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>*.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: