springmvc（5）：小结，通过map数据模型传递数据展示一个表

最新推荐文章于 2022-03-11 23:56:42 发布

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本文介绍了一个使用SpringMVC框架进行数据展示的例子，通过在控制器中获取静态数据并将其传递给视图，在list.jsp页面上展示这些数据。文章详细展示了代码实现过程，包括控制器、视图文件和数据实体类等。

今天实现了一个小例子，利用 springmvc 实现对数据的展示，没有使用数据库。后台的静态数据封装好了（getAll()方法，利用map.value()），利用SpringMVC_处理模型数据之Map，然后在显示文件 list.jsp 输出数据值（引入使用了JSTL标签<c ></c>）。

handlers：

package com.springmvc.crud.handlers;

import java.util.Map;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

import com.springmvc.crud.dao.EmployeeDao;

@Controller
public class EmployeeHandler {
	
	private EmployeeDao employeeDao ;
	
	@RequestMapping("/emps")
	public String list(Map<String,Object> map){
		System.out.println("111");
		map.put("employees", employeeDao.getAll());
		return"list";
	}
	
}

list.jsp：

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
   
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
<script type="text/javascript" src="scripts/jquery-1.9.1.min.js"></script>
<script type="text/javascript">
	$(function(){
		$(".delete").click(function(){
			var href = $(this).attr("href");
			$("form").attr("action", href).submit();			
			return false;
		});
	})
</script>
</head>
<body>
	//JSTL的标签
	<c:if test="${empty requestScope.employees }">
		通过使用标签库判断请求域的内容是否为null，检查得到没有任何员工信息..
	</c:if>
	<c:if test="${!empty requestScope.employees }">
		<table border="1" cellpadding="10" cellspacing="0">
			<tr>
				<th>ID</th>
				<th>LastName</th>
				<th>Email</th>
				<th>Gender</th>
				<th>Department</th>
				<th>Edit</th>
				<th>Delete</th>
			</tr>
			
			<c:forEach items="${requestScope.employees }" var="emp">
				<tr>
					<td>${emp.id }</td>
					<td>${emp.lastName }</td>
					<td>${emp.email }</td>
					<td>${emp.gender == 0 ? 'Female' : 'Male' }</td>
					<td>${emp.department.Department }</td>
					<td><a href="">Edit</a></td>
					<td><a href="">Delete</a></td>
				</tr>
			</c:forEach>
		</table>
	</c:if>
	<h1>hello</h1>
	employee_lists:" ${requestScope.employees}"
</body>
</html>

web.xml、dispacherservlet.cml 和数据实体类代码入下：

1.web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns="http://java.sun.com/xml/ns/javaee"
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
	id="WebApp_ID" version="2.5">

	<!-- 配置 DispatcherServlet -->
	<servlet>
		<servlet-name>dispatcherServlet</servlet-name>
		<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
		<init-param>
			<param-name>contextConfigLocation</param-name>
			<param-value>classpath:springmvc.xml</param-value>
		</init-param>	
		
		<load-on-startup>1</load-on-startup>
	</servlet>
	<servlet-mapping>
		<servlet-name>dispatcherServlet</servlet-name>
		<url-pattern>/</url-pattern>
	</servlet-mapping>
	
	<!-- 
	配置 org.springframework.web.filter.HiddenHttpMethodFilter: 可以把 POST 请求转为 DELETE 或 POST 请求 
	-->
	<filter>
		<filter-name>HiddenHttpMethodFilter</filter-name>
		<filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter-class>
	</filter>
	
	<filter-mapping>
		<filter-name>HiddenHttpMethodFilter</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>

</web-app>

2.springmvc.cml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:mvc="http://www.springframework.org/schema/mvc"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
		http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd">
	<!-- 配置自定扫描的包 -->
	<context:component-scan base-package="com.springmvc.crud"></context:component-scan>

	<!-- 配置视图解析器: 如何把 handler(xxx.java的method)方法 返回值return_value 解析为实际的物理视图 -->
	<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
		<property name="prefix" value="/WEB-INF/view/"></property>
		<property name="suffix" value=".jsp"></property>
	</bean>


