cgb2110-day17

企业开发 2022-03-23 11:14:05 阅读次数: 0

文章目录

一,Request对象

–1,概述

1,用来接受请求,并且能够解析 请求参数.
GET方式: http://localhost:8080/user/userServlet?id=10&name=jack
POST方式: 数据不会在地址栏拼接的
2,常用的有两种:
ServletRequest 父接口
HttpServletRequest 子接口

–2,测试

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干一样的活
    }
    //http://localhost:8080/RequestServlet01?name=jack&pwd=123
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
    
        System.out.println("恭喜您,请求成功~~");
//      Servlet解析请求参数HttpServletRequest
        //1.getParameter()--根据参数名获取参数值
        String s = request.getParameter("name");
        String p = request.getParameter("pwd");
        System.out.println(s+p);
        //2.getParameterValues()--根据参数名获取参数值,可以获取多个值,存入数组
        String[] datas = request.getParameterValues("like");
        System.out.println( Arrays.toString(datas) );//[足球, 篮球]
        //3.HttpServletRequest的其他API
        System.out.println( request.getCharacterEncoding() );//获取请求使用的字符集UTF-8
        System.out.println( request.getMethod() );//获取请求方式GET
        System.out.println( request.getContextPath() );//获取项目名称(被缺省)
        System.out.println( request.getRequestURI() );//要访问的资源路径/RequestServlet01
        System.out.println( request.getRequestURL() );//包含着http://localhost:8080/RequestServlet01
        System.out.println( request.getRemotePort() );//发起请求时的端口号
        System.out.println( request.getQueryString() );//获取请求时携带的参数
    }
}

二,练习Request解析请求参数

–0,项目结构

在这里插入图片描述

–1,创建HTML网页

<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>测试 Servlet解析请求参数</title>
	</head>
	<body>
		<h1>1.以get方式提交的数据</h1>
		<form action="http://localhost:8080/user/addServlet">
			部门编号:<input type="number" name="deptno" placeholder="在这里输入部门编号.."/> <br />
			部门名称:<input type="text" name="deptname" placeholder="在这里输入部门名称.."/> <br />
			部门地址:<input type="text" name="deptloc" placeholder="在这里输入部门地址.."/> <br />
			<button type="submit">提交</button>
			<button type="reset">取消</button>
		</form>
		
		<h1>2.以post方式提交的数据</h1>
		<form method="post" action="http://localhost:8080/user/addServlet">
			账号:<input type="text" name="user" placeholder="在这里输入用户名.."/> <br />
			密码:<input type="password" name="pwd" placeholder="在这里输入密码.."/> <br />
			年龄:<input type="number" name="age" placeholder="在这里输入年龄.."/> <br />
			<button type="submit">提交</button>
			<button type="reset">取消</button>
		</form>
		
	</body>
</html>

–2,创建Servlet程序

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 {
    
    
    //处理那些post请求
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
    
        System.out.println("恭喜您,成功的提交了用户的数据!");
        //TODO 解析请求参数
        //TODO jdbc入库
    }
    //处理那些get请求
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
    
        System.out.println("恭喜您,成功的提交了部门的数据!");
        //TODO 解析请求参数
        //TODO jdbc入库
    }
}

三,改造Servlet程序实现入库

–1,导入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,需要指定坐标 。。。。。。。。。-->
        <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程序

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 {
    
    
    //处理那些post请求
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
    

        System.out.println("恭喜您,成功的提交了用户的数据!");
        //TODO 解析请求参数
        String user = request.getParameter("user");
        String pwd = request.getParameter("pwd");
        String age = request.getParameter("age");
        System.out.println(user+pwd+age);
        //TODO jdbc入库
        try {
    
    
            //1,导入jar包(在pom.xml里添加jar包的坐标依赖)
            //注册驱动
            Class.forName("com.mysql.jdbc.Driver");
            //获取连接
            String url="jdbc:mysql:///cgb211001?characterEncoding=utf8";
            Connection c = DriverManager.getConnection(url, "root", "root");
            //获取传输器
            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);
            //执行SQL
            ps.executeUpdate();//执行增删改的SQL
            //释放资源
            ps.close();
            c.close();
            System.out.println("恭喜您,用户信息已经入库成功!");
        } catch (Exception e) {
    
    
            e.printStackTrace();
        }
    }
    //处理那些get请求
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
    
        System.out.println("恭喜您,成功的提交了部门的数据!");
        //TODO 解析请求参数(部门编号,名称,地址)
        String deptno = request.getParameter("deptno");
        String deptname = request.getParameter("deptname");
        String deptloc = request.getParameter("deptloc");
        //TODO jdbc入库
        try {
    
    
            //1,导入jar包(在pom.xml里添加jar包的坐标依赖)
            //注册驱动
            Class.forName("com.mysql.jdbc.Driver");
            //获取连接
            String url="jdbc:mysql:///cgb211001?characterEncoding=utf8";
            Connection c = DriverManager.getConnection(url, "root", "root");
            //获取传输器
            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);
            //执行SQL
            ps.executeUpdate();
            //释放资源
            ps.close();
            c.close();
            System.out.println("恭喜您,部门信息已经入库成功!");
        } catch (Exception e) {
    
    
            e.printStackTrace();
        }
    }
}

–3,测试

在这里插入图片描述

四,请求转发

–1,概述

是服务器内部的过程,客户端感受不到.
过程: 浏览器 -> A----B
特点: 一次请求一次响应. 地址栏不会改变. 全程使用同一个Request对象.
实现: request.getRequestDispatcher(“B的访问规则”).forward(request,response);

–2,测试

在这里插入图片描述

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()被触发!");
        //请求转发: 实现  访问A时,A背后调用B 的效果
        //特点: 地址栏不变   +  同一个request对象(在A里存,在B里取)
        request.setAttribute("name","jack");
        //参数是  目标资源的访问规则.目标资源必须是在同一个项目里才能请求转发
        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()被触发!");
        //获取A中存好的数据
        Object o = request.getAttribute("name");
        System.out.println(o);//jack
    }
}

五,Response对象

–1,概述

专门用来给浏览器做出响应.
本质上就是获取一个输出流,利用输出流写出数据
常用对象:
ServletResponse – 父接口
HttpServletResponse – 子接口
常用方法:
1, getWriter() – 获取字符流(只能写出字符数据)
2, getOutputStream() – 获取字节流(写出任意格式的数据)
3, setContentType() – 写出数据中,如果包含中文,解决中文乱码
4, sendRedirect() – 完成重定向

–2,测试

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充当服务器:接受请求Request + 做出响应Response
// http://localhost:8080/resp/servlet01?id=10&name=张三
@WebServlet("/resp/servlet01")
public class ResponseServlet01 extends HttpServlet {
    
    
    //如果是get请求,Servlet会自动调用doGet()
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
    
        //TODO 解析请求参数
        String id = request.getParameter("id");
        String name = request.getParameter("name");

        //响应时使用的默认的字符集iso-8859-1,为了防止响应时的中文乱码问题,加以下代码
        response.setContentType("text/html;charset=utf8");
        //响应解析到的数据
        PrintWriter out = response.getWriter();
        out.println(id);//提供了一个换行写出的功能
        out.write(name);
    }
}

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