简单的freemarker解析测试

本文是一个很简单很基础的Freemarker模板解析测试类，复杂的也是在此基础上添加一些代码优化而来，懂得基础流程后就能融会贯通了

POM：

<dependency>
  <groupId>org.freemarker</groupId>
  <artifactId>freemarker</artifactId>
  <version>2.3.9</version>
</dependency>

JAVA:

import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.Reader;
import java.io.Writer;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;

import freemarker.template.Template;
import freemarker.template.TemplateException;

/**
 * Freemarker测试类
 *
 * @author yzl
 * @see [相关类/方法]（可选）
 * @since [产品/模块版本] （可选）
 */
public class FreemarkerTest {
    public static void main(String[] args) throws IOException, TemplateException {
        Reader reader = new FileReader(new File("E:/test.ftl"));
        Template template = new Template("test", reader, null, "utf-8");
        
        Map<Object, Object> data = new HashMap<Object, Object>();
        data.put("userName", "hello world");
        data.put("list", Arrays.asList("entity1","entity2"));
        Writer writer = new PrintWriter(System.out);
        
        template.process(data, writer);
        
        writer.flush();
        writer.close();
        reader.close();
    }
}

Ftl文件：

<p>姓名：${userName}</p>
<p>List:
<#list list as entity>
    ${entity}</br>
</#list>
</p>

输出结果：

<p>姓名：hello world</p>
<p>List:
    entity1</br>
    entity2</br>
</p>

解析Freemark字符串和ftl文件到字符串：

 package com.longge.util;

import java.io.File;
import java.io.FileReader;
import java.io.Reader;
import java.io.StringWriter;
import java.util.Map;

import freemarker.template.Template;
import lombok.NonNull;

/**
 * @author roger yang
 * @date 7/04/2019
 */
public class TemplateUtils {
    /**
     * parsing string
     * @param toParseStr
     * @param data
     * @return
     * @throws Exception
     */
    public static String parsingString(@NonNull String toParseStr, @NonNull Map<String, Object> data) throws Exception {
        try(StringWriter sw = new StringWriter();) {
            Template template = new Template(toParseStr, toParseStr, null);
            
            template.process(data, sw);
            sw.flush();
            return sw.toString();
        }
    }
    
    /**
     * parsing with ftl file
     * @param file
     * @param data
     * @return
     * @throws Exception
     */
    public static String parsingFtlFile(@NonNull File file, @NonNull Map<String, Object> data) throws Exception {
        try(Reader reader = new FileReader(file);
            StringWriter sw = new StringWriter();) {
            Template template = new Template(file.getName(), reader, null);
            template.process(data, sw);
            sw.flush();
            return sw.toString();
        }
    }
    
    /**
     * parsing with ftl file
     * @param file
     * @param data
     * @return
     * @throws Exception
     */
    public static String parsingFtlFile(@NonNull String filePath, @NonNull Map<String, Object> data) throws Exception {
        File file = new File(filePath);
        return parsingFtlFile(file, data);
    }
}