JavaWeb-Servlet--day01（笔记）

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传智播客-JavaWEB核心编程视频教程

    <!-- 配置和映射Servlet -->
    <servlet>
        <!-- Servlet的注册名 -->
        <servlet-name>MyServlet</servlet-name>
        <!-- Servlet的全类名 -->
        <servlet-class>pack_Servlet.MyServlet</servlet-class>

        <!-- 可以指定Servlet被创建的时机 -->
        <load-on-startup>5</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>MyServlet</servlet-name>
        <url-pattern>/index</url-pattern>
    </servlet-mapping>

XML文件内容

<servlet>
    <servlet-name>MyServlet</servlet-name>
    <servlet-class>pack_Servlet.MyServlet</servlet-class>
    <！--配置初始数据-->
    <init-param>
        <param-name>name</param-name>
        <param-value>Micheal</param-value>
    </init-param>
    <init-param>
        <param-name>password</param-name>
        <param-value>123@asd</param-value>
    </init-param>

    <load-on-startup>5</load-on-startup>
</servlet>

<servlet-mapping>
    <servlet-name>MyServlet</servlet-name>
    <url-pattern>/index</url-pattern>
</servlet-mapping>

Servlet编写内容

public void init(ServletConfig servletConfig) throws ServletException {
        System.out.println("init()...");
        String user=servletConfig.getInitParameter("name");
        System.out.println("user"+user);

        Enumeration<String> names=servletConfig.getInitParameterNames();
        while(names.hasMoreElements()) {
            String name=names.nextElement();
            String value=servletConfig.getInitParameter(name);
            System.out.println("name:"+name+": Values:"+value);
        }
        System.out.println(servletConfig.getServletName());
    }

输出结果：

XML代码

<context-param>
    <param-name>address</param-name>
    <param-value>NanJing</param-value>
</context-param>
<context-param>
    <param-name>age</param-name>
    <param-value>23</param-value>
</context-param>

Servlet代码：

ServletContext servletContext=servletConfig.getServletContext();
String address=servletContext.getInitParameter("address");
System.out.println("Address:"+address);

Enumeration<String> elements=servletContext.getInitParameterNames();
while(elements.hasMoreElements()) {
    String name=elements.nextElement();
    String value=servletContext.getInitParameter(name);
    System.out.println("name:"+name+";value:"+value);
}

Servlet代码：

    //只能查找WEB-INF目录内的文件路径，该路径指的是发布在服务器内的绝对路径
    String path=servletContext.getRealPath("/web.xml");
    System.out.println("Path"+path);

try {
    ClassLoader classLoader=getClass().getClassLoader();
    InputStream is=classLoader.getResourceAsStream("Mytest.properties");
    System.out.println("1:"+is);
} catch (Exception e) {
    e.printStackTrace();
}

try {
    InputStream is2=servletContext.getResourceAsStream("Mytest.properties");//null,因为目录不对
    System.out.println("2:"+is2);
    InputStream is3=servletContext.getResourceAsStream("/WEB-INF/classes/Mytest.properties");
    System.out.println("3:"+is3);
} catch (Exception e) {
    e.printStackTrace();
}

输出结果

PathE:\Experiment\Java\eclipse-workspace.metadata.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\day_01\web.xml
1:java.io.BufferedInputStream@7b1e7f1e
2:null
3:java.io.FileInputStream@7f721d79

JSP界面：

<form action="/WebApplication2/NewServlet" method="post">
    Name:<input type="text" placeholder="Pelase enter name" name="name"/>
    Password:<input type="text"  placeholder="Please your password" name="password"/>
    <br/><br/>
    Hobby:
    <input type="checkbox" name="hobby" value="Music">Music
    <input type="checkbox" name="hobby" value="Sprot">Sport
    <input type="checkbox" name="hobby" value="Reading">Reading
    <input type="checkbox" name="hobby" value="Game">Game
    <br/>
    <input type="submit"  style="submit" class="login_btn" value="submit" />
</form>

Servlet界面

System.err.println("请求来了！！！");
System.err.println("request" + request);
//获取单个参数值
String name = request.getParameter("name");
String password = request.getParameter("password");
System.err.println("name:" + name + ";password:" + password);
//获取参数组
String hobby = request.getParameter("hobby");
System.err.println("hobby:" + hobby);
String[] hobbys = request.getParameterValues("hobby");
for (String element : hobbys) {
    System.err.print("-->" + element);
}

//获取传过来的参数：getParameterNames（）和getParameter（）
//方法一:
Enumeration<String> names=request.getParameterNames();
while(names.hasMoreElements()){
    String param_name=names.nextElement();
    String param_values=request.getParameter(param_name);//注：若是checkbox，只能获取到首个参数
    System.err.print("^^param_name:" + param_name+";param_values"+param_values);           
}
//方法二
Map<String,String[]> map=request.getParameterMap();
for(Map.Entry<String,String[]> entry:map.entrySet()) {
    System.err.print("**param_name:" + entry.getKey()+";param_values"+Arrays.asList(entry.getValue()));
}

Servlet代码：

HttpServletRequest httpServletRequest = (HttpServletRequest) request;

String requestURI = httpServletRequest.getRequestURI();//获取地址
System.err.println(requestURI);

String method = httpServletRequest.getMethod();//获取请求方式
System.err.println(method);

String queryString = httpServletRequest.getQueryString();//前提：GET请求，POST请求为NULL；获取地址栏中？后面的数据
System.err.println(queryString);

String servletPath = httpServletRequest.getServletPath();//获取当前Servlet的名称
System.err.println(servletPath);

//response.setContentType("text/html;charset=UTF-8");//默认的相应类型为html格式类型

response.setContentType("application/msword");//设置相应的类型为Word类型;

PrintWriter out = response.getWriter();//getWriter()方法
String name = request.getParameter("name");
out.println("Name:" + name);