ios用form提交表单 form表单提交servlet

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goody 2023-11-09 10:03:40

文章标签 ios用form提交表单 servlet 乱码 java bc 文章分类 iOS 移动开发

servlet提交表单

post请求

特点
读取提交的请求参数值

request提供的getParameter
request提供的getParameterValues

form表单提交数据

表单中文参数乱码

原因：
解决

表单提交方式为post
表单提交方式为get

写一个Servlet,将所有员工信息以表格形式展现出来

maven项目的jar包依赖
数据库
实体类
数据库连接配置
数据库连接工具类
数据库访问类
addEmp.html
新增servlet
列表servlet
测试

post请求

表单的method=“post”，浏览器会发送post请求

特点

不会将请求参数显示在浏览器地址栏，相对安全
并不会对请求参数加密
会将请求参数添加到实体内容里面，所以，可以提交大量数据给服务器

读取提交的请求参数值

request提供的getParameter

//如果请求参数名写错，会返回null值。
//如果不填写任何数据，会获得空字符串
String  getParameter(String paramName);

request提供的getParameterValues

//当有多个请求参数名相同时，用该方法
//多选框，如果不选择任何选项，浏览器不会发送任何数据给服务器。
String[] getParameterValues(String paramName);

form表单提交数据

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>计算BMI指数</title>
</head>
<body style="font-size:30px;">
	<form action="bmi" method="post">
		<fieldset>
			<legend>计算BMI指数</legend>
			身高（米）：<input name="height"><br>
			体重（公斤）：<input name="weight"><br>
			<!--checkbox:复选框  -->
			兴趣：钓鱼<input name="interest" type="checkbox" value="钓鱼">
			做饭<input name="interest" type="checkbox" value="做饭">
			台球<input name="interest" type="checkbox" value="台球"><br>
			城市：<input name="city"><br>
			<input type="submit" value="确定">
		</fieldset>
	</form>
</body>
</html>

package web;

import java.io.IOException;

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

@WebServlet("/bmi")
public class BmiServlet extends HttpServlet {
	public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		request.setCharacterEncoding("UTF-8");
		response.setContentType("text/html;charset=utf-8");
		response.setCharacterEncoding("UTF-8");
		// 身高
		String height = request.getParameter("height");
		// 体重
		String weight = request.getParameter("weight");
		// 兴趣
		String[] interest = request.getParameterValues("interest");
		response.getWriter().print("兴趣：");
		for (String str : interest) {
			response.getWriter().print(str + " ");
		}
		// 城市
		String city = request.getParameter("city");
		response.getWriter().println("城市：" + city);
		/*
		 *bmi指数: 体重千克数除以身高米数的平方
		 */
		double bmi = Double.parseDouble(weight) / Double.parseDouble(height) / Double.parseDouble(height);
		String status = "正常";
		if (bmi < 18.5) {
			status = "过轻";
		}
		if (bmi > 25) {
			status = "过重";
		}
		response.getWriter().println("<h3>您的bmi指数为：" + bmi + "</h3>" + "<h3>您的身体状况:" + status + "</h3>");
	}
}

测试
http://localhost:8087/servlet/form.html ios用form提交表单 form表单提交servlet_bc
ios用form提交表单 form表单提交servlet_servlet_02

表单中文参数乱码

原因：

表单提交时，浏览器会对中文参数值进行编码。服务器端
默认会使用iso-8859-1来解码
会使用表单所在的页面打开时使用的字符集来编码

解决

表单提交方式为post

//要加到所有的request.getParameter方法前面
request.setCharacterEncoding("utf-8");

