日常总结2015-03-10

1、在调用javac 时候会报错误: 编码GBK的不可映射字；

2、执行Runtime.getRuntime().exec()没有反应，没有返回，被hang住了

import java.util.*;
import java.io.*;
public class MediocreExecJavac
{
public static void main(String args[])
{
try
{
Runtime rt = Runtime.getRuntime();
Process proc = rt.exec("javac");
InputStream stderr = proc.getErrorStream();
InputStreamReader isr = new InputStreamReader(stderr);
BufferedReader br = new BufferedReader(isr);
String line = null;
System.out.println("<ERROR>");
while ( (line = br.readLine()) != null)
System.out.println(line);
System.out.println("</ERROR>");
int exitVal = proc.waitFor();
System.out.println("Process exitValue: " + exitVal);
} catch (Throwable t)
{
t.printStackTrace();
}
}
}

3、数组合并

T[] concat(T[] A, T[] B) {
T[] C= new T[A.length+B.length];
System.arraycopy(A, 0, C, 0, A.length);
System.arraycopy(B, 0, C, A.length, B.length);

return C;
}

4、获取当前工程的路径

System.getProperty("user.dir")