SpringMVC学习(二)--实现简单用户登录

1.搭建框架

　　创建Maven项目并配置pom.xml:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion>
<groupId>com.lq</groupId>
<artifactId>Springmvc01</artifactId>
<packaging>war</packaging>
<version>0.0.1-SNAPSHOT</version>

<!-- 设置UTF-8编码格式 -->
<properties>
<!-- 文件拷贝时的编码 -->
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<!-- 编译时的编码 -->
<maven.compiler.encoding>UTF-8</maven.compiler.encoding>
<!-- 自定义常量，在依赖中可以通过${名字}的方式进行引用 -->
<spring.version>4.3.14.RELEASE</spring.version>
</properties>
<dependencies>
<!-- springmvc配置 -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>${spring.version}</version>
</dependency>
<!-- servlet配置 -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
<scope>provided</scope>
</dependency>
<!-- 流程处理标签配置 -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<!-- spring相关配置 -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context-support</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-orm</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>${spring.version}</version>
</dependency>
<!-- hibernate配置 -->
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>5.1.12.Final</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-validator</artifactId>
<version>6.0.2.Final</version>
</dependency>
<!-- 连接池配置 -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.1.6</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.41</version>
</dependency>
<!-- 单元测试配置 -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
</dependencies>
<!-- jdk版本配置 -->
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
</plugins>
</build>
</project>

2.配置web.xml前端控制器[有两种常见配置，*.do或者/　　

<?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>Springmvc01</display-name>
<context-param>
<param-name>appName</param-name>
<param-value>Springmvc01-Hibernate-用户登录</param-value>
</context-param>
<!-- 整合Spring和 web应用,这里负责加载父容器,父容器对应的配置文件是classpath:applicationContext.xml -->
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:app*.xml</param-value>
</context-param>

<!-- 过滤器处理中文乱码 -->
<!--提交数据时如果需要传送中文，请使用post提交-->
<filter>
<filter-name>encoder</filter-name>
<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>UTF-8</param-value><!-- 这里和页面的编码字符集一致 -->
</init-param>
</filter>
<filter-mapping>
<filter-name>encoder</filter-name>
<servlet-name>lq</servlet-name>
</filter-mapping>

<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<!-- 配置前端控制器，它负责加载子容器，子容器配置文件是/WEB-INF/lq-servlet.xml -->
<servlet>
<servlet-name>lq</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<!-- 随系统启动 -->
<load-on-startup>2</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>lq</servlet-name>
<url-pattern&g
11469
t;*.do</url-pattern>
</servlet-mapping>

<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>

3.SpringMVC应用中的父子容器的概念

　　在Spring整体框架的核心概念中，容器是核心思想，就是用来管理Bean的整个生命周期的，而在一个项目中，容器不一定只有一个，Spring中可以包括多个容器，而且容器有上下层关系，目前最常见的一种场景就是在一个项目中引入Spring和SpringMVC这两个框架，那么它其实就是两个容器，Spring是父容器，SpringMVC是其子容器，并且在Spring父容器中注册的Bean对于SpringMVC容器中是可见的，而在SpringMVC容器中注册的Bean对于Spring父容器中是不可见的，也就是子容器可以看见父容器中的注册的Bean，反之就不行。

　　子容器中一般配置和web应用相关的组件，例如ViewResolver视图解析器、控制器等。父容器中配置和web应用不直接相关的组件，例如连接池、SessionFactory、业务Bean等.

　　

４．添加Servlet相关的核心配置

惯例：位于WEB-INF目录下，名称为<servlet的名称>-servlet.xml
例如/WEB-INF/lq-servlet.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:mvc="http://www.springframework.org/schema/mvc"
xmlns:p="http://www.springframework.org/schema/p"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.3.xsd 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/tx http://www.springframework.org/schema/tx/spring-tx-4.3.xsd"> 
<!-- 打开mvc应用中的注解支持 -->
<mvc:annotation-driven validator="valid1"/>

<!-- 配置视图解析器，将逻辑地址名转换为物理地址，其中prefix用于设置前缀，suffix用于设置后缀，viewClass用于设置视图类型。例如
返回视图名称为abc，则对应的物理地址为“前缀”+逻辑地址名+"后缀"构成.ViewClass允许用户定义各种视图类型，例如返回pdf、Excel等 -->
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"
p:prefix="/WEB-INF/content/" p:suffix=".jsp"
p:viewClass="org.springframework.web.servlet.view.JstlView"/>

<!-- 启用Hinbernate提供的校验器 -->
<bean id="valid1"
class="org.springframework.validation.beanvalidation.LocalValidatorFactoryBean">
<property name="providerClass" value="org.hibernate.validator.HibernateValidator"></property>
</bean>

<!-- 定义控制器 -->
<context:component-scan base-package="com.lq.action">
<context:include-filter type="annotation"
expression="org.springframework.stereotype.Controller"/>
</context:component-scan>
</beans>

5.定义控制器

package com.lq.action;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.validation.Errors;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import com.lq.action.group.UserGroup;
import com.lq.entity.UserBean;

@Controller//用于标识是处理器类
@RequestMapping("/")// 定义在类上则类似于Struts2中的名空间,给类中的所有方法添加了一个名空间
public class UserController {
/*
@RequestMapping(value = "login", method = RequestMethod.GET)
public ModelAndView login()throws Exception{
ModelAndView mv = new ModelAndView();
UserBean user = new UserBean();
mv.addObject("user", user);
mv.setViewName("user/login");
return mv;

ModelAndView:
简单理解它是将后台返回的数据传递给View层,同时包含一个要访问的View层的URL地址,当控制器处理完请求后，通常控制器会将包含视图名称以及一些模型属性的ModelAndView对象返回给DispatcherServlet。因此，在控制器中会构造一个ModelAndView对象
ModelAndView作用
1)设置转向地址
2)将底层获取的数据进行存储（或者封装）
3)最后将数据传递给View
ModelAndView的用法：
先创建ModelAndView对象，再通过它的方法去设置数据与转发的视图名
ModelAndView modelAndView = new ModelAndView();构建对象
modelAndView.setViewName("m06");  设置逻辑视图名
modelAndView.addObject("message", "Hello World, Hello Kitty");添加需要显示的数据
*/

//映射login()方法到get请求的login.do上
@RequestMapping(value = "login", method = RequestMethod.GET)
public String login(Model model) throws Exception {
UserBean user = new UserBean();
model.addAttribute("user", user);
return "user/login";
}

/*
* 在Controller方法上添加注解@Validated，启动服务器端数据校验
* 通过分组区分不同方法的数据校验和定义校验执行顺序（前面的校验没有通过则后续校验不执行）
* 实现方法：采用旗标接口实现,定义如下接口和类
@GroupSequence({UserFirstGroup.class,UserSecondGroup.class})设置顺序
public interface UserGroup  {       }
public Class UserFirstGroup {       }
public Class UserSecondGroup{       }
@NotEmpty(message="用户名称不能为空!",groups=UserFirstGroup.class)
@Length(min=6,max=20,message="用户名称只能在6到20个字符之间!",groups=UserSecondGroup.class)
private String username;
*/
@RequestMapping(value="login" ,method=RequestMethod.POST)
public String login(@Validated(UserGroup.class)@ModelAttribute("user") UserBean user, Errors errors) {
System.out.println(user);
if (errors.hasErrors())
return "user/login";
return "show";
}
}

旗标接口实现类和接口:

package com.lq.action.group;
import javax.validation.GroupSequence;
@GroupSequence({UserFirstGroup.class,UserSecondGroup.class})//设置顺序
public interface UserGroup {}

package com.lq.action.group;
public class UserFirstGroup {}

package com.lq.action.group;
public class UserSecondGroup {}

实体类:

package com.lq.entity;

import java.util.Date;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import static javax.persistence.GenerationType.IDENTITY;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Transient;
import javax.validation.constraints.NotEmpty;

import org.hibernate.validator.constraints.Length;

import com.lq.action.group.UserFirstGroup;
import com.lq.action.group.UserSecondGroup;

@Entity(name = "t_users")
public class UserBean implements java.io.Serializable {

private static final long serialVersionUID = 5385542861402736914L;

@Id
@GeneratedValue(strategy = IDENTITY)
@Column(name = "id", unique = true, nullable = false)
private Long id;

@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "role_id", nullable = false)
private RoleBean role=new RoleBean();

@NotEmpty(message="用户名称不能为空!",groups=UserFirstGroup.class)
@Length(min=6,max=10,message="用户名称只能在6到10个字符之间",groups=UserSecondGroup.class)
@Column(name = "username", unique = true, nullable = false)
private String username;

@NotEmpty(message="用户口令不能为空!",groups=UserFirstGroup.class)
@Column(name = "password", nullable = false, length = 20)
private String password;

@Transient
private String repassword;

@Column(columnDefinition="timestamp default current_timestamp")
private Date birth;

@Column(columnDefinition="boolean default 1")
private Boolean sex;

public UserBean() {
}

public Long getId() {
return this.id;
}

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

public RoleBean getRoleBean() {
return this.role;
}

public void setRoleBean(RoleBean role) {
this.role = role;
}

public String getUsername() {
return this.username;
}

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

public String getPassword() {
return this.password;
}

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

public Date getBirth() {
return birth;
}

public void setBirth(Date birth) {
this.birth = birth;
}

public Boolean getSex() {
return this.sex;
}

public void setSex(Boolean sex) {
this.sex = sex;
}

public String getRepassword() {
return repassword;
}

public void setRepassword(String repassword) {
this.repassword = repassword;
}

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

前台页面:

　　index.jsp：　　

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib uri="http://www.springframework.org/tags/form" prefix="form"%>
<%@ taglib uri="http://java.sun.com/jstl/core" prefix="c" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>${initParam.appName }</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
</head>
<body>
<a href="login.do">登录系统</a>
</body>
</html>

　　login.jsp:

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib uri="http://www.springframework.org/tags/form" prefix="form"%>
<%@ taglib uri="http://java.sun.com/jstl/core" prefix="c" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>${initParam.appName }</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
</head>
<body>
<form:form modelAttribute="user" >
<table>
<tr>
<td><form:label path="username">用户名称：</form:label></td>
<td><form:input path="username" cssStyle="width=200px"/><form:errors path="username"/></td>
</tr>
<tr>
<td><form:label path="password">用户口令：</form:label></td>
<td><form:password path="password" cssStyle="width=200px"/><form:errors path="password"/></td>
</tr>
<tr>
<td colspan="2">
<input type="submit" value="登录系统">
<input type="reset" value="重置数据">
</td>
</tr>
</table>
</form:form>
</body>
</html>

　　show.jsp:　　

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib uri="http://www.springframework.org/tags/form" prefix="form"%>
<%@ taglib uri="http://java.sun.com/jstl/core" prefix="c" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>${initParam.appName }</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
</head>
<body>
登陆成功...
</body>
</html>

效果图: