java 几个不错的编译器

janino以及javacc是不错的选择，都是好多框架的选择

janino 参考使用

  • pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
 
    <groupId>com.dalong</groupId>
    <artifactId>javacapp</artifactId>
    <version>1.0-SNAPSHOT</version>
 
    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.codehaus.janino</groupId>
            <artifactId>janino</artifactId>
            <version>3.1.3</version>
        </dependency>
        <dependency>
            <groupId>me.nimavat</groupId>
            <artifactId>shortid</artifactId>
            <version>1.0.1.RC1</version>
        </dependency>
    </dependencies>
 
    <repositories>
        <repository>
            <id>demo</id>
            <url>http://dl.bintray.com/snimavat/maven</url>
        </repository>
    </repositories>
</project>
  • main
package com.dalong;
 
import org.codehaus.commons.compiler.CompileException;
import org.codehaus.janino.ScriptEvaluator;
import java.lang.reflect.InvocationTargetException;
import java.util.Arrays;
 
public class App {
    static void method1(String item) {
        System.out.printf(item);
    }
    public static void main(String[] args) throws CompileException, InvocationTargetException {
        ScriptEvaluator se = new ScriptEvaluator();
        se.cook(
                ""
                        + "static void method1() {
"
                        + "    System.out.println(1);
"
                        + "}
"
                        + "
"
                        + "method1();
"
                        + "method2();
"
                        + "
"
                        + "static void method2() {
"
                        + " System.out.println(me.nimavat.shortid.ShortId.generate().toString());
"
                        + "}
"
        );
        Arrays.stream(se.getDefaultImports()).iterator().forEachRemaining(App::method1);
        se.evaluate(new Object[0]);
    }
}

javacc

javacc 的使用就有点复杂了，需要定义自己的schema 然后进行代码生成

 
#!/bin/sh
java -classpath javacc.jar javacc "$@"
  • 创建一个简单的schema
options {
    STATIC = false;
}
 
PARSER_BEGIN(Adder)
import java.io.*;
 
class Adder {
    public static void main(String[] args) {
        for (String arg : args) {
            try {
                System.out.println(evaluate(arg));
            } catch (ParseException ex) {
                System.err.println(ex.getMessage());
            }
        }
    }
 
    public static long evaluate(String src) throws ParseException {
        Reader reader = new StringReader(src);
        return new Adder(reader).expr();
    }
}
PARSER_END(Adder)
 
SKIP: { <[" ", "	", "
", "
"]> }
 
TOKEN: {
    <INTEGER: (["0"-"9"])+>
}
 
long expr():
{
    Token x, y;
}
{
    x=<INTEGER> "+" y=<INTEGER> <EOF>
    {
        return Long.parseLong(x.image) + Long.parseLong(y.image);
    }
}
  • 生成代码
./javacc app.jj
  • 效果

  • 编译执行

javac Adder.java
java Adder 1+2

参考资料

https://github.com/javacc/javacc
https://github.com/janino-compiler/janino
https://github.com/apache/calcite/blob/master/core/src/main/codegen/templates/Parser.jj

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原文地址：https://www.cnblogs.com/rongfengliang/p/14407618.html