Java6的新特性

Posted 2020-10-08 流星<。)#)))≦

tags:

篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了Java6的新特性相关的知识，希望对你有一定的参考价值。

原文出处：xixicat

序

本文梳理了下java6的新特性，相对于java5而言，java6的特性显得少些，分量也不那么重，相当于java5是windows xp，java6有点像vista。

特性列表

JSR223脚本引擎
JSR199--Java Compiler API
JSR269--Pluggable Annotation Processing API
支持JDBC4.0规范
JAX-WS 2.0规范

1、JSR223脚本引擎

Scripting for the Java Platform

基本使用

public class BasicScripting {
    public void greet() throws ScriptException {
        ScriptEngineManager manager = new ScriptEngineManager();
        //支持通过名称、文件扩展名、MIMEtype查找
        ScriptEngine engine = manager.getEngineByName("javascript");
//        engine = manager.getEngineByExtension("js");
//        engine = manager.getEngineByMimeType("text/javascript");
        if (engine == null) {
            throw new RuntimeException("找不到JavaScript语言执行引擎。");
        }
        engine.eval("println(‘Hello!‘);");
    }
    public static void main(String[] args) {
        try {
            new BasicScripting().greet();
        } catch (ScriptException ex) {
            Logger.getLogger(BasicScripting.class.getName()).log(Level.SEVERE, null, ex);
        }
    }
}

绑定上下文

public class ScriptContextBindings extends JsScriptRunner {
    public void scriptContextBindings() throws ScriptException {
        ScriptEngine engine = getJavaScriptEngine();
        ScriptContext context = engine.getContext();
        Bindings bindings1 = engine.createBindings();
        bindings1.put("name", "Alex");
        context.setBindings(bindings1, ScriptContext.GLOBAL_SCOPE);
        Bindings bindings2 = engine.createBindings();
        bindings2.put("name", "Bob");
        context.setBindings(bindings2, ScriptContext.ENGINE_SCOPE);
        engine.eval("println(name);");
    }
    public void useScriptContextValues() throws ScriptException {
        ScriptEngine engine = getJavaScriptEngine();
        ScriptContext context = engine.getContext();
        Bindings bindings = context.getBindings(ScriptContext.ENGINE_SCOPE);
        bindings.put("name", "Alex");
        engine.eval("println(name);");
    }
    public void attributeInBindings() throws ScriptException {
        ScriptEngine engine = getJavaScriptEngine();
        ScriptContext context = engine.getContext();
        context.setAttribute("name", "Alex", ScriptContext.GLOBAL_SCOPE);
        engine.eval("println(name);");
    }
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) throws ScriptException {
        ScriptContextBindings scb = new ScriptContextBindings();
        scb.scriptContextBindings();
        scb.useScriptContextValues();
        scb.attributeInBindings();
    }
}

2、JSR199--Java Compiler API

public class JavaCompilerAPICompiler {
    public void compile(Path src, Path output) throws IOException {
        JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
        try (StandardJavaFileManager fileManager = compiler.getStandardFileManager(null, null, null)) {
            Iterable<? extends JavaFileObject> compilationUnits = fileManager.getJavaFileObjects(src.toFile());
            Iterable<String> options = Arrays.asList("-d", output.toString());
            JavaCompiler.CompilationTask task = compiler.getTask(null, fileManager, null, options, null, compilationUnits);
            boolean result = task.call();
        }
    }
}