依赖

            <freemarker.version>2.3.28</freemarker.version>
            <dependency>
                <groupId>org.freemarker</groupId>
                <artifactId>freemarker</artifactId>
                <version>${freemarker.version}</version>
            </dependency>

简单使用

        String dir="/XXX/src/main/resources";
        Configuration conf = new Configuration();
        //加载模板文件(模板的路径)
        conf.setDirectoryForTemplateLoading(new File(dir));
        // 加载模板
        Template template = conf.getTemplate("/demo.ftl");
        // 定义数据
        Map root = new HashMap();
        root.put("world", "Hello World");
        // 定义输出
        Writer out = new FileWriter(dir + "/demo.html");
        template.process(root, out);
        System.out.println("转换成功");
        out.flush();
        out.close();

bean配置

<bean id="freemarkerConfiguration" class="org.springframework.ui.freemarker.FreeMarkerConfigurationFactoryBean">
        <property name="templateLoaderPath" value="/WEB-INF/views/message"/>
        <property name="freemarkerSettings">
            <props>
                <prop key="template_update_delay">0</prop>
                <prop key="default_encoding">UTF-8</prop>
                <prop key="locale">zh_CN</prop>
            </props>
        </property>
    </bean>


@Component
public class  FreeMarkerTemplateUtil {
    private static final Logger log = LoggerFactory.getLogger(FreeMarkerTemplateUtil.class);

    @Resource
    private Configuration freemarkerConfiguration;

    public String processTemplateIntoString(String fileName, Map<String,Object> data){
        try {
            Template t = freemarkerConfiguration.getTemplate(fileName);
            String body = FreeMarkerTemplateUtils.processTemplateIntoString(t, data);
            return body;
        } catch (IOException e) {
            log.error(e.getMessage(),e);
            throw new RuntimeException(e.toString(),e);
        } catch (TemplateException e) {
            log.error(e.getMessage(), e);
            throw new RuntimeException(e.toString(),e);
        }
    }

}

字符串加载

如果我想把模板存放到数据库中，可以实现吗？答案是肯定的。在这里可以使用StringTemplateLoader来加载模板内容。主要的代码实现如下所示：
Configuration cfg = new Configuration(); 
StringTemplateLoader stringLoader = new StringTemplateLoader();  
String templateContent="hello ${name}!";  
stringLoader.putTemplate("myTemplate",templateContent);  
cfg.setTemplateLoader(stringLoader);  
Template template = cfg.getTemplate("myTemplate","utf-8");