java - Simple way templating multiline strings in java code

Question

I'm often run in to the following situation: I have long multiline strings where properties must be injected - e.g. something like templating. But I don't want to inlcude a complete templating engine (like velocity or freemarker) in my projects.

How can this be done in a simple way:

String title = "Princess";
String name  = "Luna";
String community = "Stackoverflow";

String text =
   "Dear " + title + " " + name + "!\n" +  
   "This is a question to " + community + "-Community\n" + 
   "for simple approach how to code with Java multiline Strings?\n" + 
   "Like this one.\n" + 
   "But it must be simple approach without using of Template-Engine-Frameworks!\n" + 
   "\n" + 
   "Thx for ...";

score 5 · Accepted Answer

您可以使用几行代码创建自己的小型且简单的模板引擎：

public static void main(String[] args) throws IOException {

    String title = "Princes";
    String name  = "Luna";
    String community = "Stackoverflow";

    InputStream stream = DemoMailCreater.class.getResourceAsStream("demo.mail");


    byte[] buffer = new byte[stream.available()];
    stream.read(buffer);

    String text = new String(buffer);

    text = text.replaceAll("§TITLE§", title);
    text = text.replaceAll("§NAME§", name);
    text = text.replaceAll("§COMMUNITY§", community);

    System.out.println(text);

}

和小文本文件，例如在同一个文件夹（包）中demo.mail：

Dear §TITLE§ §NAME§!
This is a question to §COMMUNITY§-Community
for simple approach how to code with Java multiline Strings? 
Like this one.
But it must be simple approach without using of Template-Engine-Frameworks!

Thx for ...

score 2 · Accepted Answer

一种基本的方法是使用String.format(...)

例子：

String title = "Princess";
String name  = "Celestia";
String community = "Stackoverflow";

String text = String.format(
    "Dear %s %s!%n" +  
    "This is a question to %s-Community%n" + 
    "for simple approach how to code with Java multiline Strings?%n" + 
    "Like this one.%n" + 
    "But it must be simple approach without using of Template-Engine-Frameworks!%n" + 
    "%n" + 
    "Thx for ...", title, name, community);

更多信息

score 1 · Accepted Answer

您可以在此处Java Resources使用以实现它，或者您可以使用不同的方法保持当前使用的方法，例如此处

score 0 · Accepted Answer

Java 没有对模板的内置支持。您的选择是：

使用现有的模板框架/引擎，
构建您自己的模板框架/引擎（或类似的），或
写很多“字符串抨击”代码......就像你的问题一样。

您可以使用String.format(...),MessageFormat和类似的方法更简洁地编写上面的代码，但它们不会让您走得太远......除非您的模板非常简单。

相比之下，一些语言内置了对字符串插值、“here”文档或可以适应模板的简洁结构构建语法的支持。

score 0 · Accepted Answer

您可以java.text.MessageFormat为此使用：

String[] args = {"Princess", "Luna", "Stackoverflow"};
String text = MessageFormat.format("Bla bla, {1}, and {2} and {3}", args);

score 0 · Accepted Answer

您可以使用String#format()：

String title = "Princess";
String name  = "Luna";
String community = "Stackoverflow";
String text = String.format("Dear %s %s!\n" +  
            "This is a question to %s-Community\n" + 
            "for simple approach how to code with Java multiline Strings?\n" + 
            "Like this one.\n" + 
            "But it must be simple approach without using of Template-Engine-Frameworks!\n" + 
            "\n" +
            "Thx for ...", title, name, community);

score 0 · Accepted Answer

使用 Java 15+：

String title = "Princess";
String name = "Luna";
String community = "Stackoverflow";

String text = """
        Dear %s %s!
        This is a question to %s-Community
        for simple approach how to code with Java multiline Strings?
        """.formatted(title, name, community);

java - Simple way templating multiline strings in java code

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