Java簡略單純盤算器法式設計。本站提示廣大學習愛好者：（Java簡略單純盤算器法式設計）文章只能為提供參考，不一定能成為您想要的結果。以下是Java簡略單純盤算器法式設計正文
本文引見了C#中csv文件與DataTable相互導入處置實例解析，重要功效代碼封裝處置下，絕對比擬簡略。今後項目用到的話可以直接應用。詳細辦法以下：
1.封裝好的類以下：
using System;
using System.Data;
using System.IO;
using System.Text;
using CSharpUtilHelpV2;
using StringUtilHelp;
namespace DBUtilHelpV2Plus
{
public static class DBToolV2Plus
{
/// <summary>
/// 將DataTable導出到CSV.
/// </summary>
/// <param name="table">DataTable</param>
/// <param name="fullSavePath">保留途徑</param>
/// <param name="tableheader">題目信息</param>
/// <param name="columname">列稱號『eg:姓名,年紀』</param>
/// <returns>導出勝利true;導出掉敗false</returns>
public static bool ToCSV(this DataTable table, string fullSavePath, string tableheader, string columname)
{
ArgumentChecked(table, fullSavePath);
//------------------------------------------------------------------------------------
try
{
string _bufferLine = "";
using (StreamWriter _writerObj = new StreamWriter(fullSavePath, false, Encoding.UTF8))
{
if (!string.IsNullOrEmpty(tableheader))
_writerObj.WriteLine(tableheader);
if (!string.IsNullOrEmpty(columname))
_writerObj.WriteLine(columname);
for (int i = 0; i < table.Rows.Count; i++)
{
_bufferLine = "";
for (int j = 0; j < table.Columns.Count; j++)
{
if (j > 0)
_bufferLine += ",";
_bufferLine += table.Rows[i][j].ToString();
}
_writerObj.WriteLine(_bufferLine);
}
return true;
}
}
catch (Exception)
{
return false;
}
}
/// <summary>
/// 參數檢討
/// </summary>
/// <param name="table"></param>
/// <param name="fullSavePath"></param>
private static void ArgumentChecked(DataTable table, string fullSavePath)
{
if (table == null)
throw new ArgumentNullException("table");
if (string.IsNullOrEmpty(fullSavePath))
throw new ArgumentNullException("fullSavePath");
string _fileName = CSharpToolV2.GetFileNameOnly(fullSavePath);
if (string.IsNullOrEmpty(_fileName))
throw new ArgumentException(string.Format("參數fullSavePath的值{0},不是准確的文件途徑!", fullSavePath));
if (!_fileName.InvalidFileNameChars())
throw new ArgumentException(string.Format("參數fullSavePath的值{0},包括不法字符!", fullSavePath));
}
/// <summary>
/// 將CSV文件數據導入到Datable中
/// </summary>
/// <param name="table"></param>
/// <param name="filePath">DataTable</param>
/// <param name="rowIndex">保留途徑</param>
/// <returns>Datable</returns>
public static DataTable AppendCSVRecord(this DataTable table, string filePath, int rowIndex)
{
ArgumentChecked(table, filePath);
if (rowIndex < 0)
throw new ArgumentException("rowIndex");
using (StreamReader reader = new StreamReader(filePath, Encoding.UTF8, false))
{
int i = 0, j = 0;
reader.Peek();
while (reader.Peek() > 0)
{
j = j + 1;
string _line = reader.ReadLine();
if (j >= rowIndex + 1)
{
string[] _split = _line.Split(',');
DataRow _row = table.NewRow();
for (i = 0; i < _split.Length; i++)
{
_row[i] = _split[i];
}
table.Rows.Add(_row);
}
}
return table;
}
}
}
}
2.代碼應用測試以下：
using System;
using System.Data;
using DBUtilHelpV2;
using DBUtilHelpV2Plus;
namespace DBUtilHelpV2PlusTest
{
class Program
{
static DataTable testDb = null;
