上传文件至 'src'

src/BarDao.java

@@ -0,0 +1,99 @@
+package com.dao;
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.ArrayList;
+import java.util.List;
+
+import com.entity.Bar;
+public class BarDao {
+	
+	 
+	
+
+	
+	  public ArrayList<Bar> query(){   //这里的query()方法是将从数据库中读取到的数据存储到集合中
+	   ResultSet rs = null;
+	   Statement st = null;
+	   ArrayList<Bar> barArr=new ArrayList<Bar>();
+		Connection conn = DataBaseUtils.getConnection();
+
+	  try{
+	       
+	  st = conn.createStatement();
+	  rs = st.executeQuery("select * from testbar");
+	   while(rs.next()){
+	    Bar bar=new Bar();
+	    bar.setName(rs.getString("name"));
+	    bar.setNum(rs.getInt("num"));
+	    barArr.add(bar);     //将从数据库中读取到的数据 以bar对象的方式存储到 集合中
+	   }
+	  }catch(SQLException e){
+	   e.printStackTrace();
+	  } 
+	  
+	  return barArr;   //返回该集合
+	  }
+	  
+		/**
+		 * 保存
+		 * @param var1
+		 */
+		public void save(String name,Integer num){
+			String sql = "insert into testbar(name,num) values(?,?)";
+			Connection conn = DataBaseUtils.getConnection();
+			try {
+				PreparedStatement pstmt = conn.prepareStatement(sql);
+				pstmt.setString(1, name);
+				pstmt.setInt(2, num);
+
+				pstmt.executeUpdate();
+			} catch (SQLException e) {
+				e.printStackTrace();
+			}
+		}
+			  
+	  
+	  
+	  
+	  public void update(String name,Integer num){          //该方法用于更新数据
+	   try{
+			Connection conn = DataBaseUtils.getConnection();
+
+	    PreparedStatement ptmt=conn.prepareStatement("update testbar set num=? where name=? ");
+	    ptmt.setInt(1, num);
+	    ptmt.setString(2,name);
+	    ptmt.execute(); 
+	  }catch(SQLException e){
+	   e.printStackTrace();
+	  }
+	   
+	  }
+
+
+
+
+
+
+
+
+/**
+ * 根据name删除
+ * @param name
+ */
+public void del(String name){
+	String sql = "delete from testbar where name=?";
+	Connection conn = DataBaseUtils.getConnection();
+	try {
+		PreparedStatement pstmt = conn.prepareStatement(sql);
+		pstmt.setString(1, name);
+		pstmt.executeUpdate();
+	} catch (SQLException e) {
+		e.printStackTrace();
+	}
+}}
+
+