JSP入门知识

1.传递表单参数:
String name = new String(request.getParameter("name"));

2.数据库连接:
~~MYSQL
//设置数据库的URL
String url =
"jdbc:mysql://localhost:3306/jspsky";
try
//加载驱动程序
Class.forname(
"org.gjt.mm.mysql.Driver").newInstance();
//建立连接
java.sql.Connection connection = java.sql.DriverManager.getConnection(url);
java.sql.Statement statement = connection.createStatement();
//SQL语句
String sqlStringi =
"insert into commu(name,tel,mobile,oicq,email)values(‘"+name+"’,‘"+tel+"’,‘"+mobile+"’,‘"+oicq+"’,‘"+email+"’)";
//运行SQL语句,并建立结果集
java.sql.ResultSet rsi = statement.executeQuery(sqlStringi);
//在屏
while(rss.next())
{
String a_name = rss.getString(1);
out.println(a_name);
{}
//关闭连接
connection.close();
}

//捕捉异常
catch(java.sql.SQLException e)

out.println(e.getMessage());
{}
catch(ClassNotFoundException e)

out.println(e.getMessage());
{}


~~DB2
//定义数据库的URL
String url =
"jdbc:db2:portal";
try

//加载驱动程序
Class.forName(
"COM.ibm.db2.jdbc.app.DB2Driver");
//建立连接,
java.sql.Connection connection = java.sql.DriverManager.getConnection(url,
"user","password");
java.sql.Statement statement = connection.createStatement();
//SQL语句
String sqlString =
"select * from client";
//执行SQL语句
java.sql.ResultSet rs = statement.executeQuery(sqlString);
//在屏幕上显示所连ze=2 color=blue>while(rs.next())
{
String name = rs.getString(1);
out.println(name);
{}
//关闭连接
connection.close();
}
//捕捉异常
catch(java.sql.SQLException e)

out.println(e.getMessage());
{}
catch(ClassNotFoundException e)

out.println(e.getMessage());
{}


3.文件操作

~~将一个字符串写到一个指定的文件中,如果该文件不存在,则新建一个文件,并完成写入;如果存在,则用此字符串覆盖原文件的所有内容
import java.io.*;
String str =
"print me 雪峰!";
//定义好打印的目标文件名

//取得当前主机存放WEB页面的绝对路径
String hostdir = System.getProperty(
"user.dir");
//取得当前主机所采用的路径分隔符
String fileBar = System.getProperty(
"file.separator");
//书写完整的目标文件存放路径
String nameOfFile=hostdir+fileBar+
"test.html";

try
//实例化一个文件输出流对象
FileOutputStream afile = new FileOutputStream(nameOfFile);
//将文件输出流,创建一个打印输出流对象
PrintWriter pw = new PrintWriter(afile);
pw.println(str);
//clean up
pw.close();
{}
catch(IOException e)
out.println(e.getMessage());
{}

~~列出指定目录下的文件列表
import java.io.*;
String cdur = System.getProperty(
"user.dir");
String fileBar = System.getProperty(
"file.separator");
String mydir =cdur+fileBar+
"doc"+fileBar+"jspsky";
File my = new File(mydir);
String d[] = my.list();
int i;
int l=d.length;
for(i=0;i out.print(d<i>);
{}


4.计数器
Integer count = null;
synchronized (application)
count =(Integer) application.getAttribute(
"d");
if (count ==null)
count =new Integer(
"0");
count = new Integer(count.intValue()+1);
application.setAttribute(
"d",count);
{}
out.println(count);
// 首先定义一个整形对象,并初始化为:NULL,
// 取回APPLICATION对像的属性D的值,并强制转化为整形对象,赋给COUNT
// 判断COUNT是否为空,为空时,将O赋给COUNT对象,
// 否则,通过COUNT。INTVALUE()方法,实现COUNT对象加1,并赋值给COUNT
// 最后,将COUNT对象保存在APPLICATION对象的D变量中。

lunzi   2005-03-17 00:43:53 评论:0   阅读:1616   引用:0

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