SpringMVC实现与CRUD整合
说明，该demo中使用List模拟了一套数据源，可以实现简单的crud操作，其中修改使用了SpringMVC的问号传参，删除操作使用了路径传参。
对比问号传参与路径传参：
问号传参，需要使用问号来拼接参数，在接受方，使用request.getParameter(“key”)来获取问号所传递过来的值，如果数据类型不为String，还需要手动转换。可以传递多个值，如果使用多个值，使用&来拼接，不会改变路径级别
路径传参，使用路径符号来传递参数，优点，可以不用做类型转换来直接获取其值。
路径传参也可以使用统配规则，如果同时统配和具体的url都满足，则以最具体的url来处理该请求。
Emp.java
package com.qfedu.bean;
public class Emp {
private int eid;
private String name;
private double salary;
public Emp() {
}
public Emp(int eid, String name, double salary) {
this.eid = eid;
this.name = name;
this.salary = salary;
}
@Override
public String toString() {
return "Emp{" +
"eid=" + eid +
", name='" + name + '\'' +
", salary=" + salary +
'}';
}
public int getEid() {
return eid;
}
public void setEid(int eid) {
this.eid = eid;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public double getSalary() {
return salary;
}
public void setSalary(double salary) {
this.salary = salary;
}
}
EmpController.java
RequestMapping
可以通过method来区分不同的请求方式
@RequestMapping(value = “/updateEmp”, method = RequestMethod.POST)代表处理post请求
@RequestMapping(value = “/updateEmp”, method = RequestMethod.GET)代表处理get请求
GETMapping，可以简化代码，专门用来处理get请求（4.3以后的Spring版本可用）
PostMapping，可以简化代码，专门用来处理post请求（4.3以后的Spring版本可用）
PathVariable路径传参的注解，可以实现路径传参。
package com.qfedu.controller;
import com.qfedu.bean.Emp;
import com.qfedu.service.IEmpService;
import com.qfedu.service.impl.EmpServiceImpl;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import java.util.List;
@Controller
@RequestMapping("/emp")
public class EmpController {
private IEmpService empService = new EmpServiceImpl();
/**
* 如果有了users请求，那么该方法会被调用，返回值为将来要渲染的页面
* @return
*/
@RequestMapping("/emps")
public String getUsersPage(Model model, HttpSession session){
List list = empService.getAllEmps();
model.addAttribute("list", list);
session.setAttribute("list", list);
return "emp.jsp";
}
@RequestMapping("/getEmpByEid")
public String getEmpByEid(HttpServletRequest request, Model model){
String seid = request.getParameter("eid");
int eid = seid == null ? -1 : Integer.parseInt(seid);
Emp emp = empService.getEmpByEid(eid);
model.addAttribute("emp", emp);
return "updateEmp.jsp";
}
//@RequestMapping(value = "/updateEmp", method = RequestMethod.POST)
@PostMapping("/updateEmp")
//public String updateEmp(HttpServletRequest request){
public String updateEmp(Emp e){
//System.out.println(request.getParameter("eid"));
System.out.println(e);
boolean flag = empService.updateEmp(e);
if(flag){
return "redirect:/emp/emps";
}
return "";
}
@GetMapping("/deleteByEid/{eid}")
public String deleteByEid(@PathVariable int eid){
//System.out.println(eid);
boolean flag = empService.deleteEmpByEid(eid);
if(flag){
return "redirect:/emp/emps";
}
return "";
}
}
IEmpService.java
package com.qfedu.service;
import com.qfedu.bean.Emp;
import java.util.List;
public interface IEmpService {
List getAllEmps();
Emp getEmpByEid(int eid);
boolean updateEmp(Emp emp);
boolean deleteEmpByEid(int eid);
}
EmpServiceImpl.java
package com.qfedu.service.impl;
import com.qfedu.bean.Emp;
import com.qfedu.dao.impl.EmpDaoImpl;
import com.qfedu.dao.IEmpDao;
import com.qfedu.service.IEmpService;
import java.util.List;
public class EmpServiceImpl implements IEmpService {
private IEmpDao empDao = new EmpDaoImpl();
@Override
public List getAllEmps() {
return empDao.getAllEmps();
}
@Override
public Emp getEmpByEid(int eid) {
return empDao.getEmpByEid(eid);
}
@Override
public boolean updateEmp(Emp emp) {
return empDao.updateEmp(emp);
}
@Override
public boolean deleteEmpByEid(int eid) {
return empDao.deleteEmpByEid(eid);
}
}
IEmpDao.java
package com.qfedu.dao;
import com.qfedu.bean.Emp;
import java.util.List;
public interface IEmpDao {
List getAllEmps();
Emp getEmpByEid(int eid);
boolean updateEmp(Emp emp);
boolean deleteEmpByEid(int eid);
}
EmpDaoImpl.java
package com.qfedu.dao.impl;
import com.qfedu.bean.Emp;
import com.qfedu.dao.IEmpDao;
import java.util.ArrayList;
import java.util.List;
public class EmpDaoImpl implements IEmpDao {
private static List emps = new ArrayList<>();
static {
for(int i = 0; i < 20; i++){
emps.add(new Emp(i + 1, "name " + i, 8000 + i * 100));
}
}
@Override
public List getAllEmps() {
return emps;
}
@Override
public Emp getEmpByEid(int eid) {
return emps.get(eid - 1);
}
@Override
public boolean updateEmp(Emp emp) {
try{
emps.set(emp.getEid() - 1, emp);
return true;
}catch (Exception e){
e.printStackTrace();
}
return false;
}
@Override
public boolean deleteEmpByEid(int eid) {
try{
emps.remove(eid -1 );
return true;
}catch (Exception e){
e.printStackTrace();
}
return false;
}
}
emp.jsp
<%--
Created by IntelliJ IDEA.
User: james
Date: 2020/3/3
Time: 4:04 PM
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
this is users page.
eid
name
salary
manage
${e.eid}
${e.name}
${e.salary}
update delete
updateEmp.jsp
<%--
Created by IntelliJ IDEA.
User: james
Date: 2020/3/3
Time: 4:39 PM
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
this is emp update page.
spring-mvc.xml
xmlns:mvc="http://www.springframework.org/schema/mvc"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">