SpringMVC学习笔记--中篇
SpringMVC学习笔记
文章目录
- SpringMVC学习笔记
-
- 1、跳转方式
-
- 1.1、ModelAndView
- 1.2、ServletAPI
- 1.3、SpringMVC
- 2、数据处理
-
- 2.1、映射类型
-
- 2.1.1、提交的域名和处理方法的参数名一致
- 2.1.2、提交的域名和处理方法的参数名不一致
- 2.1.3、提交的是一个对象
- 2.2、数据显示到前端
-
- 2.2.1、ModelAndView
- 2.2.2、ModelMap
- 2.2.3、Model
- 2.2.4、对比
- 2.3、乱码问题
- 3、整合SSM
-
- 3.1、数据库环境
- 3.2、基本环境搭建
- 3.3、建立基本结构和配置框架
- 3.4、Mybatis层编写
- 3.5、Spring层
- 3.6、SpringMVC层
1、跳转方式
重定向：当浏览器输入网址访问服务器时，服务器会返回另一个网址给浏览器，告诉浏览器，你用这个地址重新访问一下吧。典型的应用就是，网站迁移到新的服务器上了，但是老用户只知道旧的地址，这样就可以当用户访问旧地址时，通过重定向返回新的地址。
转发：当浏览器输入网址访问服务器时，服务器当前接口把请求转到另一个接口处理，这个过程都是服务器的行为，不会与浏览器有任何交互(即不会返回任何信息给浏览器)。
默认情况下使用的是转发，可以使用redirect：视图来进行重定向处理，视图解析器不会对重定向视图进行解析。重定向不可以访问WEB-INF目录下的资源。
1.1、ModelAndView
设置对象，根据view的名称。和视图解析器跳转到指定的页面。
页面：{视图解析器前缀}+viewName+{视图解析器后缀}
视图解析器：
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
<property name="prefix" value="/WEB-INF/pages/" />
<property name="suffix" value=".jsp" />
bean>
<bean name="/t1" class="com.yjr.controller.ControllerDemo"/>
对应的Controller类
//只要实现了Controller接口的类，说明这就是一个控制器了
public class ControllerDemo implements Controller {
@Override
public ModelAndView handleRequest(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws Exception {
ModelAndView modelAndView=new ModelAndView();
modelAndView.addObject("msg","test111");
modelAndView.setViewName("test");
return modelAndView;
}
}
1.2、ServletAPI
通过ServletAPI，不需要视图解析器。
- 通过HttpServletResponse进行输出
- 通过HttpServletResponse实现重定向
- 通过HttpServletResponse实现转发
@Controller
public class ResultGo {
@RequestMapping("/result/t1")
public void test1(HttpServletRequest req, HttpServletResponse rsp)
throws IOException {
rsp.getWriter().println("Hello,Spring BY servlet API");
}
@RequestMapping("/result/t2")
public void test2(HttpServletRequest req, HttpServletResponse rsp)
throws IOException {
rsp.sendRedirect("/index.jsp");
}
@RequestMapping("/result/t3")
public void test3(HttpServletRequest req, HttpServletResponse rsp)
throws Exception {
//转发
req.setAttribute("msg","/result/t3");
req.getRequestDispatcher("/WEB-INF/jsp/test.jsp").forward(req,rsp);
}
}
1.3、SpringMVC
通过SpringMVC来实现转发和重定向-无需视图解析器
测试前，需要将视图解析器注释。
public class ResultSpringMVC {
@RequestMapping("/rsm/t1")
public String test1() {
//转发--在没有配置视图解析器的时候，需要写全命名，路径
return "/WEB-INF/pages/index.jsp";
}
@RequestMapping("/rsm/t2")
public String test2() {
//转发二
return "forward:/index.jsp";
}
@RequestMapping("/rsm/t3")
public String test3() {
//重定向
return "redirect:/index.jsp";
}
通过SpringMVC来实现转发和重定向-有视图解析器
默认就是转发的方式。
重定向，不需要视图解析器，本质就是重新请求一个新的地方。（注意路径问题）
但也可以重定向另外一个请求。
@Controller
public class ResultSpringMVC2 {
@RequestMapping("/rsm2/t1")
public String test1(){
//转发:forward； 如果加了此关键字，视图解析器也不会对视图进行解析
return "forward:/WEB-INF/pages/test.jsp";
