我想在 java 中创建一个模板文件,我使用 Eclipse IDE。我想创建一个模板文件,这样一个从用户那里获取参数的程序应该能够将这些参数粘贴到模板文件中,然后将其保存为单独的文件。我怎样才能做到这一点 ?
请指导我。
谢谢 注意
这是在我的开源模板引擎Chunk中执行此操作的方法。
import com.x5.template.Theme;
import com.x5.template.Chunk;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
...
public void writeTemplatedFile() throws IOException
{
Theme theme = new Theme();
Chunk chunk = theme.makeChunk("my_template", "txt");
// replace static values below with user input
chunk.set("name", "Lancelot");
chunk.set("favorite_color", "blue");
String outfilePath = getFilePath();
File file = new File(outfilePath);
FileWriter out = new FileWriter(file);
chunk.render(out);
out.flush();
out.close();
}
my_template.txt(只需放置在主题/my_template.txt 中的类路径中)
My name is {$name}.
My favorite color is {$favorite_color}.
输出:
My name is Lancelot.
My favorite color is blue.
通过添加 |filters 和 :defaults 到您的标签,您的模板可以变得更智能。
my_template.txt - 示例 2
My name is {$name|defang:[not provided]}.
My favorite color is {$favorite_color|defang|lc:[not provided]}.
在此示例中,defang
过滤器会删除任何可能有助于形成 XSS 攻击的字符。过滤器将lc
文本更改为小写。如果值为空,则将输出冒号之后的任何内容。
有一个Eclipse 插件可用于直接在 Eclipse IDE 中编辑块模板。该插件为模板文档提供语法高亮和大纲视图。
Chunk 可以做的更多,请查看文档以进行快速浏览。完全披露:我喜欢 Chunk 的部分原因是我创造了它。
让我们把它分成几个步骤:
从用户那里获取输入参数:
然而,如果您这样做(向 servlet 发送请求、使用 CLI 或将参数传递给 main 方法),您将需要在某种对象或数据结构中捕获输入。为此,我将创建一个简单的 pojo 类,如下所示:
public class UserInput
{
protected String firstName;
protected String lastName;
public String getFirstName()
{
return firstName;
}
public void setFirstName(String firstName)
{
this.firstName = firstName;
}
public String getLastName()
{
return lastName;
}
public void setLastName(String lastName)
{
this.lastName = lastName;
}
}
这很方便,因此您可以尝试多个模板库。使用界面也是最佳实践,这样您就可以轻松改变主意并切换到不同的库。我最喜欢的库是freemarker和mustache。这是一个演示其常见流程的界面示例。
public interface ITemplateEngine
{
/**
* creates the template engines instance and sets the root path to the templates in the resources folder
* @param templatesResouceFolder
*/
public void init(String templatesResouceFolder);
/**
* sets the current template to use in the process method
* @param template
*/
public void setTemplate(String template);
/**
* compiles and writes the template output to a writer
* @param writer
* @param data
*/
public void process(Writer writer, Object data);
/**
* returns the template file extension
* @return
*/
public String getTemplateExtension();
/**
* finishes the write process and closes the write buffer
*/
public void flush();
}
第一个是freemarker模板的例子......
/**
* This class is a freemarker implementation of ITemplateEngine
* Use ${obj.prop} in your template to replace a certain the token
* Use ${obj.prop!} to replace with empty string if obj.prop is null or undefined
*
*
*/
public class FreemarkerTemplateEngine implements ITemplateEngine
{
protected Configuration instance = null;
protected String templatesFolder = "templates";
protected Template templateCompiler = null;
protected Writer writer = null;
@Override
public void init(String templatesResouceFolder)
{
if(instance == null){
instance = new Configuration();
instance.setClassForTemplateLoading(this.getClass(), "/");
this.templatesFolder = templatesResouceFolder;
}
}
@Override
public void setTemplate(String template)
{
try
{
templateCompiler = instance.getTemplate(templatesFolder + File.separatorChar + template + getTemplateExtension());
} catch (IOException ex)
{
Logger.getLogger(FreemarkerTemplateEngine.class.getName()).log(Level.SEVERE, null, ex);
}
}
@Override
public void process(Writer writer, Object data)
{
try
{
templateCompiler.process(data, writer);
this.writer = writer;
} catch (TemplateException | IOException ex)
{
Logger.getLogger(FreemarkerTemplateEngine.class.getName()).log(Level.SEVERE, null, ex);
}
}
@Override
public String getTemplateExtension()
{
return ".ftl";
}
@Override
public void flush()
{
try
{
this.writer.flush();
} catch (IOException ex)
{
Logger.getLogger(FreemarkerTemplateEngine.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
这是一个小胡子模板引擎的例子......
/**
*
* Use {{obj.prop}} in your template to replace a certain the token
* If obj.prop is null or undefined, it will automatically replace it with an empty string
* If you want to exclude an entire section based on if a value is null, undefined, or false you can do this:
* {{#obj.prop}}
* Never shown
* {{/obj.prop}}
*/
public class MustacheTemplateEngine implements ITemplateEngine
{
protected MustacheFactory factory = null;
protected Mustache instance = null;
protected Writer writer = null;
protected String templatesFolder = "templates";
@Override
public void init(String templatesResouceFolder)
{
if(factory == null){
factory = new DefaultMustacheFactory();
this.templatesFolder = templatesResouceFolder;
}
}
@Override
public void setTemplate(String template)
{
instance = factory.compile(templatesFolder + File.separatorChar + template + getTemplateExtension());
}
@Override
public void process(Writer writer, Object data)
{
this.writer = instance.execute(writer, data);
}
@Override
public String getTemplateExtension()
{
return ".mustache";
}
@Override
public void flush()
{
try
{
this.writer.flush();
} catch (IOException ex)
{
Logger.getLogger(MustacheTemplateEngine.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
Freemarker 模板具有“.ftl”扩展名,而 mustache 模板具有“.mustache”扩展名。让我们创建一个名为“test.mustache”的小胡子模板,并将其放在“资源/模板”文件夹中。
Hello {{firstName}} {{lastName}}!
创建 JUnit 测试总是一个好主意
public class JavaTemplateTest
{
ITemplateEngine templateEngine = new MustacheTemplateEngine();
public File outputFolder = new File(System.getProperty("user.home") + "/JavaTemplateTest");
@Before
public void setUp()
{
outputFolder.mkdirs();
}
@After
public void tearDown()
{
for (File file : outputFolder.listFiles())
{
file.delete();
}
outputFolder.delete();
}
public JavaTemplateTest()
{
}
@Test
public void testTemplateEngine() throws Exception
{
//mock the user input
UserInput userInput = new UserInput();
userInput.setFirstName("Chris");
userInput.setLastName("Osborn");
//create the out put file
File file = new File(outputFolder.getCanonicalPath() + File.separatorChar + "test.txt");
//create a FileWriter
try (Writer fileWriter = new FileWriter(file.getPath()))
{
//put the templateEngine to work
templateEngine.init("templates");
templateEngine.setTemplate("test"); //resources/templates/test.mustache
templateEngine.process(fileWriter, userInput); //compile template
templateEngine.flush(); //write to file
}
//Read from the file and assert
BufferedReader buffer = new BufferedReader(new FileReader(file));
Assert.assertEquals("Hello Chris Osborn!", buffer.readLine());
}
}
基本上就是这样。mvn install
如果您使用 maven 进行设置,则测试应该在运行目标时运行并通过。
这是我为此示例创建的项目代码:https ://github.com/cosbor11/java-template-example
希望能帮助到你!