使用这个库

https://github.com/alessio-santacroce/multiline-string-literals

可以这样写

System.out.println(newString(/*
      Wow, we finally have
      multiline strings in
      Java! HOOO!
*/));

很好很简单，但是只适用于单元测试

我建议使用ThomasP所建议的实用程序，然后将其链接到构建过程中。仍然存在一个外部文件以包含文本，但在运行时不读取该文件。 工作流程如下:

构建一个“文本文件到java代码”实用程序并检查到版本控制 在每次构建时，针对资源文件运行实用程序以创建修改后的java源 Java源代码包含类似于 类TextBlock{…后面跟着一个从资源文件自动生成的静态字符串 用剩下的代码构建生成的java文件

注意:这个答案适用于Java 14及以上版本。

Java 15引入了文本块(多行文字)。详情请看这个答案。

听起来像是要做一个多行文字，这在Java中是不存在的。

你最好的选择是用+ d组合的字符串。人们提到的一些其他选项(StringBuilder, String。format, String.join)只有当你从一个字符串数组开始时才更可取。

考虑一下:

String s = "It was the best of times, it was the worst of times,\n"
         + "it was the age of wisdom, it was the age of foolishness,\n"
         + "it was the epoch of belief, it was the epoch of incredulity,\n"
         + "it was the season of Light, it was the season of Darkness,\n"
         + "it was the spring of hope, it was the winter of despair,\n"
         + "we had everything before us, we had nothing before us";

与StringBuilder:

String s = new StringBuilder()
           .append("It was the best of times, it was the worst of times,\n")
           .append("it was the age of wisdom, it was the age of foolishness,\n")
           .append("it was the epoch of belief, it was the epoch of incredulity,\n")
           .append("it was the season of Light, it was the season of Darkness,\n")
           .append("it was the spring of hope, it was the winter of despair,\n")
           .append("we had everything before us, we had nothing before us")
           .toString();

与String.format ():

String s = String.format("%s\n%s\n%s\n%s\n%s\n%s"
         , "It was the best of times, it was the worst of times,"
         , "it was the age of wisdom, it was the age of foolishness,"
         , "it was the epoch of belief, it was the epoch of incredulity,"
         , "it was the season of Light, it was the season of Darkness,"
         , "it was the spring of hope, it was the winter of despair,"
         , "we had everything before us, we had nothing before us"
);

相对于Java8 String.join():

String s = String.join("\n"
         , "It was the best of times, it was the worst of times,"
         , "it was the age of wisdom, it was the age of foolishness,"
         , "it was the epoch of belief, it was the epoch of incredulity,"
         , "it was the season of Light, it was the season of Darkness,"
         , "it was the spring of hope, it was the winter of despair,"
         , "we had everything before us, we had nothing before us"
);

如果您想在特定的系统中使用换行符，您要么需要使用system . lineseparator()，要么可以在String.format中使用%n。

另一种选择是将资源放在文本文件中，只读取该文件的内容。对于非常大的字符串，这将是可取的，以避免不必要地膨胀您的类文件。

我知道这是一个老问题，但是对于感兴趣的开发人员来说，多行文字将在#Java12中

http://mail.openjdk.java.net/pipermail/amber-dev/2018-July/003254.html

我还没有看到的另一个答案是java.io.PrintWriter。

StringWriter stringWriter = new StringWriter();
PrintWriter writer = new PrintWriter(stringWriter);
writer.println("It was the best of times, it was the worst of times");
writer.println("it was the age of wisdom, it was the age of foolishness,");
writer.println("it was the epoch of belief, it was the epoch of incredulity,");
writer.println("it was the season of Light, it was the season of Darkness,");
writer.println("it was the spring of hope, it was the winter of despair,");
writer.println("we had everything before us, we had nothing before us");
String string = stringWriter.toString();

此外，java.io.BufferedWriter有一个newLine()方法的事实也未被提及。

我所知道的唯一方法是用加号连接多行