SSM笔记-SpringMVC的CRUD和静态资源

其他 2018-08-13 18:28:30 阅读次数: 0

1、处理静态资源
①通过DispatcherServlet配置请求映射后,获取静态资源的请求(通过url获取静态资源时),也会被当成普通请求处理，如果想配置请求映射后还能通过url的形式获取静态资源的话,则需要到springmvc配置文件中配置
②解决方法：在springmvc配置文件中配置mvc:default-servlet-handler标签

2、CRUD
步骤：
①创建Bean(数据模型+getset方法)
②创建对应的Dao(根据数据模型写对应的增删查改方法,如果对应的Bean中还有其他Bean的类对象,则需要使用@Autowired修饰这个类对象)
③创建Handler类,编写一些调用增删查改的action逻辑
④编写调用action的页面和显示结果的页面

注意：
①Dao中, 如果对应的Bean中还有其他Bean的类对象,则需要使用@Autowired修饰这个类对象
②如果要处理静态资源, 则需要到springmvc配置文件中配置mvc:default-servlet-handler标签
③提供修改功能的页面里面的form标签的action需要设为绝对路径,因为进入该页面的时候,路径会变成指向这个页面的对应action的路径,如果不设置绝对路径,路径就会变成action路径之下的子路径,这样就会无法重定向回显示页面,要这样写才行:
action="${pageContext.request.contextPath}/actionName
④Handler类中, 修改操作时,不显示及不提交某一个指定参数,所以正常情况下,该参数的值为空,为了让这个不允许修改或不出现在页面的参数不被设为空,这里需要通过@ModelAttribute,每次执行操作前都通过dao获取一次指定id的所有参数值
⑤上一点中被@ModelAttribute修饰的方法中需要使用Map来把查询到的数据存起来, 这个时候Map的key需要是被查询的Bean的首字母小写的类名,不然会无效,不允许修改或不出现到页面的参数,在更新后会被改为空

3、web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" version="3.1">
  <display-name>SpringMVC_7_CRUD</display-name>
  <servlet>
    <servlet-name>springDispatcherServlet</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>springDispatcherServlet</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>
  <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>

4、springmvc.xml

<?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.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.3.xsd">

    <!-- 配置自动扫描包 -->
    <context:component-scan base-package="com.test.springmvc"></context:component-scan>

    <!-- 配置视图解析器,把handler返回值解析为实际视图 -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/views/"></property>
        <property name="suffix" value=".jsp"></property>
    </bean>

    <!-- 处理静态资源 -->
    <!-- 通过DispatcherServlet配置请求映射后,获取静态资源的请求(通过url获取静态资源时),也会被当成普通请求处理 -->
    <!-- 解决方法：配置mvc:default-servlet-handler标签 -->
    <mvc:default-servlet-handler/>
    <mvc:annotation-driven></mvc:annotation-driven>

</beans>

5、Info.java

package com.test.springmvc.bean;

import org.springframework.stereotype.Repository;

@Repository
public class Info {

    Integer infoId;
    String infoName;
    String infoDesc;
    Detail detail;

    public Info() {}

    public Info(Integer infoId, String infoName, String infoDesc, Detail detail) {
        super();
        this.infoId = infoId;
        this.infoName = infoName;
        this.infoDesc = infoDesc;
        this.detail = detail;
    }
    public Integer getInfoId() {
        return infoId;
    }
    public void setInfoId(Integer infoId) {
        this.infoId = infoId;
    }
    public String getInfoName() {
        return infoName;
    }
    public void setInfoName(String infoName) {
        this.infoName = infoName;
    }
    public String getInfoDesc() {
        return infoDesc;
    }
    public void setInfoDesc(String infoDesc) {
        this.infoDesc = infoDesc;
    }
    public Detail getDetail() {
        return detail;
    }
    public void setDetail(Detail detail) {
        this.detail = detail;
    }
}

