Spring Boot（七）：web开发之模板引擎

介绍

目前开发大都前后端分离，这里学习模板引擎只做了解。模板引擎的选择可以有：FreeMarker、Thymeleaf、Groovy、Mustache等。增加的css、js、等文件的目录结构：

FreeMarker

pom引用

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

FreeMarkerController

@Controller
@RequestMapping(value = "/web")
public class FreeMarkerController {
    @RequestMapping(value = "index")
    public String index(ModelMap map) {//ModelMap选择可以有很多种，不做了解
        map.put("title", "freemarker hello world");
        return "index"; // 开头不要加上/，linux下面会出错
    }
}

index.ftl

<!DOCTYPE html>
<html>
    <head lang="en">
        <title>Spring Boot Demo - FreeMarker</title>
        <link href="/css/index.css" rel="stylesheet" />
    </head>
    <body>
        <center>
            <img src="/images/lele.jpg" />
            <h1 id="title">${title}</h1>
        </center>

       <script type="text/javascript" src="/webjars/jquery/2.1.4/jquery.min.js">		</script>
        <script>
            $(function(){
                $('#title').click(function(){
                alert('点击了');
                });
            })
        </script>
    </body>
</html>

thymeleaf

pom引用

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

index.html

<!DOCTYPE html>
<html>
    <head lang="en">
        <title>Spring Boot Demo - thymeleaf</title>
        <link href="/css/index.css" rel="stylesheet" />	
    </head>
    <body>
        <center>
            <img src="/images/lele.jpg" />
            <h1 id="title" th:text="${title}"></h1>
        </center>
    </body>
</html>

jsp

springboot不建议使用：

jsp只能打包为：war格式，不支持jar格式，只能在标准的容器里面跑（tomcat，jetty都可以）
内嵌的Jetty目前不支持JSPs
Undertow不支持jsps
jsp自定义错误页面不能覆盖spring boot 默认的错误页面

pom引用

<dependency>
	<groupId>org.apache.tomcat.embed</groupId>
	<artifactId>tomcat-embed-jasper</artifactId>
	<scope>provided</scope>
</dependency>
<dependency>
	<groupId>javax.servlet</groupId>
	<artifactId>jstl</artifactId>
</dependency>

application.properties

1 2	spring.mvc.view.prefix: /WEB-INF/templates/ spring.mvc.view.suffix: .jsp

index.jsp

<%@ taglib prefix="spring" uri="http://www.springframework.org/tags"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<!DOCTYPE html>
<html>
    <head lang="en">
        <title>Spring Boot Demo - FreeMarker</title>
        <link href="/static/css/index.css" rel="stylesheet" />
    </head>
    <body>
        <img src="/static/images/lele.jpg" alt="logo"/>
        <h1 id="title">${title}</h1>
        <c:url value="http://www.baidu.com" var="url"/>
      <spring:url value="http://www.baidu.com" htmlEscape="true" var="springUrl"/>
        Spring URL: ${springUrl}
        <br>
        JSTL URL: ${url}
    </body>
</html>

ServletInitializer.java

import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.web.support.SpringBootServletInitializer;
/**
 * 在Servlet容器中部署WAR的时候，不能依赖于Application的main函数而是要以类似于web.xml文件配置的方式来启动Spring应用上下文<br/>
 * 所以此时需要声明这样一个类或者将应用的主类改为继承SpringBootServletInitializer也可以
 */
public class ServletInitializer extends SpringBootServletInitializer {
	@Override
	protected SpringApplicationBuilder configure(SpringApplicationBuilder 																application) {
		return application.sources(SpringBootDemo81Application.class);
	}
}

错误处理

增加错误处理页面

ErrorController

BaseErrorController

@Controller
@RequestMapping(value = "error")
public class BaseErrorController implements ErrorController {
    private static final Logger logger = LoggerFactory.getLogger(BaseErrorController.class);
    @Override
    public String getErrorPath() {
        logger.info("出错啦！进入自定义错误控制器");
        return "error/error";
    }
    @RequestMapping
    public String error() {
        return getErrorPath();
    }
}

error.ftl

<!DOCTYPE html>
<html>
    <head lang="en">
        <title>Spring Boot Demo - error</title>
    </head>
    <body>
    	<h1>error-系统出错，请联系后台管理员</h1>
    </body>
</html>

自定义错误页面

html静态页面：在resources/public/error/ 下定义，如添加404页面： resources/public/error/404.html页面，中文注意页面编码
模板引擎页面：在templates/error/下定义，如添加5xx页面： templates/error/5xx.ftl

注：templates/error/ 这个的优先级比较 resources/public/error/高

WebController

@Controller
@RequestMapping(value = "/web")
public class WebController {
    private org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(WebController.class);
    @RequestMapping(value = "error")
    public String error(ModelMap map) {
        throw new RuntimeException("测试异常");
    }
}

@ControllerAdvice

WebController同上

BizException

@ControllerAdvice
public class BizException {
    private static final Logger logger = LoggerFactory.getLogger(BizException.class);
    /**
     * 统一异常处理
     */
    @ExceptionHandler({ RuntimeException.class })
    @ResponseStatus(HttpStatus.OK)
    public ModelAndView processException(RuntimeException exception) {
        logger.info("自定义异常处理-RuntimeException");
        ModelAndView m = new ModelAndView();
        m.addObject("demoException", exception.getMessage());
        m.setViewName("error/500");
        return m;
    }

    /**
     * 统一异常处理
     */
    @ExceptionHandler({ Exception.class })
    @ResponseStatus(HttpStatus.OK)
    public ModelAndView processException(Exception exception) {
        logger.info("自定义异常处理-Exception");
        ModelAndView m = new ModelAndView();
        m.addObject("demoException", exception.getMessage());
        m.setViewName("error/500");
        return m;
    }
}

500.ftl

<!DOCTYPE html>
<html>
<head lang="en">
    <title>Spring Boot Demo - exception</title>
</head>
<body>
<h1>500-系统错误</h1>
<h1>${demoException}</h1>
</body>
</html>