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：

1. 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> 

2. 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：

@Configuration public 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;     }  } 

3. 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）。

4. 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：

@Controller public 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。

5. 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。