandlerInterceptor {

@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {

System.out.println("========preHandle=========");
System.out.println(((HandlerMethod)handler).getBean().getClass().getName());
System.out.println(((HandlerMethod)handler).getMethod().getName());

request.setAttribute("startTime", System.currentTimeMillis());

return true;
}

@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView)
throws Exception {

System.out.println("========postHandle=========");
Long start = (Long) request.getAttribute("startTime");
System.out.println("耗时:"+(System.currentTimeMillis() - start));
}

@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception exception)
throws Exception {

System.out.println("========afterCompletion=========");
Long start = (Long) request.getAttribute("startTime");
System.out.println("耗时:"+(System.currentTimeMillis() - start));

System.out.println(exception);
}

}

7.2 注册拦截器

编写拦截器后,我们还需要将其注册到拦截器链中,如下配置:

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@Configuration
public class WebConfig extends WebMvcConfigurerAdapter{

@Autowired
private TimeInterceptor timeInterceptor;


@Override
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(timeInterceptor);
}

}

请求一个 controller ,结果如下:

八、配置 AOP 切面

8.1 添加依赖

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<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-aop</artifactId>
</dependency>

8.2 编写切面类

使用 @Component,@Aspect 标记到切面类上:

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@Aspect
@Component
public class TimeAspect {

@Around("execution(* com.light.springboot.controller.FastJsonController..*(..))")
public Object method(ProceedingJoinPoint pjp) throws Throwable {

System.out.println("=====Aspect处理=======");
Object[] args = pjp.getArgs();
for (Object arg : args) {
System.out.println("参数为:" + arg);
}

long start = System.currentTimeMillis();

Object object = pjp.proceed();

System.out.println("Aspect 耗时:" + (System.currentTimeMillis() - start));

return object;
}
}

请求 FastJsonController 控制器的方法,结果如下:

九、错误处理

9.1 友好页面

先演示非友好页面,修改 FastJsonController 类中的 test 方法:

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@RestController
@RequestMapping("fastjson")
public class FastJsonController {

@RequestMapping("/test")
public User test() {
User user = new User();

user.setId(1);
user.setUsername("jack");
user.setPassword("jack123");
user.setBirthday(new Date());

// 模拟异常
int i = 1/0;

return user;
}
}

浏览器请求:http://localhost:8080/fastjson/test,结果如下:

当系统报错时,返回到页面的内容通常是一些杂乱的代码段,这种显示对用户来说不友好,因此我们需要自定义一个友好的提示系统异常的页面。

在 src/main/resources 下创建 /public/error,在该目录下再创建一个名为 5xx.html 文件,该页面的内容就是当系统报错时返回给用户浏览的内容:

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<!DOCTYPE html>
<html lang="zh">
<head>
<meta charset="UTF-8">
<title>系统错误</title>
<link href="/css/index.css" rel="stylesheet"/>
</head>
<body>
<div class="container">
<h2>系统内部错误</h2>
</div>
</body>
</html>

路径时固定的,Spring Boot 会在系统报错时将返回视图指向该目录下的文件。

如下图:

上边处理的 5xx 状态码的问题,接下来解决 404 状态码的问题。

当出现 404 的情况时,用户浏览的页面也不够友好,因此我们也需要自定义一个友好的页面给用户展示。

在 /public/error 目录下再创建一个名为 404.html 的文件:

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<!DOCTYPE html>
<html lang="zh">
<head>
<meta charset="UTF-8">
<title>访问异常</title>
<link href="/css/index.css" rel="stylesheet"/>
</head>
<body>
<div class="container">
<h2>找不到页面</h2>
</div>
</body>
</html>

我们请求一个不存在的资源,如:http://localhost:8080/fastjson/test2,结果如下图:

9.2 全局异常捕获

如果项目前后端是通过 JSON 进行数据通信,则当出现异常时可以常用如下方式处理异常信息。

编写一个类充当全局异常的处理类,需要使用 @ControllerAdvice 和 @ExceptionHandler 注解:

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@ControllerAdvice
public class GlobalDefaultExceptionHandler {