表单提交方式为get

ios用form提交表单 form表单提交servlet_java_03

设置（在tomcat下的conf文件下的server.xml中添加）
注：只针对get请求有效

写一个Servlet,将所有员工信息以表格形式展现出来

maven项目的jar包依赖

<!--添加tomcat插件 -->
	<build>
		<plugins>
			<plugin>
				<groupId>org.apache.tomcat.maven</groupId>
				<artifactId>tomcat7-maven-plugin</artifactId>
				<version>2.2</version>
				<configuration>
					<port>8087</port>
					<hostName>localhost</hostName>
					<uriEncoding>UTF-8</uriEncoding>
				</configuration>
			</plugin>
		</plugins>
	</build>
	<dependencies>
		<!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
		<dependency>
			<groupId>javax.servlet</groupId>
			<artifactId>javax.servlet-api</artifactId>
			<version>4.0.1</version>
			<scope>provided</scope>
		</dependency>
		<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
			<version>5.1.40</version>
		</dependency>
		<dependency>
			<groupId>commons-dbcp</groupId>
			<artifactId>commons-dbcp</artifactId>
			<version>1.4</version>
		</dependency>
		<dependency>
			<groupId>junit</groupId>
			<artifactId>junit</artifactId>
			<version>4.12</version>
			<scope>test</scope>
		</dependency>
	</dependencies>

数据库

create database ems;
use ems;
CREATE TABLE `t_emp` (
  `id` int(11) NOT NULL AUTO_INCREMENT COMMENT '主键',
  `ename` varchar(255) DEFAULT NULL COMMENT '雇员名称',
  `salary` decimal(10,2) DEFAULT NULL COMMENT '薪水',
  `age` int(11) DEFAULT NULL COMMENT '年龄',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8

实体类

package pojo;

public class Employee {
	private int id;
	private String ename;//雇员名称
	private double salary;//薪水
	private int age;//年龄

	public String toString() {
		return "Employee [id=" + id + ", ename=" + ename + ", salary=" + salary + ", age=" + age + "]";
	}
	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	public String getEname() {
		return ename;
	}

	public void setEname(String ename) {
		this.ename = ename;
	}

	public double getSalary() {
		return salary;
	}

	public void setSalary(double salary) {
		this.salary = salary;
	}

	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}

}

数据库连接配置

# database connection parameters
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/ems?useUnicode=true&characterEncoding=utf-8
jdbc.username=root
jdbc.password=root
jdbc.initSize=1
jdbc.maxSize=3

数据库连接工具类

package util;

import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;

import org.apache.commons.dbcp.BasicDataSource;

public class DBUtil {
	private static BasicDataSource ds;
	static {
		//加载参数
		Properties p=new Properties();
		try {
			p.load(DBUtil.class.getClassLoader().getResourceAsStream("db.properties"));
			//获取数据库连接参数
			String driverClassName=p.getProperty("jdbc.driver");
			String url=p.getProperty("jdbc.url");
			String username=p.getProperty("jdbc.username");
			String password=p.getProperty("jdbc.password");
			String initialSize=p.getProperty("jdbc.initSize");
			String maxSize=p.getProperty("jdbc.maxSize");
			//创建连接池
			ds=new BasicDataSource();
			//设置连接池参数
			ds.setDriverClassName(driverClassName);
			ds.setUrl(url);
			ds.setUsername(username);
			ds.setPassword(password);
			ds.setInitialSize(Integer.parseInt(initialSize));
			ds.setMaxActive(Integer.parseInt(maxSize));
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	/*
	 * 由连接池创建的连接,其实现类由连接池提供.
	 */
	public static Connection getConnection() throws SQLException {
		return ds.getConnection();
	}
	/*
	 * 连接池提供的实现类,其close方法内部逻辑是,
	 * 将连接归还给连接池,即它会清空连接对象中的数据
	 * 并且将连接标记为空闲态
	 */
	public static void close(Connection con) {
		if(con!=null) {
			try {
				con.close();
			} catch (SQLException e) {
				e.printStackTrace();
				throw new RuntimeException("归还连接失败",e);
			}
		}
	}
}

