Android序列化XML数据

private void backupToContact1(){
        StringBuilder sbuilder=new StringBuilder();
        // 设置XML的数据头
        sbuilder.append("");
        sbuilder.append("");
        // 遍历联系人信息
        for(Contact contact:Contacts){
            if(contact!=null){
                sbuilder.append("");
                sbuilder.append("");
                sbuilder.append(contact.getName());
                sbuilder.append("");

                sbuilder.append("");
                sbuilder.append(contact.getNumber());
                sbuilder.append("");

                sbuilder.append("

");
                sbuilder.append(contact.getAddress());
                sbuilder.append("

");

                sbuilder.append("");
            }
        }           
        sbuilder.append("");
        try {
            // 在SD卡上创建一个xml文件
            File file=new File(Environment.getExternalStorageDirectory(),"backup1.xml");
            FileOutputStream fos=new FileOutputStream(file);
            // 把序列化的数据写入到XML文件中
            fos.write(sbuilder.toString().getBytes());
            fos.close();
            Toast.makeText(MainActivity.this, "备份成功", 0).show();
        } catch (IOException e) {
            Toast.makeText(MainActivity.this, "备份失败", 0).show();
            e.printStackTrace();
        }
    }

private void backupToContact2(){
        try {
            // 在SD卡上创建一个文件
            File file=new File(Environment.getExternalStorageDirectory(),"backup2.xml");
            FileOutputStream fos=new FileOutputStream(file);
            // 获取一个XmlSerializer
            XmlSerializer serializer = Xml.newSerializer();
            // 设置XML的输出流以及编码格式
            serializer.setOutput(fos,"utf-8");
            // 设置文档的开头，以及编码格式
            serializer.startDocument("utf-8", true);

            // 开始标签
            serializer.startTag(null, "contacts");
            for(Contact contact:Contacts){
                serializer.startTag(null, "contact");
                // 设置contact标签的id属性
                serializer.attribute(null, "id", contact.getId()+"");
                serializer.startTag(null, "name");
                serializer.text(contact.getName());
                serializer.endTag(null, "name");

                serializer.startTag(null, "number");
                serializer.text(contact.getNumber());
                serializer.endTag(null, "number");

                serializer.startTag(null, "address");
                serializer.text(contact.getAddress());
                serializer.endTag(null, "address");
                serializer.endTag(null, "contact");
            }
            // 一个结束标签
            serializer.endTag(null, "contacts");
            // 标记文档的结束
            serializer.endDocument();
            // 关闭输出流
            fos.close();
            Toast.makeText(MainActivity.this, "备份成功", 0).show();
        } catch (Exception e) {
            e.printStackTrace();
            Toast.makeText(MainActivity.this, "备份失败", 0).show();
        }       
    }