进行负载测试时servlet或服务器崩溃

Question

我写了一个servlet并在tomcat6上运行它。当有一个查询发送到指定的DNS时，servlet将获取信息并使用它们在数据库中搜索（mysql），然后写回一些东西。我在tomcat6中使用连接池。但是，当我尝试对我的程序进行负载测试时，我发现吞吐量非常低，并且很多例外情况如

Response code: Non HTTP response code:
java.net.SocketTimeoutException Non HTTP response message: Read timed
out
  Your result:
  Team and Account info\n   at java.net.SocketInputStream.socketRead0(Native Method);   at
java.net.SocketInputStream.read(SocketInputStream.java:152);    at
java.net.SocketInputStream.read(SocketInputStream.java:122);    at
org.apache.http.impl.io.AbstractSessionInputBuffer.fillBuffer(AbstractSessionInputBuffer.java:166); at
org.apache.http.impl.io.SocketInputBuffer.fillBuffer(SocketInputBuffer.java:90);    at
org.apache.http.impl.io.AbstractSessionInputBuffer.readLine(AbstractSessionInputBuffer.java:281);   at
org.apache.http.impl.conn.DefaultHttpResponseParser.parseHead(DefaultHttpResponseParser.java:92);   at
org.apache.http.impl.conn.DefaultHttpResponseParser.parseHead(DefaultHttpResponseParser.java:61);   at
org.apache.http.impl.io.AbstractMessageParser.parse(AbstractMessageParser.java:254);    at
org.apache.http.impl.AbstractHttpClientConnection.receiveResponseHeader(AbstractHttpClientConnection.java:289); at
org.apache.http.impl.conn.DefaultClientConnection.receiveResponseHeader(DefaultClientConnection.java:252);  at
org.apache.http.impl.conn.ManagedClientConnectionImpl.receiveResponseHeader(ManagedClientConnectionImpl.java:191);  at
org.apache.http.protocol.HttpRequestExecutor.doReceiveResponse(HttpRequestExecutor.java:300);   at
org.apache.http.protocol.HttpRequestExecutor.execute(HttpRequestExecutor.java:127); at
org.apache.http.impl.client.DefaultRequestDirector.tryExecute(DefaultRequestDirector.java:715); at
org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:520);    at
org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:906);    at
org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:805);    at
org.apache.jmeter.protocol.http.sampler.HTTPHC4Impl.executeRequest(HTTPHC4Impl.java:475);   at
org.apache.jmeter.protocol.http.sampler.HTTPHC4Impl.sample(HTTPHC4Impl.java:295);   at
org.apache.jmeter.protocol.http.sampler.HTTPSamplerProxy.sample(HTTPSamplerProxy.java:74);  at
org.apache.jmeter.protocol.http.sampler.HTTPSamplerBase.sample(HTTPSamplerBase.java:1105);  at
org.apache.jmeter.protocol.http.sampler.HTTPSamplerBase.sample(HTTPSamplerBase.java:1094);  at
org.apache.jmeter.threads.JMeterThread.process_sampler(JMeterThread.java:429);  at
org.apache.jmeter.threads.JMeterThread.run(JMeterThread.java:257);  at
java.lang.Thread.run(Thread.java:745)

有人可以给我一些建议吗？这是我的servlet代码，这是我在这个web项目中使用的唯一Java代码，谢谢

@SuppressWarnings("serial")
public class Servlet extends HttpServlet {

    @Override
    public void doGet(final HttpServletRequest req, final HttpServletResponse res) throws IOException {
        Connection conn = null;
        DataSource ds = null;
        InitialContext ctx;
        try {
            ctx = new InitialContext();
            ds = (DataSource) ctx.lookup("java:comp/env/jdbc/mysql");
            conn = ds.getConnection();
            final Statement stmt = conn.createStatement();
            stmt.executeQuery("SET NAMES 'utf8mb4'; ");
        } catch (final SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        res.setContentType("text/plain;charset=UTF-8");
        final PrintWriter pw = res.getWriter();

        try {
            final Statement stmt = conn.createStatement();
            String teamInfo = "aa\n";
            ResultSet rs = null;
            final String info = req.getQueryString();
            final String[] sp = info.split("&");
            final String[] child0 = sp[0].split("=");
            final String[] child1 = sp[1].split("=");
            final String sqlString = "select * from tweets where timeandid=\"" + child1[1] + child0[1] + "\"";
            rs = stmt.executeQuery(sqlString);
            rs.next();
            final String a = rs.getString(2);
            teamInfo = teamInfo + rs.getString(3) + ":" + rs.getString(4).trim() + ":" + a + "\n";
            pw.print(teamInfo);
            pw.flush();

            rs.close();
            stmt.close();
        } catch (final SQLException ex) {
            System.out.println(ex);

        } finally {
            System.out.println("over");
        }
        pw.close();
        try {
            conn.close();
        } catch (final SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}