/**
* 处理 Exception 类型的异常
* @param e
* @return
*/
@ExceptionHandler(Exception.class)
@ResponseBody
public Map<String,Object> defaultExceptionHandler(Exception e) {

Map<String,Object> map = new HashMap<String,Object>();
map.put("code", 500);
map.put("msg", e.getMessage());
return map;
}
}

其中,方法名为任意名,入参一般使用 Exception 异常类,方法返回值可自定义。

启动项目,访问 http://localhost:8080/fastjson/test,结果如下图:

我们还可以自定义异常,在全局异常的处理类中捕获和判断,从而对不同的异常做出不同的处理。

十、文件上传和下载

10.1 添加依赖

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<!-- 工具 -->
<dependency>
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>2.4</version>
</dependency>

10.2 实现

编写一个实体类,用于封装返回信息:

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public class FileInfo {

private String path;

public FileInfo(String path) {
this.path = path;
}

public String getPath() {
return path;
}

public void setPath(String path) {
this.path = path;
}

}

编写 Controller,用于处理文件上传下载:

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@RestController
@RequestMapping("/file")
public class FileController {

private String path = "d:\\";

@PostMapping
public FileInfo upload(MultipartFile file) throws Exception {

System.out.println(file.getName());
System.out.println(file.getOriginalFilename());
System.out.println(file.getSize());

File localFile = new File(path, file.getOriginalFilename());

file.transferTo(localFile);

return new FileInfo(localFile.getAbsolutePath());
}

@GetMapping("/{id}")
public void download(@PathVariable String id, HttpServletRequest request, HttpServletResponse response) {
try (InputStream inputStream = new FileInputStream(new File(path, id + ".jpg"));
OutputStream outputStream = response.getOutputStream();) {

response.setContentType("application/x-download");
response.addHeader("Content-Disposition", "attachment;filename=" + id + ".jpg");

IOUtils.copy(inputStream, outputStream);
} catch (Exception e) {
e.printStackTrace();
}
}
}

基本上都是在学习 javaweb 时用到的 API。

文件上传测试结果如下图:

十一、CORS 支持

前端页面:

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<!DOCTYPE html>
<html lang="en">

<head>
<meta charset="UTF-8">
<title>跨域测试</title>
</head>

<body>
<button id="test">测试</button>
<script type="text/javascript" src="jquery-1.12.3.min.js"></script>
<script type="text/javascript">
$(function() {
$("#test").on("click", function() {
$.ajax({
"url": "http://localhost:8080/fastjson/test",
"type": "get",
"dataType": "json",
"success": function(data) {
console.log(data);
}
})
});
});
</script>
</body>

</html>

通过 http 容器启动前端页面代码,笔者使用 Sublime Text 的插件启动的,测试结果如下:

从图中可知,前端服务器启动端口为 8088 与后端服务器 8080 不同源,因此出现跨域的问题。

现在开始解决跨域问题,可以两种维度控制客户端请求。

粗粒度控制

方式一

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@Configuration
public class WebConfig {

@Bean
public WebMvcConfigurer corsConfigurer() {
return new WebMvcConfigurerAdapter() {
@Override
public void addCorsMappings(CorsRegistry registry) {
registry.addMapping("/fastjson/**")
.allowedOrigins("http://localhost:8088");// 允许 8088 端口访问
}
};
}
}

方式二

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@Configuration
public class WebConfig extends WebMvcConfigurerAdapter{

@Override
public void addCorsMappings(CorsRegistry registry) {
registry.addMapping("/fastjson/**")
.allowedOrigins("http://localhost:8088");// 允许 8088 端口访问
}
}

配置后,重新发送请求,结果如下:

细粒度控制

在 FastJsonController 类中的方法上添加 @CrossOrigin(origins="xx") 注解:

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@RequestMapping("/test")
@CrossOrigin(origins="http://localhost:8088")
public User test() {
User user = new User();

user.setId(1);
user.setUsername("jack");
user.setPassword("jack123");
user.setBirthday(new Date());

return user;
}

在使用该注解时,需要注意 @RequestMapping 使用的请求方式类型,即 GET 或 POST。

十二、整合 WebSocket

12.1 添加依赖

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<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-websocket</artifactId>
</dependency>