//return "forward:index";
}
@RequestMapping("/rsm2/hit")
public String doHit() {
//重定向
// return "redirect:/hit.jsp";
return "redirect:/WEB-INF/pages/test.jsp";
// redirect关键字加上后就不会对视图拼接处理了
}
@RequestMapping("/rsm2/t2")
public String test2() {
//重定向一个请求redirect:/rsm2/t1
//重定向--访问后地址栏变为http://localhost:8080/springmvc_04_controller_war_exploded/rsm2/t1
return "redirect:/rsm2/t1";
}
}
2、数据处理
2.1、映射类型
2.1.1、提交的域名和处理方法的参数名一致
提交数据：http://localhost:8080/user/getName?name=zs
处理方法：
@RequestMapping("/getName")
public String getName(String name, Model model){
//注意和@Param的区别
//当请求的参数名和实体类中的参数名不一致，使用@RequestParam注解解决映射问题
//http://localhost:8080/springmvc_04_controller_war_exploded/user/getName?username=zs
model.addAttribute("name",name);
System.out.println("name="+name);
return "user";
}
2.1.2、提交的域名和处理方法的参数名不一致
提交数据：http://localhost:8080/user/getName?username=zs
处理方法：使用@RequestParam()注解
@RequestMapping("/getName")
public String getName(@RequestParam("username") String name, Model model){
//注意和@Param的区别
//当请求的参数名和实体类中的参数名不一致，使用@RequestParam注解解决映射问题
//http://localhost:8080/user/getName?username=zs
model.addAttribute("name",name);
System.out.println("name="+name);
return "user";
}
2.1.3、提交的是一个对象
要提交的表单域和对象的属性名一致，蚕食使用对象即可
- 实体类
@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
private int id;
private String name;
private int age;
}
- 提交数据：http://localhost:8080/user/getUser?name=radan&id=1&age=15
- 处理方法：
//前端接受的是一个对象；id,name,age，如果使用对象，前端传递的参数名和对象名必须一致，否则就是null
@RequestMapping("/getUser")
public String getUser(User user,Model model)
{
System.out.println(user);
model.addAttribute("user",user);
return "test";
}
如果使用对象，前端传递的参数名和对象名必须一致，否则就是null
2.2、数据显示到前端
2.2.1、ModelAndView
public class ControllerTest1 implements Controller {
public ModelAndView handleRequest(HttpServletRequest httpServletRequest,
HttpServletResponse httpServletResponse) throws Exception {
//返回一个模型视图对象
ModelAndView mv = new ModelAndView();
mv.addObject("msg","ControllerTest1");
mv.setViewName("test");
return mv;
}
}
2.2.2、ModelMap
@RequestMapping("/hello")
public String hello(@RequestParam("username") String name, ModelMap model){
//封装要显示到视图中的数据
//相当于req.setAttribute("name",name);
model.addAttribute("name",name);
System.out.println(name);
return "hello";
}
2.2.3、Model
@RequestMapping("/ct2/hello")
public String hello(@RequestParam("username") String name, Model model){
//封装要显示到视图中的数据
//相当于req.setAttribute("name",name);
model.addAttribute("msg",name);
System.out.println(name);
return "test";
}
2.2.4、对比
- Model 只有寥寥几个方法只适合用于储存数据，简化了新手对于Model对象的操作和理解；
- ModelMap 继承了 LinkedMap ，除了实现了自身的一些方法，同样的继承 LinkedMap 的方法和特
性； - ModelAndView 可以在储存数据的同时，可以进行设置返回的逻辑视图，进行控制展示层的跳转。
2.3、乱码问题
SpringMVC给我们提供了一个过滤器 , 可以在web.xml中配置 .
