cgb2110-day17-有解無憂

文章目錄

- 一,Request物件
- - --1,概述
  - --2,測驗
- 二,練習Request決議請求引數
- - --0,專案結構
  - --1,創建HTML網頁
  - --2,創建Servlet程式
- 三,改造Servlet程式實作入庫
- - --1,匯入jar包
  - --2,修改Servlet程式
  - --3,測驗
- 四,請求轉發
- - --1,概述
  - --2,測驗
- 五,Response物件
- - --1,概述
  - --2,測驗

一,Request物件

–1,概述

1,用來接受請求,并且能夠決議請求引數.
GET方式: http://localhost:8080/user/userServlet?id=10&name=jack
POST方式: 資料不會在地址欄拼接的
2,常用的有兩種:
ServletRequest 父介面
HttpServletRequest 子介面

–2,測驗

package cn.tedu.cgb2110boot03.request;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Arrays;

@WebServlet
public class RequestServlet01 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request, response);//和doGet干一樣的活
    }
    //http://localhost:8080/RequestServlet01?name=jack&pwd=123
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        System.out.println("恭喜您,請求成功~~");
//      Servlet決議請求引數HttpServletRequest
        //1.getParameter()--根據引數名獲取引數值
        String s = request.getParameter("name");
        String p = request.getParameter("pwd");
        System.out.println(s+p);
        //2.getParameterValues()--根據引數名獲取引數值,可以獲取多個值,存入陣列
        String[] datas = request.getParameterValues("like");
        System.out.println( Arrays.toString(datas) );//[足球, 籃球]
        //3.HttpServletRequest的其他API
        System.out.println( request.getCharacterEncoding() );//獲取請求使用的字符集UTF-8
        System.out.println( request.getMethod() );//獲取請求方式GET
        System.out.println( request.getContextPath() );//獲取專案名稱(被預設)
        System.out.println( request.getRequestURI() );//要訪問的資源路徑/RequestServlet01
        System.out.println( request.getRequestURL() );//包含著http://localhost:8080/RequestServlet01
        System.out.println( request.getRemotePort() );//發起請求時的埠號
        System.out.println( request.getQueryString() );//獲取請求時攜帶的引數
    }
}

二,練習Request決議請求引數

–0,專案結構

在這里插入圖片描述

–1,創建HTML網頁

<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>測驗 Servlet決議請求引數</title>
	</head>
	<body>
		<h1>1.以get方式提交的資料</h1>
		<form action="http://localhost:8080/user/addServlet">
			部門編號:<input type="number" name="deptno" placeholder="在這里輸入部門編號.."/> <br />
			部門名稱:<input type="text" name="deptname" placeholder="在這里輸入部門名稱.."/> <br />
			部門地址:<input type="text" name="deptloc" placeholder="在這里輸入部門地址.."/> <br />
			<button type="submit">提交</button>
			<button type="reset">取消</button>
		</form>
		
		<h1>2.以post方式提交的資料</h1>
		<form method="post" action="http://localhost:8080/user/addServlet">
			賬號:<input type="text" name="user" placeholder="在這里輸入用戶名.."/> <br />
			密碼:<input type="password" name="pwd" placeholder="在這里輸入密碼.."/> <br />
			年齡:<input type="number" name="age" placeholder="在這里輸入年齡.."/> <br />
			<button type="submit">提交</button>
			<button type="reset">取消</button>
		</form>
		
	</body>
</html>

–2,創建Servlet程式

package cn.tedu.cgb2110boot03.request;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
@WebServlet("/user/addServlet")
public class RequestServlet02 extends HttpServlet {
    //處理那些post請求
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        System.out.println("恭喜您,成功的提交了用戶的資料!");
        //TODO 決議請求引數
        //TODO jdbc入庫
    }
    //處理那些get請求
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        System.out.println("恭喜您,成功的提交了部門的資料!");
        //TODO 決議請求引數
        //TODO jdbc入庫
    }
}

三,改造Servlet程式實作入庫

–1,匯入jar包

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>cn.tedu</groupId>
    <artifactId>cgb2110boot03</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>cgb2110boot03</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <spring-boot.version>2.3.7.RELEASE</spring-boot.version>
    </properties>

    <dependencies>
        <!-- ，，，，，，，，，添加 jdbc的jar包,需要指定坐標 ，，，，，，，，，-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.48</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>${spring-boot.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>2.3.7.RELEASE</version>
                <configuration>
                    <mainClass>cn.tedu.cgb2110boot03.Cgb2110boot03Application</mainClass>
                </configuration>
                <executions>
                    <execution>
                        <id>repackage</id>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

</project>

–2,修改Servlet程式

package cn.tedu.cgb2110boot03.request;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