12.2 实现方式

方式一:

该方式只适用于通过 jar 包直接运行项目的情况。

WebSocket 配置类:

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@Configuration
public class WebSocketConfig {

@Bean
public ServerEndpointExporter serverEndpointExporter() {
return new ServerEndpointExporter();
}

}

WebSocket 处理类:

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@ServerEndpoint(value = "/webSocketServer/{userName}")
@Component
public class WebSocketServer {

private static final Set<WebSocketServer> connections = new CopyOnWriteArraySet<>();

private String nickname;
private Session session;

private static String getDatetime(Date date) {
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
return format.format(date);
}

@OnOpen
public void start(@PathParam("userName") String userName, Session session) {
this.nickname = userName;
this.session = session;
connections.add(this);
String message = String.format("* %s %s", nickname, "加入聊天!");
broadcast(message);
}

@OnClose
public void end() {
connections.remove(this);
String message = String.format("* %s %s", nickname, "退出聊天!");
broadcast(message);
}

@OnMessage
public void pushMsg(String message) {
broadcast("【" + this.nickname + "】" + getDatetime(new Date()) + " : " + message);
}

@OnError
public void onError(Throwable t) throws Throwable {

}

private static void broadcast(String msg) {
// 广播形式发送消息
for (WebSocketServer client : connections) {
try {
synchronized (client) {
client.session.getBasicRemote().sendText(msg);
}
} catch (IOException e) {
connections.remove(client);
try {
client.session.close();
} catch (IOException e1) {
e.printStackTrace();
}
String message = String.format("* %s %s", client.nickname, "断开连接");
broadcast(message);
}
}
}
}

前端页面:

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<!DOCTYPE html>
<html>

<head lang="zh">
<meta charset="UTF-8">
<link rel="stylesheet" href="css/bootstrap.min.css">
<link rel="stylesheet" href="css/bootstrap-theme.min.css">
<script src="js/jquery-1.12.3.min.js"></script>
<script src="js/bootstrap.js"></script>
<style type="text/css">
#msg {
height: 400px;
overflow-y: auto;
}

#userName {
width: 200px;
}

#logout {
display: none;
}
</style>
<title>webSocket测试</title>
</head>

<body>
<div class="container">
<div class="page-header" id="tou">webSocket及时聊天Demo程序</div>
<p class="text-right" id="logout">
<button class="btn btn-danger" id="logout-btn">退出</button>
</p>
<div class="well" id="msg"></div>
<div class="col-lg">
<div class="input-group">
<input type="text" class="form-control" placeholder="发送信息..." id="message"> <span class="input-group-btn">
<button class="btn btn-default" type="button" id="send"
disabled="disabled">发送</button>
</span>
</div>
<div class="input-group">
<input id="userName" type="text" class="form-control" name="userName" placeholder="输入您的用户名" />
<button class="btn btn-default" type="button" id="connection-btn">建立连接</button>
</div>
<!-- /input-group -->
</div>
<!-- /.col-lg-6 -->
</div>
<!-- /.row -->
</div>
<script type="text/javascript">
$(function() {
var websocket;
$("#connection-btn").bind("click", function() {
var userName = $("#userName").val();
if (userName == null || userName == "") {
alert("请输入您的用户名");
return;
}
connection(userName);
});

function connection(userName) {
var host = window.location.host;
if ('WebSocket' in window) {
websocket = new WebSocket("ws://" + host +
"/webSocketServer/" + userName);
} else if ('MozWebSocket' in window) {
websocket = new MozWebSocket("ws://" + host +
"/webSocketServer/" + userName);
}
websocket.onopen = function(evnt) {
$("#tou").html("链接服务器成功!")
$("#send").prop("disabled", "");
$("#connection-btn").prop("disabled", "disabled");
$("#logout").show();
};
websocket.onmessage = function(evnt) {
$("#msg").html($("#msg").html() + "<br/>" + evnt.data);
};
websocket.onerror = function(evnt) {
$("#tou").html("报错!")
};
websocket.onclose = function(evnt) {
$("#tou").html("与服务器断开了链接!");
$("#send").prop("disabled", "disabled");
$("#connection-btn").prop("disabled", "");
$("#logout").hide();
}
}

function send() {
if (websocket != null) {
var $message = $("#message");
var data = $message.val();
if (data == null || data == "") {
return;
}
websocket.send(data);
$message.val("");
} else {
alert('未与服务器链接.');
}
}

$('#send').bind('click', function() {
send();
});

$(document).on("keypress", function(event) {
if (event.keyCode == "13") {
send();
}
});

$("#logout-btn").on("click", function() {
websocket.close(); //关闭TCP连接
});
});
</script>
</body>

</html>

演示图如下:

如果使用该方式实现 WebSocket 功能并打包成 war 运行会报错:

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javax.websocket.DeploymentException: Multiple Endpoints may not be deployed to the same path 

方式二:

该方式适用于 jar 包方式运行和 war 方式运行。

WebSocket 配置类:

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@Configuration  
@EnableWebSocket
public class WebSocketConfig implements WebSocketConfigurer {
@Override
public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
registry.addHandler(webSocketServer(), "/webSocketServer/*");
}

@Bean
public WebSocketHandler webSocketServer() {
return new WebSocketServer();
}
}

WebSocket 处理类:

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public class WebSocketServer extends TextWebSocketHandler {

private static final Map<WebSocketSession, String> connections = new ConcurrentHashMap<>();

private static String getDatetime(Date date) {
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
return format.format(date);
}

/**
* 建立连接
*/
@Override
public void afterConnectionEstablished(WebSocketSession session) throws Exception {

String uri = session.getUri().toString();
String userName = uri.substring(uri.lastIndexOf("/") + 1);

String nickname = URLDecoder.decode(userName, "utf-8");

connections.put(session, nickname);
String message = String.format("* %s %s", nickname, "加入聊天!");

broadcast(new TextMessage(message));
}

/**
* 断开连接
*/
@Override
public void afterConnectionClosed(WebSocketSession session, CloseStatus status) throws Exception {
String nickname = connections.remove(session);
String message = String.format("* %s %s", nickname, "退出聊天!");

broadcast(new TextMessage(message));
}

/**
* 处理消息
*/
@Override
protected void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception {
String msg = "【" + connections.get(session) + "】" + getDatetime(new Date()) + " : " + message.getPayload();

broadcast(new TextMessage(msg));
}

private static void broadcast(TextMessage msg) {
// 广播形式发送消息
for (WebSocketSession session : connections.keySet()) {
try {
synchronized (session) {
session.sendMessage(msg);
}
} catch (Exception e) {
connections.remove(session);
try {
session.close();
} catch (Exception e2) {
e2.printStackTrace();
}
String message = String.format("* %s %s", connections.get(session), "断开连接");
broadcast(new TextMessage(message));
}
}
}
}

运行结果与上图一致。

十三、整合 JavaMail

本次测试演示带模板的邮件,使用 Freemark 实现邮件的模板。

13.1 添加依赖

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<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-mail</artifactId>
</dependency>

<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-freemarker</artifactId>
</dependency>

13.2 添加配置

在 application.properties 中添加

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# javamail 配置
spring.mail.host=smtp.163.com
spring.mail.username=13738137546@163.com
spring.mail.password=
spring.mail.properties.mail.smtp.auth=true
spring.mail.properties.mail.smtp.starttls.enable=true
spring.mail.properties.mail.smtp.starttls.required=true

13.3 编码

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@Component
@EnableConfigurationProperties(MailProperties.class)
public class JavaMailComponent {

private static final String template = "mail.ftl";

@Autowired
private FreeMarkerConfigurer freeMarkerConfigurer;

@Autowired
private JavaMailSender javaMailSender;

