OpenJDK Project Amber
Amber 项目的目标是探索和孵化较小的、面向生产环境的 Java 语言特性。这些特性已经作为候选 JEP 被接受。
Amber 项目相关的特性在成为 Java 官方平台的一部分之前，要通过两轮的预览测试。对于一个特性，每轮预览测试和最终的标准化都有单独的提案。
下文分别描述了 Amber 项目相关的每个特性。
JEP 430: 模板字符串
STR 模板处理器
示例代码
import java.util.Date;
public class Main {
private static class Req {
private Date date;
private String ip;
private String path;
public Req(Date date, String ip, String path) {
this.date = date;
this.ip = ip;
this.path = path;
}
public String getPath() {
return path;
}
}
public static void main(String[] args) {
// 1. Embedded expressions can be strings.
String firstName = "Bill";
String lastName = "Duck";
String fullName = STR."\{firstName} \{lastName}";
System.out.println(fullName);
// 2. Embedded expressions can perform arithmetic
int x = 10, y = 20;
String s = STR."\{x} + \{y} = \{x + y}";
System.out.println(s);
// 3. Embedded expressions can invoke methods and access fields
Req req = new Req(new Date(), "192.168.1.1", "/index.html");
String t = STR."Access \{req.getPath()} at \{req.date} from \{req.ip}";
System.out.println(t);
}
}
运行结果
[optor666.github.io]$javac --enable-preview -source 21 Main.java
Note: Main.java uses preview features of Java SE 21.
Note: Recompile with -Xlint:preview for details.
[optor666.github.io]$java --enable-preview Main
Bill Duck
10 + 20 = 30
Access /index.html at Fri Dec 15 11:47:42 CST 2023 from 192.168.1.1
[optor666.github.io]$