Servlet入门---张国亮--->总结心德之作业

 

1. 写出获取ServletContext的两种方式

package com.hbsi.context;

import java.io.IOException;

import javax.servlet.ServletContext;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class Context1 extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

//获取ServletContext方法1

ServletContext context1 = this.getServletConfig().getServletContext();

//获取ServletContext方法2

ServletContext context2 = this.getServletContext();

}

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

doGet(request, response);

}

}

2.使用ServletContext实现两个Servlet数据共享

package com.hbsi.context;

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class Context2 extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

//多个Servlet实现数据共享

String data="abcd";

this.getServletContext().setAttribute("data1", data);

}

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

doGet(request, response);

}

}

3.设置ServletContext初始化参数，然后对其之。

package com.hbsi.context;

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class Context3 extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

//配合Context2使用

String value = (String) this.getServletContext().getAttribute("data1");

System.out.println(value);

}

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

doGet(request, response);

}

}

4. 编写一个转发

package com.hbsi.context;

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class Context4 extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

System.out.println(this.getServletContext().getInitParameter("data"));

}

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

doGet(request, response);

}

}

5.通过ServletContext读取配置文件的内容。（使用两种方式）

package com.hbsi.context;

import java.io.IOException;

import javax.servlet.RequestDispatcher;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class Context5 extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

//实现转发

this.getServletContext().setAttribute("username","zhangsan");

RequestDispatcher rd = this.getServletContext().getRequestDispatcher("/index.jsp");

rd.forward(request, response);

}

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

doGet(request, response);

}

}

6.通过一般的java类读取配置文件的内容。

package com.hbsi.context;

import java.io.IOException;

import javax.servlet.RequestDispatcher;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class Context5 extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

//实现转发

this.getServletContext().setAttribute("username","zhangsan");

RequestDispatcher rd = this.getServletContext().getRequestDispatcher("/index.jsp");

rd.forward(request, response);

}

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

doGet(request, response);

}

}

package com.hbsi.context;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.io.InputStream;

import java.util.Properties;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import com.hbsi.dao.StudentDao;

public class Context6 extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

// 传统的方式错误了

/*

 * FileInputStream fis = new FileInputStream("src/db.properties");

 * 

 * Properties prop = new Properties(); prop.load(fis);

 * 

 * String driver = prop.getProperty("driver");

 * System.out.println(driver);

 */

StudentDao dao = new StudentDao();

dao.delete();

}

// 通过ServletContext读取配置文件 方法1

public void test1() throws IOException {

InputStream in = this.getServletContext().getResourceAsStream(

"/WEB-INF/classes/db.properties");

Properties prop = new Properties();

prop.load(in);

String driver = prop.getProperty("driver");

String url = prop.getProperty("url");

String username = prop.getProperty("username");

String password = prop.getProperty("password");

System.out.println(url);

}

// 通过ServletContext读取配置文件 方法2,获取了文件的绝对路径

public void test2() throws IOException {

String path = this.getServletContext().getRealPath(

"/WEB-INF/classes/db.properties");

int i = path.lastIndexOf("\\");

System.out.println(path.substring(i + 1));

FileInputStream fis = new FileInputStream(path);

Properties prop = new Properties();

prop.load(fis);

String driver = prop.getProperty("driver");

System.out.println(driver);

}

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

doGet(request, response);

}

}