@Autowired
private MailProperties mailProperties;

public void sendMail(String email) {
Map<String, Object> map = new HashMap<String, Object>();
map.put("email", email);
try {
// 获取内容
String text = this.getTextByTemplate(template, map);
// 发送
this.send(email, text);
} catch (Exception e) {
e.printStackTrace();
}
}

private String getTextByTemplate(String template, Map<String, Object> model) throws Exception {
return FreeMarkerTemplateUtils
.processTemplateIntoString(this.freeMarkerConfigurer.getConfiguration().getTemplate(template), model);
}

private String send(String email, String text) throws MessagingException, UnsupportedEncodingException {
MimeMessage message = this.javaMailSender.createMimeMessage();
MimeMessageHelper helper = new MimeMessageHelper(message, true, "UTF-8");
InternetAddress from = new InternetAddress();
from.setAddress(this.mailProperties.getUsername());
from.setPersonal("月光中的污点", "UTF-8");
helper.setFrom(from);
helper.setTo(email);
helper.setSubject("SpringBoot 发送的第一封邮件");
helper.setText(text, true);
this.javaMailSender.send(message);
return text;
}
}

在 src/main/resources 下的 template 目录下创建名为 mail.ftl 的文件,其内容如下:

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<!DOCTYPE html>
<html lang="zh">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
</head>
<body>
<div style="width: 600px; text-align: left; margin: 0 auto;">
<h1 style="color: #005da7;">月光中的污点</h1>
<div style="border-bottom: 5px solid #005da7; height: 2px; width: 100%;"></div>
<div style="border: 1px solid #005da7; font-size: 16px; line-height: 50px; padding: 20px;">
<div>${email},您好!</div>
<div>
这是个测试
</div>
<div>
想了解更多信息,请访问 <a href="https://www.extlight.com">https://www.extlight.com</a>
</div>
</div>
</div>
</body>
</html>

13.4 测试

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@RunWith(SpringRunner.class)
@SpringBootTest
public class MailTest {

@Autowired
private JavaMailComponent javaMailComponent;

@Test
public void test() {
this.javaMailComponent.sendMail("445847261@qq.com");
}
}

运行结果如下图:

十四、整合定时任务

定时器的实现有 2 种方式:

1) Scheduled:spring 3.0 后自带的定时器

2)Quartz:第三放定时器框架

14.1 Scheduled 方式

14.1.1 任务类

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@Component
public class Schedule {

@Scheduled(fixedRate = 2000)
public void task() {
System.out.println("启动定时任务:" + new Date());
}
}

使用 @Scheduled 定义任务执行时间,代码中表示每隔 2 秒执行一次任务。

14.1.2 开启定时计划

只需在 Spring Boot 的启动类上添加 @EnableScheduling 后,启动项目即可。

测试结果如下图:

14.2 Quartz 方式

14.2.1 任务类

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public class MyJob implements Job {
@Override
public void execute(JobExecutionContext jobExecutionContext) throws JobExecutionException {
System.out.println("========quartz 测试==========");
}
}

14.2.2 配置类

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@Configuration
public class QuartzConfiguration {

/**
* Job 工厂
* @return
*/
@Bean
public JobDetailFactoryBean jobDetailFactoryBean() {
JobDetailFactoryBean factory = new JobDetailFactoryBean();
factory.setJobClass(MyJob.class);
return factory;
}

/**
* Trigger 工厂
* @return
*/
@Bean
public SimpleTriggerFactoryBean simpleTriggerFactoryBean(JobDetailFactoryBean jobDetailFactory) {
SimpleTriggerFactoryBean factory = new SimpleTriggerFactoryBean();
factory.setJobDetail(jobDetailFactory.getObject());
// 执行间隔时间
factory.setRepeatInterval(5000);
// 重复执行次数
factory.setRepeatCount(3);
return factory;
}

/**
* Trigger 工厂
* @return
*/
@Bean
public CronTriggerFactoryBean cronTriggerFactoryBean(JobDetailFactoryBean jobDetailFactory) {
CronTriggerFactoryBean factory = new CronTriggerFactoryBean();
factory.setJobDetail(jobDetailFactory.getObject());
factory.setCronExpression("0/5 * * * * ?");
return factory;
}

/* @Bean
public SchedulerFactoryBean schedulerFactoryBean(SimpleTriggerFactoryBean simpleTriggerFactory){
SchedulerFactoryBean factory = new SchedulerFactoryBean();
factory.setTriggers(simpleTriggerFactory.getObject());
return factory;
}*/