6、Detail.java

package com.test.springmvc.bean;

public class Detail {

    Integer detailId;
    String detailName;

    public Detail() {}

    public Detail(Integer detailId, String detailName) {
        super();
        this.detailId = detailId;
        this.detailName = detailName;
    }

    public Integer getDetailId() {
        return detailId;
    }

    public void setDetailId(Integer detailId) {
        this.detailId = detailId;
    }

    public String getDetailName() {
        return detailName;
    }

    public void setDetailName(String detailName) {
        this.detailName = detailName;
    }

}

7、InfoDao.java

package com.test.springmvc.dao;

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

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;

import com.test.springmvc.bean.Detail;
import com.test.springmvc.bean.Info;

@Repository
public class InfoDao {

    private static Map<Integer, Info>map = null;

    @Autowired
    private DetailDao detailDao;

    static{
        map=new HashMap<Integer,Info>();
        map.put(1, new Info(1, "infoA", "DescA", new Detail(1, "detailA")));
        map.put(2, new Info(2, "infoB", "DescB", new Detail(2, "detailB")));
        map.put(3, new Info(3, "infoC", "DescC", new Detail(3, "detailC")));
        map.put(4, new Info(4, "infoD", "DescD", new Detail(3, "detailD")));
    }

    public Collection<Info> getAll(){
        return map.values();
    }
    public Info getById(Integer id){
        return map.get(id);
    }
    public boolean add(Info info){
        map.put(map.size()+1, info);
        return true;
    }
    public boolean delete(Integer id){
        map.remove(id);
        return true;
    }
    public boolean update(Info info){
        if(info.getInfoId()!=null){
            info.setDetail(detailDao.getById(info.getDetail().getDetailId()));
            map.put(info.getInfoId(), info);
            return true;
        }else{
            return false;
        }
    }
}

8、DetailDao.java

package com.test.springmvc.dao;

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

import org.springframework.stereotype.Repository;

import com.test.springmvc.bean.Detail;

@Repository
public class DetailDao {

    private static Map<Integer, Detail>map = null;

    static{
        map=new HashMap<Integer,Detail>();
        map.put(1, new Detail(1, "detailA"));
        map.put(2, new Detail(2, "detailB"));
        map.put(3, new Detail(3, "detailC"));
        map.put(4, new Detail(3, "detailD"));
    }

    public Collection<Detail>getAll(){
        return map.values();
    }
    public Detail getById(Integer id){
        return map.get(id);
    }
    public boolean add(Detail detail){
        map.put(map.size()+1, detail);
        return true;
    }
    public boolean delete(Integer id){
        map.remove(id);
        return true;
    }
    public boolean update(Integer id,Detail detail){
        if(map.get(id)!=null){
            map.put(id, detail);
            return true;
        }else{
            return false;
        }
    }
}

9、Handler.java

package com.test.springmvc.handlers;

import java.util.Map;

import org.jcp.xml.dsig.internal.MacOutputStream;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;

import com.test.springmvc.bean.Detail;
import com.test.springmvc.bean.Info;
import com.test.springmvc.dao.DetailDao;
import com.test.springmvc.dao.InfoDao;

@Controller
public class Handler {

    @Autowired
    public InfoDao infoDao;

    @Autowired
    public DetailDao detailDao;

    //修改操作时,不显示及不提交某一个指定参数,所以正常情况下,该参数的值为空,为了让这个不允许修改或不出现在页面的参数不被设为空,这里需要通过@ModelAttribute,每次执行操作前都通过dao获取一次指定id的所有参数值
    //注意：这里map的key为修改操作方法中参数Info类的首字母小写,不然会无效,不允许修改或不出现到页面的参数,在更新后会被改为空
    @ModelAttribute
    public void getInfo(@RequestParam(value="infoId",required=false)Integer infoId,Map<String, Object>map ){
        if(infoId!=null){
            map.put("info", infoDao.getById(infoId));
        }
    }

    @RequestMapping("/list")
    public String show(Map<String, Object>map){
        System.out.println("list");
        map.put("infos", infoDao.getAll());
        System.out.println(map);
        return "list";
    }

