springboot中freemarker怎么生成文件

在Spring Boot中使用FreeMarker生成文件的步骤如下：

添加FreeMarker依赖：在pom.xml文件中添加FreeMarker的依赖：

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

创建FreeMarker配置类：新建一个配置类用于配置FreeMarker的模板路径和其他配置：

@Configurationpublic class FreeMarkerConfig {    @Autowired    private Environment env;    @Bean    public FreeMarkerConfigurationFactoryBean freeMarkerConfiguration() {        FreeMarkerConfigurationFactoryBean bean = new FreeMarkerConfigurationFactoryBean();        bean.setTemplateLoaderPath("classpath:/templates");        Properties settings = new Properties();        settings.setProperty("template_update_delay", "0");        settings.setProperty("default_encoding", "UTF-8");        settings.setProperty("locale", "zh_CN");        settings.setProperty("number_format", "0.##########");        settings.setProperty("datetime_format", "yyyy-MM-dd HH:mm:ss");        settings.setProperty("date_format", "yyyy-MM-dd");        settings.setProperty("boolean_format", "true,false");        settings.setProperty("time_format", "HH:mm:ss");        settings.setProperty("whitespace_stripping", "true");        settings.setProperty("auto_import", "ftl/common/common.ftl as common,ftl/common/functions.ftl as fun");        settings.setProperty("url_escaping_charset", "UTF-8");        settings.setProperty("output_format", "HTMLOutputFormat");        settings.setProperty("tag_syntax", "auto_detect");        settings.setProperty("template_exception_handler", "rethrow");        settings.setProperty("classic_compatible", "true");        bean.setFreemarkerSettings(settings);        return bean;    }    @Bean    public FreeMarkerConfigurer freeMarkerConfigurer() throws IOException {        FreeMarkerConfigurer configurer = new FreeMarkerConfigurer();        configurer.setConfiguration(freeMarkerConfiguration().getObject());        return configurer;    }    @Bean    public FreeMarkerViewResolver freeMarkerViewResolver() {        FreeMarkerViewResolver resolver = new FreeMarkerViewResolver();        resolver.setCache(false);        resolver.setSuffix(".ftl");        resolver.setContentType("text/html; charset=UTF-8");        resolver.setRequestContextAttribute("request");        resolver.setExposeSpringMacroHelpers(true);        return resolver;    }}

创建模板文件：在src/main/resources/templates目录下创建FreeMarker模板文件（例如example.ftl）。

创建Controller：创建一个Controller类用于接收请求，并在请求处理方法中使用FreeMarker生成文件，例如：

@Controllerpublic class FileController {    @Autowired    private Configuration configuration;    @GetMapping("/generate")    public ResponseEntity<Resource> generateFile() throws Exception {        // 获取模板        Template template = configuration.getTemplate("example.ftl");                // 创建数据模型        Map<String, Object> data = new HashMap<>();        data.put("name", "John Doe");        data.put("age", 30);        // 创建输出流        StringWriter writer = new StringWriter();        template.process(data, writer);        // 生成文件        byte[] bytes = writer.toString().getBytes();        ByteArrayResource resource = new ByteArrayResource(bytes);                return ResponseEntity.ok()                .contentLength(bytes.length)                .contentType(MediaType.APPLICATION_OCTET_STREAM)                .body(resource);    }}

在上述代码中，使用Configuration类获取模板对象，并将数据模型填充到模板中，最后使用ByteArrayResource返回生成的文件。

访问生成文件：启动Spring Boot应用，访问http://localhost:8080/generate即可生成文件并下载。

通过以上步骤，您可以在Spring Boot中使用FreeMarker生成文件。