android.os.NetworkOnMainThreadException

                          有几个细节性的问题是，

                                第一， 一般原有通信的代码都是共通的API， 被许多个Activity调用， 一个良好的修改方法是在共通API里面new AyncTask

                               第二， 通信的API一般来说都是同步的， 你通信，然后画面主线程需要堵塞住，等待API的通信结果，再决定下面的业务逻辑的走向。

所以，这块可以采取 AyncTask.get()， 让主线程堵塞，直到通信结束。 当然，如果你需要将通信异步的话， 可以用Handler机制来解决


具体调用代码如下：HTTP异

步请求

package com.qqtech.ucstar.utils;

import java.io.File;
import java.io.IOException;
import java.nio.charset.Charset;

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.mime.HttpMultipartMode;
import org.apache.http.entity.mime.MultipartEntity;
import org.apache.http.entity.mime.content.FileBody;
import org.apache.http.impl.client.DefaultHttpClient;

import android.os.AsyncTask;

public class HttpReqTask extends AsyncTask<Object, Object, HttpResponse> {

@Override
protected HttpResponse doInBackground(Object arg0) {
String fileUploadUrl = (String) arg0[0];
String streamid = (String) arg0[1];
File file = (File) arg0[2];
//boolean paramBoolean = Boolean.parseBoolean((String) arg0[3]);
//String paramString3 = (String) arg0[4];
HttpClient localHttpClient = new DefaultHttpClient();
//String str1 = "fileName";
File localFile = file;
try {
if ((localFile == null) || (!localFile.exists()))
throw new IOException("文件不存在:" + localFile);
} catch (IOException e1) {
e1.printStackTrace();
}
HttpPost localPostMethod = new HttpPost(fileUploadUrl+"?streamid="+streamid+"&fileencode=UTF-8");
//MultipartEntity reqEntity = new MultipartEntity(HttpMultipartMode.BROWSER_COMPATIBLE);
MultipartEntity reqEntity = new MultipartEntity(HttpMultipartMode.BROWSER_COMPATIBLE,null, Charset.forName("UTF-8"));
try {
FileBody bin = new FileBody(file);
reqEntity.addPart("file", bin);
localPostMethod.setEntity(reqEntity);
HttpResponse response = localHttpClient.execute(localPostMethod);
return response;
} catch (Exception e) {
e.printStackTrace();
}
return null;
}

}

jdbc:oracle:thin:@(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=vip1)(PORT

=1521))(ADDRESS=(PROTOCOL=TCP)(HOST=vip2)(PORT=1521))(LOAD_BALANCE=yes)(FAILOVER=

on))(CONNECT_DATA=(SERVICE_NAME=gs)))

测试截图：exp ZM/sql123@ORCL owner=ZM file=F\abcd.dmp

导入命令：imp 用户名/密码@数据库 fromuser=用户名 touser=用户名 file=d:\cu.dmp ignore=y

 imp:命令类型  

cu/mycu@db:导入的数据库登陆(用户名/密码@数据库)  

fromuser:文件的指定用户

 touser：指定导入到当前登录的数据库某个用户  

file:需要导入的数据文件  

ignore:是否忽略创建错误

测试截图：

imp ZM/sql123@ORCL fromuser=ZM touser=SZZM file=F:\test.dmp ignore=y

问题一：RMI服务提供程序运行在Windows操作系统下，RMI服务可以正常访问，但将RMI服务提供程序部署到Linux操作系统下后，RMI服务无法访问，提示

org.springframework.remoting.RemoteConnectFailureException:

Cannot connect to remote service [rmi://192.168.0.106:1199/ItemRetag]; nested exception is java.rmi.ConnectException: Connection refused to host: 127.0.0.1; ……   
 解决办法：在加载RMI服务之前将当前服务器的IP指定给hostName，如 System.setProperty("java.rmi.server.hostname", "192.168.100.7");或者修改/etc/hosts文件，在这个文件中加 192.168.100.54  testlinux1 localhost.localdomain localhost 就行，或者将/etc/hosts文件中默认的127.0.0.1改成当前机器的IP即可！

问题二：java.rmi.server.ExportException: internal error: ObjID already in use Caused by: java.rmi.server.ExportException: internal error: ObjID already in use……

出现这种问题及有可能是/etc/hosts文件中指定的IP并不是当前服务器的真实IP，RMI在初始化时注册服务失败。

通过System.out.println(InetAddress.getLocalHost().toString());查看当前主机的IP是否为真实IP，如显示为SIMBANK/220.250.64.24，而真实IP为192.168.1.2         

解决办法：修改/etc/hosts文件中错误的IP即可，将：

220.250.64.24          SIMBANK
修改为

192.168.1.2          SIMBANK

private void batchParseGroup(){
        Connection con= null;
        PreparedStatement ps =null;
        try {
            con= DbConnectionManager.getConnection();
            con.setAutoCommit(false);
            String sql = " insert into jivegroup(uri,groupname,pgroupid,description,creationdate,modificationdate,priority,selfpriority) values(?,?,?,?,?,?,?,?)";
            ps= con.prepareStatement(sql);
            for(int i=0;i<groupList.size();i++){
                Group group = groupList.get(i);
                ps.setString(1, group.getUri());
                ps.setString(2, group.getName());
                ps.setString(3, group.getPgroupId());
                ps.setString(4, group.getName());
                ps.setString(5, ""+System.currentTimeMillis());
                ps.setString(6, ""+System.currentTimeMillis());
                ps.setInt(7, group.getPriority());
                ps.setInt(8, group.getPriority());
                ps.addBatch();
                if(i%100==0){
                    ps.executeBatch();
                }
            }
            con.commit();
            ps.executeBatch();
        } catch (SQLException e) {
            e.printStackTrace();
        }finally{
            DbConnectionManager.closeConnection(ps, con);
        }
    }

关于rewriteBatchedStatements参数，Mysql官方的说明：

Should the driver use multiqueries (irregardless of the setting of "allowMultiQueries") as well as rewriting of prepared statements for INSERT into multi-value inserts when executeBatch() is called? Notice that this has the potential for SQL injection if using plain java.sql.Statements and your code doesn't sanitize input correctly. Notice that for prepared statements, server-side prepared statements can not currently take advantage of this rewrite option, and that if you don't specify stream lengths when using PreparedStatement.set*Stream(), the driver won't be able to determine the optimum number of parameters per batch and you might receive an error from the driver that the resultant packet is too large. Statement.getGeneratedKeys() for these rewritten statements only works when the entire batch includes INSERT statements.