修改了xml文件需要重启服务器！
<filter>
<filter-name>characterEncodingfilter-name>
<filter-class>org.springframework.web.filter.CharacterEncodingFilterfilter-class>
<init-param>
<param-name>encodingparam-name>
<param-value>utf-8param-value>
init-param>
filter>
<filter-mapping>
<filter-name>characterEncodingfilter-name>
<url-pattern>/*url-pattern>
filter-mapping>
有些极端情况下.这个过滤器对get的支持不好 .
处理方法：
- 修改tomcat配置文件：设置编码！
<Connector URIEncoding="utf-8" port="8080" protocol="HTTP/1.1"
connectionTimeout="20000"
redirectPort="8443" />
- 自定义过滤器
package com.yjr.filter;
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.Map;
/**
* 解决get和post请求 全部乱码的过滤器
*/
public class GenericEncodingFilter implements Filter {
public void destroy() {
}
public void doFilter(ServletRequest request, ServletResponse
response, FilterChain chain) throws IOException, ServletException {
//处理response的字符编码
HttpServletResponse myResponse=(HttpServletResponse) response;
myResponse.setContentType("text/html;charset=UTF-8");
// 转型为与协议相关对象
HttpServletRequest httpServletRequest = (HttpServletRequest)
request;
// 对request包装增强
HttpServletRequest myrequest = new
MyRequest(httpServletRequest);
chain.doFilter(myrequest, response);
}
public void init(FilterConfig filterConfig) throws
ServletException {
}
}
//自定义request对象，HttpServletRequest的包装类
class MyRequest extends HttpServletRequestWrapper {
private HttpServletRequest request;
//是否编码的标记
private boolean hasEncode;
//定义一个可以传入HttpServletRequest对象的构造函数，以便对其进行装饰
public MyRequest(HttpServletRequest request) {
super(request);// super必须写
this.request = request;
}
public Map getParameterMap() {
// 先获得请求方式
String method = request.getMethod();
if (method.equalsIgnoreCase("post")) {
// post请求
try {
// 处理post乱码
request.setCharacterEncoding("utf-8");
return request.getParameterMap();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
} else if (method.equalsIgnoreCase("get")) {
// get请求
Map<String, String[]> parameterMap =
request.getParameterMap();
if (!hasEncode) { // 确保get手动编码逻辑只运行一次
for (String parameterName : parameterMap.keySet()) {
String[] values = parameterMap.get(parameterName);
if (values != null) {
for (int i = 0; i < values.length; i++) {
try {
// 处理get乱码
values[i] = new String(values[i]
.getBytes("ISO-8859-1"), "utf-8");
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
}
}
}
hasEncode = true;
}
return parameterMap;
}
return super.getParameterMap();
}
//取一个值
@Override
public String getParameter(String name) {
Map<String, String[]> parameterMap = getParameterMap();
String[] values = parameterMap.get(name);
if (values == null) {
return null;
}
return values[0]; // 取回参数的第一个值
}
//取所有值
@Override
public String[] getParameterValues(String name) {
Map<String, String[]> parameterMap = getParameterMap();
String[] values = parameterMap.get(name);
return values;
}
}
然后在web.xml中配置这个过滤器即可！
3、整合SSM
3.1、数据库环境
CREATE DATABASE `ssmbuild`;
USE `ssmbuild`;
DROP TABLE IF EXISTS `books`;
CREATE TABLE `books` (
`bookID` INT(10) NOT NULL AUTO_INCREMENT COMMENT '书id',
`bookName` VARCHAR(100) NOT NULL COMMENT '书名',
`bookCounts` INT(11) NOT NULL COMMENT '数量',
`detail` VARCHAR(200) NOT NULL COMMENT '描述',
KEY `bookID` (`bookID`)
) ENGINE=INNODB DEFAULT CHARSET=utf8
INSERT INTO `books`(`bookID`,`bookName`,`bookCounts`,`detail`)VALUES
(1,'Java',1,'从入门到放弃'),
(2,'MySQL',10,'从删库到跑路'),
(3,'Linux',5,'从进门到进牢');
3.2、基本环境搭建
导入相关依赖
<dependencies>
<dependency>
<groupId>junitgroupId>
<artifactId>junitartifactId>
<version>4.12version>
dependency>
<dependency>
<groupId>mysqlgroupId>
<artifactId>mysql-connector-javaartifactId>
<version>8.0.31version>
dependency>
<dependency>
<groupId>com.mchangegroupId>
<artifactId>c3p0artifactId>
<version>0.9.5.2version>
dependency>
<dependency>
<groupId>javax.servletgroupId>
<artifactId>servlet-apiartifactId>
<version>2.5version>
dependency>
<dependency>
<groupId>javax.servlet.jspgroupId>
<artifactId>jsp-apiartifactId>
<version>2.2version>
dependency>
<dependency>
<groupId>javax.servletgroupId>
<artifactId>jstlartifactId>
<version>1.2version>
dependency>
<dependency>
<groupId>org.mybatisgroupId>
<artifactId>mybatisartifactId>
<version>3.5.2version>
dependency>
<dependency>
<groupId>org.mybatisgroupId>
<artifactId>mybatis-springartifactId>
<version>2.0.2version>
dependency>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-webmvcartifactId>
<version>5.1.9.RELEASEversion>
dependency>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-jdbcartifactId>
<version>5.1.9.RELEASEversion>
dependency>
<dependency>
<groupId>org.projectlombokgroupId>
<artifactId>lombokartifactId>
<version>1.18.24version>
dependency>
<dependency>
<groupId>log4jgroupId>
<artifactId>log4jartifactId>
<version>1.2.17version>
dependency>
<dependency>
<groupId>org.slf4jgroupId>
<artifactId>slf4j-apiartifactId>
<version>1.7.25version>
dependency>
<dependency>
<groupId>org.slf4jgroupId>
<artifactId>slf4j-simpleartifactId>
<version>1.7.25version>
<scope>testscope>
dependency>
dependencies>
Maven资源过滤设置
<build>
<resources>
<resource>
<directory>src/main/javadirectory>
<includes>
<include>**/*.propertiesinclude>
<include>**/*.xmlinclude>
includes>
<filtering>falsefiltering>
resource>
<resource>
<directory>src/main/resourcesdirectory>
<includes>
<include>**/*.propertiesinclude>
<include>**/*.xmlinclude>
includes>
<filtering>falsefiltering>
resource>
resources>
build>
** 建立基本结构和配置框架！**
3.3、建立基本结构和配置框架
- 建立pojo，controller，mapper，service层
- 编写mybatis-config.xml配置文件
DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
configuration>
- 编写applicationContext.xm配置文件
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-
beans.xsd">
beans>
3.4、Mybatis层编写
- 数据库配置文件db.properties
jdbc.driver=com.mysql.cj.jdbc.Driver
jdbc.jdbcUrl=jdbc:mysql://localhost:3306/ssmbuild?useSSl=true;useUnicode=true;characterEncoding=utf8;serverTimezone=UTC
jdbc.username=root
jdbc.password=123456
- 编写mybatis的核心配置文件
DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<settings>
<setting name="logImpl" value="LOG4J"/>
settings>
<typeAliases >
<package name="com.yjr.pojo"/>
typeAliases>
<mappers>
<mapper class="com.yjr.mapper.BookMapper"/>
mappers>
configuration>
- 编写实体类并使用lombok插件
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Books {
private int bookID;
private String bookName;
private int bookCounts;
private String detail;
}
- 编写mapper层的mapper接口
public interface BookMapper {
int addBook(Books book);
List<Books> allBook();
//根据id删除一个Book
int deleteBookById(int bookID);
//根据id查询,返回一个Book
Books queryBookByName(String bookName);
}
- 编写接口对应的Mapper.xml文件。需要导入Myabtis的包
DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"https://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.yjr.mapper.BookMapper">
<insert id="addBook" parameterType="books">
insert into books(bookID,bookName,bookCounts,detail) values(#{bookID},#{bookName},#{bookCounts},#{detail})
insert>
<delete id="deleteBookById">
delete from books where bookID=#{bookID}
delete>
<select id="allBook" resultType="books">
select * from books
select>
<select id="queryBookByName" resultType="books">
select * from books where bookName = #{bookName}
select>
mapper>`
- 编写service层的接口和实现类
接口
public interface BookService {
int addBook(Books book);
List<Books> allBook();
int deleteBookById(int bookID);
Books queryBookByName(String bookName);
}
实现类
//@Service.---这个也可在xml中配置，这里暂时使用的是配置版
public class BookServiceImpl implements BookService {
@Autowired
private BookMapper bookMapper;
public void setBookMapper(BookMapper bookMapper) {
this.bookMapper = bookMapper;
}
public int addBook(Books book) {
return bookMapper.addBook(book);
}
public List<Books> allBook() {
return bookMapper.allBook();
}
public int deleteBookById(int bookID) {
return bookMapper.deleteBookById(bookID);
}
public Books queryBookByName(String bookName) {
return bookMapper.queryBookByName(bookName);
}
}
Mybatis层暂时需要配置这些
3.5、Spring层
- 配置Spring整合MyBatis，我们这里数据源使用c3p0连接池
- 编写Spring整合Mybatis的相关的配置文件； spring-dao.xml
<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"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
https://www.springframework.org/schema/context/spring-context.xsd">
<context:property-placeholder location="classpath:db.properties"/>
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="driverClass" value="${jdbc.driver}"/>
<property name="jdbcUrl" value="${jdbc.jdbcUrl}"/>
<property name="user" value="${jdbc.username}"/>
<property name="password" value="${jdbc.password}"/>
<property name="maxPoolSize" value="30"/>
<property name="minPoolSize" value="10"/>
<property name="autoCommitOnClose" value="false"/>
<property name="checkoutTimeout" value="10000"/>
<property name="acquireRetryAttempts" value="2"/>
bean>
<bean name="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="dataSource"/>
<property name="configLocation" value="classpath:mybatis-config.xml"/>
bean>
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
<property name="basePackage" value="com.yjr.mapper"/>
bean>
beans>
- Spring整合service层
<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"
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.xsd">
<context:component-scan base-package="com.yjr.service" />
<bean id="BookServiceImpl" class="com.yjr.service.impl.BookServiceImpl">
<property name="bookMapper" ref="bookMapper"/>
bean>
<bean id="transactionManager"
class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dataSource" />
bean>
beans>
Spring层搞定!
3.6、SpringMVC层
- web.xml
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
<servlet>
<servlet-name>DispatcherServletservlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServletservlet-class>
<init-param>
<param-name>contextConfigLocationparam-name>
<param-value>classpath:applicationContext.xmlparam-value>
init-param>
<load-on-startup>1load-on-startup>
servlet>
<servlet-mapping>
<servlet-name>DispatcherServletservlet-name>
<url-pattern>/url-pattern>
servlet-mapping>
<filter>
<filter-name>encodingFilterfilter-name>
<filter-class>
org.springframework.web.filter.CharacterEncodingFilter
filter-class>
<init-param>
<param-name>encodingparam-name>
<param-value>utf-8param-value>
init-param>
filter>
<filter-mapping>
<filter-name>encodingFilterfilter-name>
<url-pattern>/*url-pattern>
filter-mapping>
<session-config>
<session-timeout>15session-timeout>
session-config>
web-app>
- spring-mvc.xml
<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.xsd
http://www.springframework.org/schema/mvc
https://www.springframework.org/schema/mvc/spring-mvc.xsd">
<mvc:annotation-driven />
<mvc:default-servlet-handler/>
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="viewClass" value="org.springframework.web.servlet.view.JstlView" />
<property name="prefix" value="/WEB-INF/jsp/" />
<property name="suffix" value=".jsp" />
bean>
<context:component-scan base-package="com.yjr.controller" />
beans>
- Spring配置整合文件，applicationContext.xml
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd">
<import resource="spring-dao.xml"/>
<import resource="spring-service.xml"/>
<import resource="spring-mvc.xml"/>
beans>
配置文件，暂时结束!