`
收藏列表
标题 标签 来源
java自定义类加载器 java 自定义类加载器
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.lang.reflect.Method;

/**
 * 动态的编译Java源文件。它检查.class文件是否存在,.class文件是否比源文件陈旧。
 */
public class CompilingClassLoader extends ClassLoader {

	private String path = "";

	public CompilingClassLoader(String path) {
		this.path = path;
	}

	/**
	 * 从磁盘读取指定文件,并返回字节数组
	 */
	private byte[] getBytes(String className) {
		FileInputStream in = null;
		byte[] raw = null;
		try {
			File file = new File(className);
			in = new FileInputStream(file);
			raw = new byte[(int) file.length()];
			int r = in.read(raw);
			if (r == file.length()) {
				return raw;
			}
		} catch (IOException ex) {
		} finally {
			if (in != null) {
				try {
					in.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}
		return null;
	}

	/**
	 * 启动一个进程来编译java源文件
	 */
	private boolean compile(String javaFile) {
		try {
			Process p = Runtime.getRuntime().exec("javac " + javaFile);
			p.waitFor(); // 等待编译结束
			int res = p.exitValue(); // 检查返回码,看编译是否成功
			return res == 0;
		} catch (InterruptedException e) {
			e.printStackTrace();
		} catch (IOException ex) {
			ex.printStackTrace();
		}
		return false;
	}

	/**
	 * 动态的编译Java源文件。它检查.class文件是否存在,.class文件是否比源文件陈旧。
	 */
	protected Class<?> findClass(String className)
			throws ClassNotFoundException {
		Class<?> cls = this.findLoadedClass(className);
		if (cls == null) {
			String fileName = className.replace('.', File.pathSeparatorChar);
			String javaFileName = path + fileName + ".java";
			String classFileName = path + fileName + ".class";
			File javaFile = new File(javaFileName);
			File classFile = new File(classFileName);
			if (!classFile.exists() && javaFile.exists()
					|| javaFile.lastModified() > classFile.lastModified()) {
				if (!compile(javaFileName)) {
					throw new ClassNotFoundException(className);
				}
			}
			byte[] raw = getBytes(classFileName);
			if (raw == null) {
				throw new ClassNotFoundException(className);
			}
			cls = this.defineClass(className, raw, 0, raw.length);
		}
		return cls;
	}

	public static void main(String[] args) throws Exception{
		CompilingClassLoader ccl = new CompilingClassLoader("e:/");
		Class<?> c = ccl.findClass("Test");
		Method method = c.getDeclaredMethod("print", new Class<?>[] {});
		method.invoke(c.newInstance(), new Object[] {});
	}
}
通用toString方法 通用tostring方法
    public static String beanToString(Object bean)
    {
        Class c = bean.getClass();
        StringBuffer buffer = new StringBuffer();
        buffer.append(c.getName() + '[');
        while (true)
        {
            Field[] fields = c.getDeclaredFields();
            AccessibleObject.setAccessible(fields, true);
            try
            {
                for (int i = 0; i < fields.length; i++)
                {
                    Field f = fields[i];
                    buffer.append(f.getName());
                    buffer.append('=');
                    Object field = f.get(bean);
                    if (field instanceof Object[])
                    {
                        Object[] obj = (Object[])field;
                        buffer.append(Tool.arrayToString(obj));
                    }
                    else
                    {
                        buffer.append(field);
                    }
                    if (i + 1 < fields.length)
                    {
                        buffer.append(',');
                    }
                }
            }
            catch (Exception e)
            {
                UspLog.error("toString object error: " + e.toString());
            }
            c = c.getSuperclass();
            if (!c.equals(Object.class))
            {
                buffer.append(',');
                continue;
            }
            else
            {
                break;
            }
        }
        buffer.append(']');
        return buffer.toString();
        
    }
删除目录下所有文件以及目录 java
public static void delAllFileByFilePath(String path)
	{
		File f = new File(path);
		if(f.exists() && f.isDirectory())
		{
			if(f.listFiles().length==0)
			{
				f.delete();
			}else
			{
				File files[] =  f.listFiles();
				int i = files.length;
				for(int j= 0 ; j<i ; j++)
				{
					if(files[j].isDirectory())
					{
						delAllFileByFilePath(files[j].getAbsolutePath());
					}else
					{
						files[j].delete();
					}
				}
			}
			
		}
	}
Global site tag (gtag.js) - Google Analytics