初识freemarker

1、添加依赖

<dependency>
    <groupId>org.freemarker</groupId>
    <artifactId>freemarker</artifactId>
    <version>2.3.23</version>
</dependency>

2、freemarker基本使用

a、freemarker工具类

/**
 * Created by r.x on 2019/4/13.
 */
public class FtlTool {

    private FtlTool() {

    }

    public static StringWriter process(Map<String, Object> data) throws IOException, TemplateException {
        Configuration configuration = new Configuration(Configuration.getVersion());
        configuration.setClassLoaderForTemplateLoading(FtlTool.class.getClassLoader(), "ftl");
        configuration.setDefaultEncoding("utf-8");
        // 添加自定义函数
        configuration.setSharedVariable(Score2GradeMethod.METHOD_NAME, new Score2GradeMethod());
        Template template = configuration.getTemplate("test.ftl");
        StringWriter writer = new StringWriter();
        template.process(data, writer);
        return writer;
    }
}

b、自定义函数

/**
 * Created by r.x on 2019/4/13.
 */
public class Score2GradeMethod implements TemplateMethodModelEx {
    public static final String METHOD_NAME = "score2Grade";

    @Override
    public Object exec(List arguments) throws TemplateModelException {
        if (arguments.get(0) instanceof SimpleNumber) {
            SimpleNumber number = (SimpleNumber) arguments.get(0);
            if (number.getAsNumber().doubleValue() > 80) {
                return "优秀";
            } else {
                return "还行";
            }
        }
        return null;
    }
}

c、测试freemarker

/**
 * Created by r.x on 2019/4/13.
 */
public class Demo {

    public static void main(String[] args) throws IOException, TemplateException {
        Map<String, Object> data = new HashMap<>();
        data.put("id", "10086");
        data.put("name", "张三");
        data.put("age", 18);
        data.put("salary", 12306.98765);
        data.put("score", 90);
        StringWriter stringWriter = FtlTool.process(data);
        // 输出执行结果
        System.out.println(stringWriter.toString());
        stringWriter.flush();
        stringWriter.close();
    }

}

d、模板文件：test.ftl

"person_info": {
    "id": "${id}",
    "name": "${name}",
    "age": ${age},
    "salary": "${salary}",
    "grade": "${score2Grade(score)}"
}

e、执行结果

"person_info": {
    "id": "10086",
    "name": "张三",
    "age": 18,
    "salary": "12,306.988",
    "grade": "优秀"
}

f、项目结构

项目结构

4、附注

freemarker语法