</beans>

3.EmployeeDao.java

package com.springmvc.crud.dao;


import java.util.Collection;
import java.util.HashMap;
import java.util.Map;

import com.springmvc.crud.entities.Department;
import com.springmvc.crud.entities.Employee;


public class EmployeeDao {
	private static Map<Integer, Employee> employees = null;
	
	private DepartmentDao departmentDao;
	
	static{
		employees = new HashMap<Integer, Employee>();

		employees.put(1001, new Employee(1001, "E-AA", "aa@163.com", 1, new Department(101, "D-AA")));
		employees.put(1002, new Employee(1002, "E-BB", "bb@163.com", 1, new Department(102, "D-BB")));
		employees.put(1003, new Employee(1003, "E-CC", "cc@163.com", 0, new Department(103, "D-CC")));
		employees.put(1004, new Employee(1004, "E-DD", "dd@163.com", 0, new Department(104, "D-DD")));
		employees.put(1005, new Employee(1005, "E-EE", "ee@163.com", 1, new Department(105, "D-EE")));
	}
	
	private static Integer initId = 1006;
	
	public void save(Employee employee){
		if(employee.getId() == null){
			employee.setId(initId++);
		}
		
		employee.setDepartment(departmentDao.getDepartment(employee.getDepartment().getId()));
		employees.put(employee.getId(), employee);
	}
	
	public Collection<Employee> getAll(){
		return employees.values();
	}
	
	public Employee get(Integer id){
		return employees.get(id);
	}
	
	public void delete(Integer id){
		employees.remove(id);
	}
}

4.DepartmentDao.java

package com.springmvc.crud.dao;

import java.util.Collection;
import java.util.HashMap;
import java.util.Map;

import com.springmvc.crud.entities.Department;

public class DepartmentDao {

	private static Map<Integer, Department> departments = null;
	
	static{
		departments = new HashMap<Integer, Department>();
		
		departments.put(101, new Department(101, "D-AA"));
		departments.put(102, new Department(102, "D-BB"));
		departments.put(103, new Department(103, "D-CC"));
		departments.put(104, new Department(104, "D-DD"));
		departments.put(105, new Department(105, "D-EE"));
	}
	
	public Collection<Department> getDepartments(){
		return departments.values();
	}
	
	public Department getDepartment(Integer id){
		return departments.get(id);
	}
}

5.Employee.java

package com.springmvc.crud.entities;

import java.util.Date;

import org.springframework.format.annotation.DateTimeFormat;
import org.springframework.format.annotation.NumberFormat;

public class Employee {
	private Integer id;
	private String lastName;
	private String email;
	//1 male, 0 female
	private Integer gender;
	
	private Department department;

	public Integer getId() {
		return id;
	}

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

	public String getLastName() {
		return lastName;
	}

	public void setLastName(String lastName) {
		this.lastName = lastName;
	}

	public String getEmail() {
		return email;
	}

	public void setEmail(String email) {
		this.email = email;
	}

	public Integer getGender() {
		return gender;
	}

	public void setGender(Integer gender) {
		this.gender = gender;
	}

	public Department getDepartment() {
		return department;
	}

	public void setDepartment(Department department) {
		this.department = department;
	}
	
	
	public Employee(Integer id, String lastName, String email, Integer gender,
			Department department) {
		super();
		this.id = id;
		this.lastName = lastName;
		this.email = email;
		this.gender = gender;
		this.department = department;
	}

	@Override
	public String toString() {
		return "Employee [id=" + id + ", lastName=" + lastName + ", email=" + email + ", gender=" + gender
				+ ", department=" + department + "]";
	}

	public Employee() {
		// TODO Auto-generated constructor stub
	}
}

6.Department.java

package com.springmvc.crud.entities;

public class Department {
	private Integer id;
	private String Department;
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getDepartment() {
		return Department;
	}
	public void setDepartment(String department) {
		Department = department;
	}
	public Department(int id, String department) {
		super();
		this.id = id;
		Department = department;
	}
	public Department() {
		super();
		// TODO 自动生成的构造函数存根
	}
	@Override
	public String toString() {
		return "Department [id=" + id + ", Department=" + Department + "]";
	}
	
}