@WebServlet("/user/addServlet")
public class RequestServlet02 extends HttpServlet {
    //處理那些post請求
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        System.out.println("恭喜您,成功的提交了用戶的資料!");
        //TODO 決議請求引數
        String user = request.getParameter("user");
        String pwd = request.getParameter("pwd");
        String age = request.getParameter("age");
        System.out.println(user+pwd+age);
        //TODO jdbc入庫
        try {
            //1,匯入jar包(在pom.xml里添加jar包的坐標依賴)
            //注冊驅動
            Class.forName("com.mysql.jdbc.Driver");
            //獲取連接
            String url="jdbc:mysql:///cgb211001?characterEncoding=utf8";
            Connection c = DriverManager.getConnection(url, "root", "root");
            //獲取傳輸器
            String sql = "insert into user values(null,?,?,?)" ;//sql骨架
            PreparedStatement ps = c.prepareStatement(sql);
            ps.setObject(1,user);
            ps.setObject(2,pwd);
            ps.setObject(3,age);
            //執行SQL
            ps.executeUpdate();//執行增刪改的SQL
            //釋放資源
            ps.close();
            c.close();
            System.out.println("恭喜您,用戶資訊已經入庫成功!");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    //處理那些get請求
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        System.out.println("恭喜您,成功的提交了部門的資料!");
        //TODO 決議請求引數(部門編號,名稱,地址)
        String deptno = request.getParameter("deptno");
        String deptname = request.getParameter("deptname");
        String deptloc = request.getParameter("deptloc");
        //TODO jdbc入庫
        try {
            //1,匯入jar包(在pom.xml里添加jar包的坐標依賴)
            //注冊驅動
            Class.forName("com.mysql.jdbc.Driver");
            //獲取連接
            String url="jdbc:mysql:///cgb211001?characterEncoding=utf8";
            Connection c = DriverManager.getConnection(url, "root", "root");
            //獲取傳輸器
            String sql = "insert into dept values(?,?,?)" ;//sql骨架
            PreparedStatement ps = c.prepareStatement(sql);
            ps.setObject(1,deptno);
            ps.setObject(2,deptname);
            ps.setObject(3,deptloc);
            //執行SQL
            ps.executeUpdate();
            //釋放資源
            ps.close();
            c.close();
            System.out.println("恭喜您,部門資訊已經入庫成功!");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

–3,測驗

在這里插入圖片描述

四,請求轉發

–1,概述

是服務器內部的程序,客戶端感受不到.
程序: 瀏覽器 -> A----B
特點: 一次請求一次回應. 地址欄不會改變. 全程使用同一個Request物件.
實作: request.getRequestDispatcher(“B的訪問規則”).forward(request,response);

–2,測驗

在這里插入圖片描述

ServletA

package cn.tedu.cgb2110boot03.request;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebServlet("/testa")
public class ServletA extends HttpServlet {
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        System.out.println("ServletA...doGet()被觸發!");
        //請求轉發: 實作  訪問A時,A背后呼叫B 的效果
        //特點: 地址欄不變   +  同一個request物件(在A里存,在B里取)
        request.setAttribute("name","jack");
        //引數是  目標資源的訪問規則.目標資源必須是在同一個專案里才能請求轉發
        request.getRequestDispatcher("/testb").forward(request,response);
    }
}

ServletB

package cn.tedu.cgb2110boot03.request;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
@WebServlet("/testb")
public class ServletB extends HttpServlet {
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        System.out.println("ServletB...doGet()被觸發!");
        //獲取A中存好的資料
        Object o = request.getAttribute("name");
        System.out.println(o);//jack
    }
}

五,Response物件

–1,概述

專門用來給瀏覽器做出回應.
本質上就是獲取一個輸出流,利用輸出流寫出資料
常用物件:
ServletResponse – 父介面
HttpServletResponse – 子介面
常用方法:
1, getWriter() – 獲取字符流(只能寫出字符資料)
2, getOutputStream() – 獲取位元組流(寫出任意格式的資料)
3, setContentType() – 寫出資料中,如果包含中文,解決中文亂碼
4, sendRedirect() – 完成重定向

–2,測驗

package cn.tedu.cgb2110boot03.response;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;

//Servlet充當服務器:接受請求Request + 做出回應Response
// http://localhost:8080/resp/servlet01?id=10&name=張三
@WebServlet("/resp/servlet01")
public class ResponseServlet01 extends HttpServlet {
    //如果是get請求,Servlet會自動呼叫doGet()
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //TODO 決議請求引數
        String id = request.getParameter("id");
        String name = request.getParameter("name");

        //回應時使用的默認的字符集iso-8859-1,為了防止回應時的中文亂碼問題,加以下代碼
        response.setContentType("text/html;charset=utf8");
        //回應決議到的資料
        PrintWriter out = response.getWriter();
        out.println(id);//提供了一個換行寫出的功能
        out.write(name);
    }
}

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標籤：java

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