Freemarker基本使用

文章链接:http://www.liuschen.com

Freemarker

导入Freemarker的jar包

生成Java代码

/**
 * 生成Java代码
 * */
public static void generateJavaCode(){
	

	String templateFile = "src/demo_java.ftl";
	String targetFile = "src/com/luofeng/Person.java";
	
	Map<String, Object> map = new HashMap<String, Object>();

	map.put("packageName", "com.luofeng");
	map.put("className", "Person");
	map.put("author", "luofeng");

	
    List<Attribute> attr_list = new ArrayList<Attribute>();
    attr_list.add(new Attribute("id", "Long"));
    attr_list.add(new Attribute("name", "String"));
    attr_list.add(new Attribute("age", "Integer"));
    attr_list.add(new Attribute("hobby", "List<String>"));

    map.put("attrs", attr_list);
    
    Configuration configuration = new Configuration();
	
	try {
		Template template = configuration.getTemplate(templateFile);
		template.setEncoding("UTF-8");
		Writer out = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(targetFile), "UTF-8"));  
        template.process(map, out);
        out.flush();
        out.close();
	} catch (IOException e) {
		e.printStackTrace();
	} catch (TemplateException e) {
		e.printStackTrace();
	}
    
}

Java的ftl模板文件

package ${packageName};

import java.util.List;

/**
 *  @author ${author}
 */
public class ${className} {
    <#list attrs as attr> 
    private ${attr.value!"meizhi"} ${attr.name};
    </#list>

    <#list attrs as attr>
    public void set${attr.name?cap_first}(${attr.value!"meizhi"} ${attr.name}){
        this.${attr.name} = ${attr.name};
    }
    public ${attr.value!"meizhi"} get${attr.name?cap_first}(){
        return this.${attr.name};
    }

    </#list>
}

其中

<h1>Welcome ${user!"Anonymous"}!</h1>

可以为替换的变量设置默认值，因为变量为空会直接崩溃掉

<#if user??><h1>Welcome ${user}!</h1></#if>

可以判断变量是否存在，不存在的话会忽略掉整个代码段

生成Html代码

/**
 * 生成Html代码
 * */
public void generateHtmlCode(){
	String templateFile = "src/demo_html.ftl";
	String targetFile = "src/html.html";
	
	Map map = new HashMap<String, String>();
	map.put("message", "hello world");
	map.put("name", "java小强");
	
	Configuration configuration = new Configuration();
	
	try {
		Template template = configuration.getTemplate(templateFile);
		template.setEncoding("UTF-8");
		Writer out = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(targetFile), "UTF-8"));  
        template.process(map, out);
        out.flush();
        out.close();
	} catch (IOException e) {
		e.printStackTrace();
	} catch (TemplateException e) {
		e.printStackTrace();
	}
}

对应的ftl模板

<html>  
  <head>  
        <title>freemarker是什么</title>  
    </head>  
    <body>  
        <h1>${message},${name}</h1>  
    </body>  
</html>

需要注意的是，在代码中我设置的编码格式是UTF-8,但是eclipse默认打开文件的编码格式可能是gbk,如果这个全局值不修改，直接打开生成的文件就会乱码，位置是在：

window->Preferences->General->Workspace->Text file encoding
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