JDBC工具类。。。
package it.cast.jdbcutils; import java.io.InputStream; 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.Properties; public class JdbcUtils { private static String JDriver=null; private static String connectDB=null; private static String username=null; private static String password=null; static { try { InputStream in =null; in= JdbcUtils.class.getClassLoader().getResourceAsStream("db.properties"); Properties prop=new Properties(); prop.load(in); JDriver=prop.getProperty("JDriver"); connectDB=prop.getProperty("connectDB"); username=prop.getProperty("username"); password=prop.getProperty("password"); Class.forName(JDriver); System.out.println("数据库连接成功"); } catch (Exception e) { throw new ExceptionInInitializerError("连接失败"); } } public static Connection getConnection() throws SQLException { return DriverManager.getConnection(connectDB,username,password); } public static void release (Connection conn,Statement st,ResultSet rs) { if(rs!=null) { try { rs.close(); } catch(Exception e) { e.printStackTrace(); } } if(st!=null) { try { st.close(); } catch(Exception e) { e.printStackTrace(); } } if(conn!=null) { try { conn.close(); } catch(Exception e) { e.printStackTrace(); } } System.out.println("数据库已经断开连接"); } //增删改方法。 public static void query(String sql,Object params []) throws SQLException { Connection conn =null; PreparedStatement st=null; ResultSet rs = null; conn = JdbcUtils.getConnection(); try { //获取数据连接 conn = JdbcUtils.getConnection(); //获取数据库对象并对SQL进行预编译 st =conn.prepareStatement(sql); //获取传进来的SQL,和传进来的参数。并进行赋值。 for(int i=0;i<params.length;i++) { st.setObject(i+1,params[i]); System.out.println(params[i]); } //执行 st.executeUpdate(); } finally { //释放 JdbcUtils.release(conn, st, rs); } } }
//实体类。
package in.cast.dao; public class data { private String date; private Integer num; public data (String date,Integer num) { this.date=date; this.num=num; } public String getDate() { return date; } public void setDate(String date) { this.date = date; } public int getNum() { return num; } public void setNum(Integer num) { this.num = num; } public String toString() { return date+" : "+num ; } }
测试:
package in.cast.dao; import it.cast.jdbcutils.JdbcUtils; import java.sql.Connection; import java.sql.ResultSet; import java.sql.Statement; import java.util.HashMap; import java.util.Iterator; import java.util.Map; import java.util.Set; public class JDBC_TEST { public static void main (String [] args) throws Exception { JDBC_TEST T=new JDBC_TEST(); HashMap<Integer,data> m=T.insert(); DataSearch(m); } public static void DataSearch(HashMap<Integer, data> m) { Set<Map.Entry<Integer,data>> entryset=m.entrySet(); Iterator <Map.Entry<Integer,data>>it=entryset.iterator(); while(it.hasNext()) { Map.Entry<Integer,data> mp=it.next(); System.out.println(mp.getKey()+" : "+mp.getValue()); } } public HashMap<Integer,data> insert() throws Exception { HashMap<Integer,data> mp = new HashMap<Integer,data>(); String s1; Integer s2; Connection conn=null; Statement st=null; ResultSet rs=null; Integer iCount=0; try { //获取数据库连接 conn=JdbcUtils.getConnection(); //返回一个statement,作用于发送SQL语句 。 st = conn.createStatement(); //SQL 语句 String sql=" select * from tt ; " ; //返回一个数据集 rs = st.executeQuery(sql) ; //update //循环 while(rs.next()) { iCount++; s1=rs.getString("日期");//等同getObject(column_name) s2=Integer.parseInt(rs.getString("存入")); mp.put(iCount,new data(s1,s2)); } } catch (Exception e) { e.printStackTrace(); } finally { JdbcUtils.release(conn,st, rs); } return mp; }
配置文件:
JDriver=com.microsoft.sqlserver.jdbc.SQLServerDriver connectDB=jdbc:sqlserver://127.0.0.1:1433;DatabaseName=test username=sa password=123
JDBC。
package in.cast.dao; import java.sql.*; public class test1{ public static void main(String[] args) { //com.microsoft.sqlserver.jdbc.SQLServerDriver 2008
String JDriver="com.microsoft.sqlserver.jdbc"; 2005 String connectDB="jdbc:sqlserver://127.0.0.1:1433;DatabaseName=test"; try{ Class.forName(JDriver);//通过反射加载驱动。 }catch(ClassNotFoundException e) { System.out.println("数据库连接异常"); //这里可以抛出一个自定义异常 } System.out.println("锟斤拷菘锟斤拷锟缴癸拷"); try{ String user="sa"; String password="123"; Connection con=DriverManager.getConnection(connectDB,user,password); Statement stmt=con.createStatement(); //建表 String query="create table TABLE1(ID NCHAR(2),NAME NCHAR(10))"; //提交语句 stmt.executeUpdate(query); String a1="INSERT INTO TABLE1 VALUES('1','a')"; String a2="INSERT INTO TABLE1 VALUES('2','b')"; String a3="INSERT INTO TABLE1 VALUES('3','c')"; stmt.executeUpdate(a1); stmt.executeUpdate(a2); stmt.executeUpdate(a3); ResultSet rs=stmt.executeQuery("SELECT * FROM TABLE1"); while(rs.next()){ System.out.println(rs.getString("ID")+" "+rs.getString("NAME")); } //从建表到插入数据到查询 。仅为熟悉语句。 stmt.close(); con.close(); }catch(SQLException e){ e.printStackTrace(); System.exit(0); } } }