static string fullSavePath = string.Format(@"C:\{0}.csv", DateTime.Now.ToString("yyyyMMddHH"));
static void Main(string[] args)
{
try
{
CreateTestDb();
Console.WriteLine(string.Format("DataTable導出到CSV文件{0}.", testDb.ToCSV(fullSavePath, "姓名,年紀", "人員信息表") == true ? "勝利" : "掉敗"));
testDb.Rows.Clear();
Console.WriteLine(string.Format("清空數據,以後{0}條數據.", testDb.Rows.Count));
testDb = testDb.AppendCSVRecord(fullSavePath, 2);
Console.WriteLine(string.Format("CSV文件導入到Datable,導入{0}條數據.", testDb.Rows.Count));
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
finally
{
Console.ReadLine();
}
}
static void CreateTestDb()
{
if (testDb == null)
{
testDb = DBToolV2.CreateTable("Name,Age|int");
for (int i = 1; i <= 10; i++)
{
DataRow _row = testDb.NewRow();
_row["Name"] = string.Format("YanZhiwei_{0}", i);
_row["Age"] = i;
testDb.Rows.Add(_row);
}
}
}
}
}
運轉後果以下圖所示：
h(z) { case 0: t1.setText(""+(x+y)); t1.setHorizontalAlignment(JTextField.RIGHT);break; case 1: t1.setText(""+(x-y)); t1.setHorizontalAlignment(JTextField.RIGHT);break; case 2: t1.setText(""+(x*y)); t1.setHorizontalAlignment(JTextField.RIGHT);break; case 3: t1.setText(""+(x/y)); t1.setHorizontalAlignment(JTextField.RIGHT);break; } } else if(e.getSource()==b[11])//單擊"."按鈕輸出小數 { if(t1.getText().trim().indexOf('.')!=-1)//斷定字符串中能否曾經包括了小數點 { } else //假如沒有小數點 { if(t1.getText().trim().equals("0"))//假如初時顯示為0 { t1.setText(str.append(e.getActionCommand()).toString()); t1.setHorizontalAlignment(JTextField.RIGHT); } else if(t1.getText().trim().equals(""))//假如初時顯示為空則不做任何操作 {} else { t1.setText(str.append(e.getActionCommand()).toString()); t1.setHorizontalAlignment(JTextField.RIGHT); } } y=0d; } else if(e.getSource()==b6) //求平方根 { x=Double.parseDouble(t1.getText().trim()); if(x<0) { t1.setText("數字格局異常"); t1.setHorizontalAlignment(JTextField.RIGHT); } else { t1.setText(""+Math.sqrt(x)); t1.setHorizontalAlignment(JTextField.RIGHT); } str.setLength(0); y=0d; } else { if(e.getSource()==b[0])//假如選擇的是"0"這個數字鍵 { if(t1.getText().trim().equals("0"))//假如顯示屏顯示的為零不做操作 {} else t1.setText(str.append(e.getActionCommand()).toString()); t1.setHorizontalAlignment(JTextField.RIGHT); y=Double.parseDouble(t1.getText().trim()); } else if (e.getSource()==b2) //選擇的是back鍵 { if(!t1.getText().trim().equals("0"))//假如顯示屏顯示的不是零 { if(str.length()!=1) { t1.setText(str.delete(str.length()-1,str.length()).toString());//能夠拋出字符串越界異常 t1.setHorizontalAlignment(JTextField.RIGHT); } else { t1.setText("0"); t1.setHorizontalAlignment(JTextField.RIGHT); str.setLength(0); } } y=Double.parseDouble(t1.getText().trim()); } else { t1.setText(str.append(e.getActionCommand()).toString()); t1.setHorizontalAlignment(JTextField.RIGHT); y=Double.parseDouble(t1.getText().trim()); } } } catch(NumberFormatException e1){ t1.setText("數字格局異常"); t1.setHorizontalAlignment(JTextField.RIGHT); } catch(StringIndexOutOfBoundsException e1){t1.setText("字符串索引越界"); t1.setHorizontalAlignment(JTextField.RIGHT);} } }運轉後果圖：
一個Java簡略單純盤算器法式設計就這麼完成了，願望本文可以對年夜家編寫盤算器有所啟示，這只是一個簡略單純的盤算器，年夜家還可以持續施展，完美盤算器的功效。
