java学习笔记—实现一个类MyInputStream（28）

public class TestDemo {
    public static void main(String[] args) throws Exception {
        InputStream in = new MyInputStream("d:/a/a.txt");
        byte[] b = new byte[1024];
        int len = 0;
        while((len=in.read(b))!=-1){
            String s = new String(b,0,len);
            System.err.print(s);
        }
        in.close();
    }
}

class MyInputStream extends InputStream {  //成为inputstream的子类，即is a.
    private InputStream in; 
    public MyInputStream(String fileName) {
        try {
            in = new FileInputStream(fileName);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }
    public int read(byte[] b){
        int len=-1;
        try {
            len = in .read(b);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return len;
    }
    public void close(){
        try {
            in.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    @Override
    public int read() throws IOException {
        return 0;
    }
}

public class MyDataSource implements DataSource  {
    private LinkedList<Connection> pool = new LinkedList<Connection>();
    public MyDataSource() {
        try {
            Class.forName("com.mysql.jdbc.Driver");
            String url = "jdbc:mysql:///db909?characterEncoding=UTf8";
            for (int i = 0; i < 3; i++) { 
                //创建原生的连接，// com.mysql.jdbc.JDBC4Connection@8888
                Connection con = DriverManager.getConnection(url, "root",
                        "1234");
                //声明包装类
                MyConn conn = new MyConn(con); 
                pool.add(conn);//将包装类添加到池中去
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    //此方法来自于datasource,用于返回一个连接
    public Connection getConnection()  throws SQLException {
        synchronized (pool) {
            if (pool.size() == 0) {
                try {
                    pool.wait();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                return getConnection();
            }
            Connection con = pool.removeFirst();
            System.err.println("siize:" + pool.size());
            return con;
        }
    }

class MyConn implements Connection  {
        // 声明被包装类的成员
        private Connection conn;　//com.mysql.jdbc.Jdbc4Connection@1111

        // 通过构造接收MySql的connection的对象JDBC4Connection@8888
        public MyConn(Connection con) {
            this.conn = con;
        }
         //关闭连接
        public void close() throws SQLException {
            synchronized (pool) {
                //有人调用了关闭方法，不能关
                System.err.println("有人还连接了。。。。"+this);
                pool.add(this);
                pool.notify();
            }
        }
}

package cn.itcast.utils;
import java.io.IOException;
import java.lang.reflect.Method;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import javax.servlet.http.HttpServletResponse;
public class BaseServlet extends HttpServlet {
    @Override
    public void service(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        req.setCharacterEncoding("UTF-8");
        String methodName = req.getParameter("cmd");
        try{
            Method mm = this.getClass().getMethod(methodName,HttpServletRequest.class,HttpServletResponse.class);
            //声明包装类
            MyRequest mr = new MyRequest(req);
            mm.invoke(this,mr,resp);
        }catch(Exception e){
            e.printStackTrace();
        }
    }
}
//包装request
class MyRequest extends HttpServletRequestWrapper{
    private HttpServletRequest req;
    public MyRequest(HttpServletRequest request) {
        super(request);
        this.req=request;
    }
    //修改getparameter方法
    @Override
    public String getParameter(String name) {
        String value = req.getParameter(name);
        if(req.getMethod().equals("GET")){
            System.err.println("转码");
            try{
                value = new String(value.getBytes("ISO-8859-1"),"UTF-8");
            }catch(Exception e){
            }
        }
        return value;
    }
}