对象持久化是指将内存中的对象保存到可永久保存的存储设备中（如磁盘）的一种技术。
本文介绍的是除数据库之外的几种对象持久化方式。
具体如下：
- 保存成文本：即将内存对象以字节流的方式保存到文本中。
- 序列化成Xml:即将对象以Xml的格式存储。
- 序列化成Json:即将对象序列化成Json对象，然后存储。
- 序列化成二进制：即将对象序列化成二进制字节流保存到文件中。
涉及知识点：
- 序列化与反序列化
- 文件流的读写
- ListView显示复选框，并横向排列
如下图所示【主要功能是将用户输入的信息保存成各种格式，并从各个文档中进行读取出来】：
保存和读取文本文档代码如下：
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/// <summary> /// 保存成文本 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void btnSaveTxt_Click(object sender, EventArgs e) { Dictionary<string, string> dicInfos = GetDictionaryInfos(); string filePath = "objPerson.txt"; //采用using关键字，会自动释放 using (FileStream fs = new FileStream(filePath, FileMode.Create)) { using (StreamWriter sw = new StreamWriter(fs, Encoding.Default)) { foreach (var keyPair in dicInfos) { sw.WriteLine(string.Format("{0}={1}", keyPair.Key, keyPair.Value)); } } } } /// <summary> /// 从文本中读取 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void btnReadTxt_Click(object sender, EventArgs e) { string filePath = "objPerson.txt"; Dictionary<string, string> dic = new Dictionary<string, string>(); //采用using关键字，会自动释放 using (FileStream fs = new FileStream(filePath, FileMode.Open)) { using (StreamReader sw = new StreamReader(fs, Encoding.Default)) { while (!sw.EndOfStream) { string lineInfo = sw.ReadLine(); dic.Add(lineInfo.Split('=')[0], lineInfo.Split('=')[1]); } } } this.txtName.Text = dic["Name"]; this.dtBirthday.Text = dic["Birthday"]; if (dic["Gender"] == this.rbBoy.Text) { this.rbBoy.Checked = true; } else { this.rbGirl.Checked = true; } string[] loves = dic["Love"].Split('|'); foreach (var love in loves) { foreach (var item in this.lsvLove.Items) { ListViewItem li = item as ListViewItem; if (li.Text == love) { li.Checked = true; } } } } |
保存和读取Xml文档代码如下：
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/// <summary> /// 保存成Xml /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void btnSaveXml_Click(object sender, EventArgs e) { Person p = GetPersonInfos(); string filePath = "objPerson.xml"; using (FileStream fs = new FileStream(filePath, FileMode.Create)) { XmlSerializer serializer = new XmlSerializer(typeof(Person)); serializer.Serialize(fs, p); } } /// <summary> /// 从Xml中读取 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void btnReadXml_Click(object sender, EventArgs e) { string filePath = "objPerson.xml"; Person p; using (FileStream fs = new FileStream(filePath, FileMode.Open)) { XmlSerializer serializer = new XmlSerializer(typeof(Person)); object obj= serializer.Deserialize(fs); p = obj as Person; } SetPersonInfos(p); } |
保存和读取Json文档如下：
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/// <summary> /// 保存成Json /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void btnSaveJson_Click(object sender, EventArgs e) { Person p = GetPersonInfos(); JavaScriptSerializer jserializer = new JavaScriptSerializer(); string strJson = jserializer.Serialize(p); string strRegex = @"\\/Date\((\d+)\)\\/"; MatchEvaluator evaluator = new MatchEvaluator(ConvertJsonDateToDateString); //对时间进行处理，需要引用System.Text.RegularExpressions;命名空间 Regex reg = new Regex(strRegex); strJson = reg.Replace(strJson, evaluator); string filePath = "objPerson.json"; using (FileStream fs = new FileStream(filePath, FileMode.Create)) { using (StreamWriter sw = new StreamWriter(fs, Encoding.Default)) { sw.Write(strJson); } } } /// <summary> /// 从Json中读取 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void btnReadJson_Click(object sender, EventArgs e) { JavaScriptSerializer jserializer = new JavaScriptSerializer(); string filePath = "objPerson.json"; Person p; using (FileStream fs = new FileStream(filePath, FileMode.Open)) { using (StreamReader sw = new StreamReader(fs, Encoding.Default)) { string strJson = sw.ReadToEnd(); string strRegex = @"\d{4}-\d{2}-\d{2}\s\d{2}:\d{2}:\d{2}"; MatchEvaluator evaluator = new MatchEvaluator(ConvertDateStringToJsonDate); //对时间进行处理 Regex reg = new Regex(strRegex); strJson = reg.Replace(strJson, evaluator); p = jserializer.Deserialize<Person>(strJson); } } SetPersonInfos(p); } |
保存和读取Bin文档如下：
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/// <summary> /// 保存成二进制文件 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void btnSaveBin_Click(object sender, EventArgs e) { Person p = GetPersonInfos(); string filePath = "objPerson.bin"; using (FileStream fs = new FileStream(filePath, FileMode.Create)) { BinaryFormatter bf = new BinaryFormatter(); bf.Serialize(fs, p); } } /// <summary> /// 读取二进制文件 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void btnReadBin_Click(object sender, EventArgs e) { string filePath = "objPerson.bin"; Person p; using (FileStream fs = new FileStream(filePath, FileMode.Open)) { BinaryFormatter bf = new BinaryFormatter(); p= bf.Deserialize(fs) as Person; } SetPersonInfos(p); } |
备注：其实对象持久化和对象序列化是两个不同的概念。两者有关联却不同。
对象持久化：是使对象可以保存到实体存储介质中，在对象生命周期结束后可以再现。
对象序列化：是将对象或者数据结构转化成特定的格式，使其可在网络中传输，或者可存储在内存或者文件中。
以上就是本文的全部内容，希望本文的内容对大家的学习或者工作能带来一定的帮助，同时也希望多多支持服务器之家！
原文链接：http://www.cnblogs.com/hsiang/p/6392333.html