    @RequestMapping(value="/emp",method=RequestMethod.GET)
    public String addPage(Map<String,Object>map){
        map.put("details", detailDao.getAll());
        map.put("infos", new Info());
        return "edit";
    }

    @RequestMapping(value="/emp",method=RequestMethod.POST)
    public String save(Info info){
        info.getDetail().setDetailName(detailDao.getById(info.getDetail().getDetailId()).getDetailName());
        info.setDetail(info.getDetail());
        infoDao.add(info);
        return "redirect:/list";
    }

    @RequestMapping(value="/emp/{id}",method=RequestMethod.DELETE)
    public String delete(@PathVariable Integer id){
        System.out.println("delete id:"+id);
        infoDao.delete(id);
        return "redirect:/list";
    }

    @RequestMapping(value="/emp/{id}",method=RequestMethod.GET)
    public String updatePage(@PathVariable Integer id,Map<String,Object>map){
        map.put("details", detailDao.getAll());
        map.put("infos", infoDao.getById(id));
        return "edit";
    }

    @RequestMapping(value="/emp",method=RequestMethod.PUT)
    public String update(Info info){
        System.out.println("update getInfoName:"+info.getInfoName());
        infoDao.update(info);
        return "redirect:/list";
    }
}

10、index.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!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>
</head>
<body>
    <a href="list">list data</a>
    <br><br>
</body>
</html>

11、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>Info list</title>
</head>
<body>
    <a href="emp">Add info</a>
    <br><br>
    <a href="/SpringMVC_7_CRUD/statsFile/jstl.jar">静态资源</a>
    <br><br>

    <c:if test="${empty requestScope.infos}">
        no data
    </c:if>
    <c:if test="${!empty requestScope.infos}">
        <table border="1" cellpadding="10" cellspacing="0">
            <tr>
                <td>infoId</td>
                <td>infoName</td>
                <td>infoDesc</td>
                <td>detailId</td>
                <td>detailName</td>
                <td>Update</td>
                <td>Delete</td>
            </tr>
            <c:forEach items="${requestScope.infos}" var="infoData">
                <tr>
                <td>${infoData.infoId}</td>
                <td>${infoData.infoName}</td>
                <td>${infoData.infoDesc}</td>
                <td>${infoData.detail.detailId}</td>
                <td>${infoData.detail.detailName}</td>
                <td><a href="emp/${infoData.infoId}">Update</a></td>
                <td>
                    <form method="post" action="emp/${infoData.infoId}">
                        <input type="hidden" name="_method" value="DELETE">
                        <input type="submit" name="submit" value="Delete">
                    </form>
                </td>
            </tr>
            </c:forEach>
        </table>
    </c:if>
</body>
</html>

12、edit.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>
<%@ 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>Add Info</title>
</head>
<body>

    <!-- 这里action需要设为绝对路径,因为进入edit的时候,路径会变成/emp,如果不设置绝对路径,路径就会变成/emp之下的子路径,这样就会无法重定向回显示页面 -->
    <form:form method="POST" action="${pageContext.request.contextPath}/emp" modelAttribute="infos">
        <c:if test="${infos.infoId!=null}">
            <!-- _method不能用form:hidden标签,因为modelAttribut对应的bean没有_method属性 -->
            <input type="hidden" name="_method" value="PUT">
        </c:if>
        infoId:<form:input path="infoId"/>
        <br>
        <c:if test="${infos.infoId==null}">
        infoName:<form:input path="infoName"/>
        <br>
        </c:if>
        infoDesc:<form:input path="infoDesc"/>
        <br>
        detail:<form:select path="detail.detailId" items="${details}" itemLabel="detailName" itemValue="detailId"></form:select>
        <br>
        <input type="submit" value="submit">
    </form:form>

</body>
</html>

13、项目目录
项目目录

14、demo
https://download.csdn.net/download/qq_22778717/10601060

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