SSM 小demo（很详细，适合新手）

自己做了一个基于SSM框架的小项目，跟大家分享一下..

首先，你需要开发工具netbeans或者eclipse一枚，我习惯用netbeans,这个随意，mysql数据库，

此为前提条件，因为是小项目，所以需求分析和用例图暂免了吧，有兴趣可以画。下面正式开始

先看一下大概的项目分层

看一眼jar包及JSP页面

我习惯先于数据库下手，然后映射数据库和pojo类，然后配置文件，然后dao->service层，控制器和jsp页面看需求

1）创建一个 student_clazz表，也就是学生-教室-老师表，涉及表与表之间的关系，老师与学生之间为多对多的关系，即一个学生有多个老师，化学啦生物啦，一个老师也有很多学生；教室与学生之间为一对多的关系，即一间教室有多位学生（假定在这个教室的这些学生只在这一个教室上课），人物关系介绍完毕~

至于主外键，为数据库基础不再赘述

CREATE DATABASE student_clazzUSE student_clazzCREATE TABLE Clazz(C_Id INT PRIMARY KEY NOT NULL,C_Address VARCHAR(20));INSERT INTO Clazz VALUES(1,'博知');INSERT INTO Clazz VALUES(2,'静思');INSERT INTO Clazz VALUES(3,'博文');INSERT INTO Clazz VALUES(4,'博学');CREATE TABLE Student(S_Id INT PRIMARY KEY NOT NULL,S_Name VARCHAR(20),S_Gender VARCHAR(20),S_Age VARCHAR(20),clazz_id INT,FOREIGN KEY (clazz_id) REFERENCES Clazz(C_Id));INSERT INTO Student VALUES(10111,'anna','女','18',2);INSERT INTO Student VALUES(10222,'juin','男','12',1);INSERT INTO Student VALUES(10333,'edwina','女','11',1);INSERT INTO Student VALUES(10444,'david','男','14',2);CREATE TABLE Teacher(T_Id INT PRIMARY KEY NOT NULL,T_Name VARCHAR(20) NOT NULL,T_Type VARCHAR(20) NOT NULL,T_Gender VARCHAR(20) NOT NULL,T_Age VARCHAR(20) NOT NULL,T_Mobile INT);INSERT INTO Teacher VALUES(2201,'里番番','数学','女','21',279376);INSERT INTO Teacher VALUES(22002,'大卫','语文','男','22',279326);INSERT INTO Teacher VALUES(22003,'卡瑟琳','英语','女','23',279326);INSERT INTO Teacher VALUES(22004,'鲁迅','NIIT','男','24',279326);CREATE TABLE ItemOne(student_id INT,teacher_id INT,PRIMARY KEY(student_id,teacher_id),FOREIGN KEY(student_id) REFERENCES Student(S_Id),FOREIGN KEY(teacher_id) REFERENCES Teacher(T_Id));INSERT INTO ItemOne VALUES(20111,22003);INSERT INTO ItemOne VALUES(20111,2201);INSERT INTO ItemOne VALUES(20111,22002);INSERT INTO ItemOne VALUES(30332,22004);INSERT INTO ItemOne VALUES(30332,22002);INSERT INTO ItemOne VALUES(20221,22003);INSERT INTO ItemOne VALUES(20221,22004);

2）再做pojo类和数据库的映射

先建三个pojo类，有人问为什么要继承Serializable，其实我们在自己电脑上做程序的时候可以不用写，
它可以把对象转换成字节流在网络上传输，如果你不写自然没法传输，那程序也就没法使用
然后挨个写映射文件，这个对数据库的熟练还是有点要求的，增删改查相关操作都写在映射文件里，

association是用来映射一对一的关系及多对一的关系，collection用来映射一对多和多对多的关系，具体

方法如下

（和hibernate的区别参考上一篇博文。这些增删改查的语句的引用都在dao包的实现类里，通过sqlSession

提供的方法具体操作。）

1>Clazz

public class Clazz implements Serializable {    private int clazzId;    private String clazzAddress;    private List<Student> students;    public int getClazzId() {        return clazzId;    }    public void setClazzId(int clazzId) {        this.clazzId = clazzId;    }    public String getClazzAddress() {        return clazzAddress;    }    public void setClazzAddress(String clazzAddress) {        this.clazzAddress = clazzAddress;    }    public List<Student> getStudents() {        return students;    }    public void setStudents(List<Student> students) {        this.students = students;    }    @Override    public String toString() {        return "Clazz{" + "clazzId=" + clazzId + ", clazzAddress=" + clazzAddress + ", students=" + students + '}';    }}