数据库访问类

package dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import pojo.Employee;
import util.DBUtil;

public class EmployeeDAO {
	Connection con = null;
	/*
	 * 新增雇员
	 */
	public void save(Employee e){
		try {
			con = DBUtil.getConnection();
			String sql="insert into t_emp values(null,?,?,?)";
			PreparedStatement ps=con.prepareStatement(sql);
			ps.setString(1, e.getEname());
			ps.setDouble(2, e.getSalary());
			ps.setInt(3,e.getAge());
			ps.executeUpdate();
		} catch (SQLException e1) {
			//记日志（保留现场）
			e1.printStackTrace();
			/*
			 * 看异常能否恢复，如果不能够恢复
			 * (比如，数据库服务暂停等，一般我们称之为系统异常)，
			 * 要提示用户稍后重试。
			 * 如果能够恢复，则立即恢复
			 */
			throw new RuntimeException(e1);
		}finally {
			DBUtil.close(con);
		}
	}
	/*
	 *查询所有雇员信息
	 */
	public List<Employee>findAll(){
		List<Employee>list=new ArrayList<Employee>();
		try {
			con=DBUtil.getConnection();
			String sql="select * from t_emp";
			PreparedStatement ps=con.prepareStatement(sql);
			ResultSet rs=ps.executeQuery();
			while(rs.next()) {
				Employee e=new Employee();
				e.setId(rs.getInt("id"));
				e.setEname(rs.getString("ename"));
				e.setAge(rs.getInt("age"));
				e.setSalary(rs.getDouble("salary"));
				list.add(e);
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}finally {
			DBUtil.close(con);
		}
		return list;
	}
}

addEmp.html

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>添加员工</title>
</head>
<body style="font-size:30px;">
	<form action="addEmp" method="post">
		<fieldset>
			<legend>添加员工</legend>
			姓名：<input name="ename"><br>
			薪水：<input name="salary"><br>
			年龄：<input name="age"><br>
			<input type="submit" value="确定">
		</fieldset>
	</form>
</body>
</html>

新增servlet

package web;

import java.io.IOException;
import java.io.PrintWriter;

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 dao.EmployeeDAO;
import pojo.Employee;

@WebServlet("/addEmp")
public class AddEmpServlet extends HttpServlet {
	public void service(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		request.setCharacterEncoding("UTF-8");
		response.setCharacterEncoding("UTF-8");
		response.setContentType("text/html;charset=UTF-8");
		PrintWriter out=response.getWriter();
		EmployeeDAO dao = new EmployeeDAO();
		String ename=request.getParameter("ename");
		String salary=request.getParameter("salary");
		String age=request.getParameter("age");
		Employee emp=new Employee();
		emp.setEname(ename);
		emp.setSalary(Double.parseDouble(salary));
		emp.setAge(Integer.parseInt(age));
		try {
			dao.save(emp);
			out.println("<h1>添加成功！</h1>");
		} catch (Exception e) {
			e.printStackTrace();
			out.println("<h1>系统繁忙，请稍后重试！</h1>");
		}
		//容器会自动关闭out,这儿不调用out.close()也可以
		out.close();
	}
}

列表servlet

package web;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;

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 dao.EmployeeDAO;
import pojo.Employee;

@WebServlet("/listEmp")
public class ListEmpServlet extends HttpServlet {
	public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		request.setCharacterEncoding("UTF-8");
		response.setCharacterEncoding("UTF-8");
		response.setContentType("text/html;charset=UTF-8");
		PrintWriter out=response.getWriter();
		out.println("<table><tr><td>ID</td><td>ename</td><td>age</td><td>salary</td></tr>");
		EmployeeDAO dao=new EmployeeDAO();
		List<Employee>list=dao.findAll();
		for (Employee employee : list) {
			out.println("<tr><td>"+employee.getId()+"</td><td>"+employee.getEname()+"</td><td>"+employee.getAge()+"</td><td>"+employee.getSalary()+"</td></tr>");
		}
		out.println("</table>");
		out.close();
	}
}