@Bean
public SchedulerFactoryBean schedulerFactoryBean(CronTriggerFactoryBean cronTriggerFactory){
SchedulerFactoryBean factory = new SchedulerFactoryBean();
factory.setTriggers(cronTriggerFactory.getObject());
return factory;
}
}

同样地,需要在 Spring Boot 的启动类上添加 @EnableScheduling 后,启动项目即可。

14.2.3 依赖注入问题

实际开发中,任务类需要注入业务组件来执行定时任务,如下:

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public class MyJob implements Job {

@Autowired
private UserService userService;

@Override
public void execute(JobExecutionContext jobExecutionContext) throws JobExecutionException {
this.userService.save();
}
}

但是,MyJob 生命周期并没有被 Spring 容器管理,因此无法注入 UserService,当定时器执行任务时会报空指针异常。

解决方案:

自定义任务工厂,重写创建任务实例的方法:

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@Component("customAdaptableJobFactory")
public class CustomAdaptableJobFactory extends AdaptableJobFactory {

@Autowired
private AutowireCapableBeanFactory autowireCapableBeanFactory;

@Override
protected Object createJobInstance(TriggerFiredBundle bundle) throws Exception {
Object object = super.createJobInstance(bundle);
// 将任务实例纳入 Spring 容器中
this.autowireCapableBeanFactory.autowireBean(object);
return object;
}
}

修改 Scheduler 实现:

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@Bean
public SchedulerFactoryBean schedulerFactoryBean(CronTriggerFactoryBean cronTriggerFactory,CustomAdaptableJobFactory customAdaptableJobFactory){
SchedulerFactoryBean factory = new SchedulerFactoryBean();
factory.setTriggers(cronTriggerFactory.getObject());
factory.setJobFactory(customAdaptableJobFactory);
return factory;
}

十五、整合 Swagger2

15.1 添加依赖

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<dependency>
<groupId>io.springfox</groupId>
<artifactId>springfox-swagger2</artifactId>
<version>2.7.0</version>
</dependency>
<dependency>
<groupId>io.springfox</groupId>
<artifactId>springfox-swagger-ui</artifactId>
<version>2.7.0</version>
</dependency>

15.2 配置

重新创建一个配置类,如下:

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@Configuration
@EnableSwagger2
public class Swagger2Configuration {

@Bean
public Docket accessToken() {
return new Docket(DocumentationType.SWAGGER_2)
.groupName("api")// 定义组
.select() // 选择那些路径和 api 会生成 document
.apis(RequestHandlerSelectors.basePackage("com.light.springboot.controller")) // 拦截的包路径
.paths(PathSelectors.regex("/*/.*"))// 拦截的接口路径
.build() // 创建
.apiInfo(apiInfo()); // 配置说明
}

private ApiInfo apiInfo() {
return new ApiInfoBuilder()//
.title("Spring Boot 之 Web 篇")// 标题
.description("spring boot Web 相关内容")// 描述
.termsOfServiceUrl("http://www.extlight.com")//
.contact(new Contact("moonlightL", "http://www.extlight.com", "445847261@qq.com"))// 联系
.version("1.0")// 版本
.build();
}
}

为了能更好的说明接口信息,我们还可以在 Controller 类上使用 Swagger2 相关注解说明信息。

我们以 FastJsonController 为例:

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@Api(value = "FastJson测试", tags = { "测试接口" })
@RestController
@RequestMapping("fastjson")
public class FastJsonController {

@ApiOperation("获取用户信息")
@ApiImplicitParam(name = "name", value = "用户名", dataType = "string", paramType = "query")
@GetMapping("/test/{name}")
public User test(@PathVariable("name") String name) {
User user = new User();

user.setId(1);
user.setUsername(name);
user.setPassword("jack123");
user.setBirthday(new Date());

return user;
}
}

注意,上边的方法是用 @GetMapping 注解,如果只是使用 @RequestMapping 注解,不配置 method 属性,那么 API 文档会生成 7 种请求方式。

启动项目,打开浏览器访问 http://localhost:8080/swagger-ui.html。结果如下图: