1.Spring容器和SpringMVC容器的關係

Spring容器是一個父容器，SpringMVC容器是一個子容器，它繼承自Spring容器。因此，在SpringMVC容器中，可以訪問到Spring容器中定義的Bean，而在Spring容器中，無法訪問SpringMVC容器中定義的Bean。在Web開發中，Controller全部在SpringMVC中掃描，除了Controller之外的Bean，全部在Spring容器中掃描（Service、Dao），按這種方式掃描，掃描完完成後，Controller可以訪問到Service。

1. 為什麼不全部都在Spring中掃描   因為處理器對映器只會去SpringMVC中查詢到Controller，如果沒有，就找不到，不會去Spring中找，這就決定了，Controller必須在SpringMVC中掃描。
2. 為什麼不全部在SpringMVC中掃描   在SSM整合或者Spring+SpringMVC+JdbcTemplate中，可以全部在SpringMVC中掃描，但是，在SSH整合中，這種方式不允許。

最佳實踐：

1. Controller在SpringMVC中掃描，檢視解析器等在SpringMVC容器中配置
2. Spring中掃描Service、Dao已經其他元件，事務定義、資料來源定義都在Spring容器中配置

案例

匯入jar包

定義bean層

package com.sxt.bean;

public class User {
	private Integer id;
	
	private String username;
	
	private String password;

	public Integer getId() {
		return id;
	}

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

	public String getUsername() {
		return username;
	}

	public void setUsername(String username) {
		this.username = username;
	}

	public String getPassword() {
		return password;
	}

	public void setPassword(String password) {
		this.password = password;
	}

	@Override
	public String toString() {
		return "User [id=" + id + ", username=" + username + ", password=" + password + "]";
	}
	
}

 

定義dao層與實現類

package com.sxt.dao;

import java.util.List;

import com.sxt.bean.User;

public interface UserDao {
	public List<User> query();
}

package com.sxt.dao.impl;

import java.util.List;

import javax.annotation.Resource;

import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Repository;

import com.sxt.bean.User;
import com.sxt.dao.UserDao;
@Repository
public class UserDaoImpl implements UserDao{
	@Resource
	private JdbcTemplate template;
	@Override
	public List<User> query() {
		String Sql="select * from t_user";
				
		return template.query(Sql, new BeanPropertyRowMapper(User.class));
	}

}

 

定義Service和它的實現類

package com.sxt.service;

import java.util.List;

import com.sxt.bean.User;

public interface UserService {
	public List<User> query();
}

package com.sxt.service.impl;

import java.util.List;

import javax.annotation.Resource;

import org.springframework.stereotype.Service;

import com.sxt.bean.User;
import com.sxt.dao.UserDao;
import com.sxt.service.UserService;
@Service
public class UserServiceImpl implements UserService{
		@Resource
		private UserDao dao;
	@Override
	public List<User> query() {
		return dao.query();
	}

}

SpringMVC配置檔案

<!-- 開啟SpringMVC註解的方式 -->
	<mvc:annotation-driven >
	</mvc:annotation-driven>
		<!-- 開啟掃描 -->
	<context:component-scan base-package="com.sxt.controller" use-default-filters="false">
			<context:include-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
	</context:component-scan>

Spring的配置檔案

<context:component-scan base-package="com.sxt.dao.impl,com.sxt.service.impl" use-default-filters="true">
 			<context:exclude-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
 	</context:component-scan>
 	<bean class="org.springframework.jdbc.datasource.DriverManagerDataSource" id="dataSource">
 			<!-- 配置資料庫的相關資訊 -->
		<property name="driverClassName" value="com.mysql.jdbc.Driver" />
		<property name="url"
			value="jdbc:mysql://localhost:3306/pms?characterEncoding=utf-8" />
		<property name="username" value="root" />
		<property name="password" value="123456" />
 	</bean>
 	<bean class="org.springframework.jdbc.core.JdbcTemplate" id="template">
 		<property name="dataSource" ref="dataSource"></property>
 	</bean>

web.xml檔案中

分別載入spring和SpringMVC的配置

<?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" id="WebApp_ID" version="3.1">
  <display-name>SpringMVC-01-hello</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
  <context-param>
  		<param-name>contextConfigLocation</param-name>
  		<param-value>classpath:application.xml</param-value>
  </context-param>
  
	<listener>
		<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
	</listener>
 
	<servlet>
		<servlet-name>springmvc</servlet-name>
		<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
		<init-param>
			<param-name>contextConfigLocation</param-name>
			<param-value>classpath:Spring-MVC.xml</param-value>
		</init-param>
		<load-on-startup>1</load-on-startup>
	</servlet>
	<filter>
   <filter-name>encodingFilter</filter-name>
   <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
   <init-param>
       <param-name>encoding</param-name>
       <param-value>UTF-8</param-value>
   </init-param>
</filter>
<filter-mapping>
   <filter-name>encodingFilter</filter-name>
   <url-pattern>/*</url-pattern>
</filter-mapping>   
	<!-- Map all requests to the DispatcherServlet for handling -->
	<servlet-mapping>
		<servlet-name>springmvc</servlet-name>
		<url-pattern>/</url-pattern>
	</servlet-mapping>
	<servlet-mapping>
        <servlet-name>default</servlet-name>
        <url-pattern>*.jpg</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>default</servlet-name>
        <url-pattern>*.js</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>default</servlet-name>
        <url-pattern>*.css</url-pattern>
    </servlet-mapping>

</web-app>

自定義Controller

package com.sxt.controller;

import java.util.List;

import javax.annotation.Resource;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

import com.sxt.bean.User;
import com.sxt.service.UserService;

@Controller
public class UserController {
	@Resource
	private UserService userService;
	
	@RequestMapping("/query")
	public String query(Model m){
		 List<User> query = userService.query();
		 m.addAttribute("list",query);
		return "/user.jsp";
	}
}

在user頁面將資料提取出來

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!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>
  <c:forEach items="${list}" var="user">
  	${user.id }--${user.username }--${user.password }<br>
  </c:forEach>
</body>
</html>

效果測試

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