Java动态编译

2016-02-11· 1043 次浏览
```java package net.xsoftlab.baike; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.net.URI; import java.net.URISyntaxException; import java.util.Arrays; import java.util.List; import javax.tools.JavaCompiler; import javax.tools.JavaCompiler.CompilationTask; import javax.tools.SimpleJavaFileObject; import javax.tools.StandardJavaFileManager; import javax.tools.ToolProvider; public class Compile {     public static void main(String[] args) throws IOException, URISyntaxException {         Compile.execute(null);     }     public static String execute(String code) throws IOException, URISyntaxException {         String source = "public class Main {" + code + "}";         JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();         StandardJavaFileManager fileManager = compiler.getStandardFileManager(null, null, null);         StringSourceJavaObject sourceObject = new Compile.StringSourceJavaObject("Main", source);         List<StringSourceJavaObject> fileObjects = Arrays.asList(sourceObject);         CompilationTask task = compiler.getTask(null, fileManager, null, null, null, fileObjects);         boolean result = task.call();         if (result) {             System.out.println("Compile succeeded!");         } else {             System.out.println("Compile failed!");         }         // 运行程序         Runtime run = Runtime.getRuntime();         Process process = run.exec("java -cp ./ Main");         InputStream in = process.getInputStream();         BufferedReader reader = new BufferedReader(new InputStreamReader(in));         String info = "";         StringBuffer bu = new StringBuffer();         while ((info = reader.readLine()) != null) {             bu.append(info);         }         return bu.toString();     }     static class StringSourceJavaObject extends SimpleJavaFileObject {         private String content = null;         public StringSourceJavaObject(String name, String content) throws URISyntaxException {             super(URI.create("string:///" + name.replace('.', '/') + Kind.SOURCE.extension), Kind.SOURCE);             this.content = content;         }         @Override         public CharSequence getCharContent(boolean ignoreEncodingErrors) throws IOException {             return content;         }     } } ```