，与它匹配的映射文件

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"><mapper namespace="com.qdu.mapping.ClazzMapper">    <select id="selectClazzById" resultMap="ClazzResultMap" parameterType="int">        select * from Clazz where C_Id= #{clazzId}    </select>    <resultMap id="ClazzResultMap" type="com.qdu.pojo.Clazz">        <id property="clazzId" column="C_Id"/>        <result property="clazzAddress" column="C_Address"/>                    <!--下面有个column是“C_Id”，我个人的理解是这个为当前表的主键做了另一个表的外键，起到一个关联作用,这是提供给另一个表的-->        <collection property="students" javaType="ArrayList" column="C_Id" ofType="com.qdu.pojo.Student"                    select="com.qdu.mapping.StudentMapper.selectStudentByClazzId">            <id property="stuId" column="S_Id"/>            <result property="stuName" column="S_Name"/>            <result property="stuGender" column="S_Gender"/>            <result property="stuAge" column="S_Age"/>        </collection>    </resultMap></mapper>

2>Student

public class Student implements Serializable{    private int stuId;    private String stuName;    private String stuGender;    private String stuAge;    private Clazz clazz;    private List<Teacher> teachers;    public int getStuId() {        return stuId;    }    public void setStuId(int stuId) {        this.stuId = stuId;    }    public String getStuName() {        return stuName;    }    public void setStuName(String stuName) {        this.stuName = stuName;    }    public String getStuGender() {        return stuGender;    }    public void setStuGender(String stuGender) {        this.stuGender = stuGender;    }    public String getStuAge() {        return stuAge;    }    public void setStuAge(String stuAge) {        this.stuAge = stuAge;    }    public Clazz getClazz() {        return clazz;    }    public void setClazz(Clazz clazz) {        this.clazz = clazz;    }    public List<Teacher> getTeachers() {        return teachers;    }    public void setTeachers(List<Teacher> teachers) {        this.teachers = teachers;    }    @Override    public String toString() {        return "Student{" + "stuId=" + stuId + ", stuName=" + stuName + ", stuGender=" + stuGender + ", stuAge=" + stuAge + ", clazz=" + clazz + ", teachers=" + teachers + '}';    }}

，Student的映射文件为

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"><mapper namespace="com.qdu.mapping.StudentMapper">        <!--之所以会用到两个表我认为是因为在数据库中Student表中引用了clazz-->    <select id="selectStudentById" resultMap="StudentResultMap" parameterType="int">        select * from Student s,Clazz c        where s.clazz_id = c.C_Id         And s.S_id = #{stuId}    </select>        <select id="selectStudentByClazzId" resultMap="StudentResultMap" parameterType="int">        select * from Student where clazz_id = #{C_id}    </select>            <select id="selectStudentByTeacherId" resultMap="StudentResultMap" parameterType="int">        select * from Student where S_Id in (        select student_id from ItemOne where teacher_id = #{T_Id}         )    </select>        <insert id="insertStudent" parameterType="com.qdu.pojo.Student">        INSERT INTO Student(S_Id,S_Name,S_Gender,S_Age,clazz_id) VALUES (#{stuId},#{stuName},#{stuGender},#{stuAge},#{clazz.clazzId});    </insert>        <update id="updateStudent" parameterType="com.qdu.pojo.Student" statementType="PREPARED">        update Student set        S_Name=#{stuName},        S_Gender=#{stuGender},        S_Age=#{stuAge},        clazz_id=#{clazz.clazzId}        where S_Id = #{stuId}    </update>        <delete id="deleteStudentById" parameterType="com.qdu.pojo.Student">        delete from Student where S_Id = #{stuId}    </delete>        <resultMap id="StudentResultMap" type="com.qdu.pojo.Student">        <id property="stuId" column="S_Id"/>        <result property="stuName" column="S_Name"/>        <result property="stuGender" column="S_Gender"/>        <result property="stuAge" column="S_Age"/>        <!--多对一-->        <association property="clazz" javaType="com.qdu.pojo.Clazz">            <id property="clazzId" column="C_Id"/>            <result property="clazzAddress" column="C_Address"/>        </association>        <!--多对多-->        <collection property="teachers" javaType="ArrayList" column="S_Id" ofType="com.qdu.pojo.Teacher"                     select="com.qdu.mapping.TeacherMapper.selectTeacherByStudentId">            <id property="teacherId" column="T_Id"/>            <result property="teacherName" column="T_Name"/>            <result property="teacherType" column="T_Type"/>            <result property="teacherGender" column="T_Gender"/>            <result property="teacherAge" column="T_Age"/>            <result property="teacherMobile" column="T_Mobile"/>        </collection>    </resultMap></mapper>

3>Teacher

public class Teacher implements Serializable {    private int teacherId;    private String teacherName;    private String teacherType;    private String teacherGender;    private String teacherAge;    private int teacherMobile;    private List<Student> students;    public int getTeacherId() {        return teacherId;    }    public void setTeacherId(int teacherId) {        this.teacherId = teacherId;    }    public String getTeacherName() {        return teacherName;    }    public void setTeacherName(String teacherName) {        this.teacherName = teacherName;    }    public String getTeacherType() {        return teacherType;    }    public void setTeacherType(String teacherType) {        this.teacherType = teacherType;    }    public String getTeacherGender() {        return teacherGender;    }    public void setTeacherGender(String teacherGender) {        this.teacherGender = teacherGender;    }    public String getTeacherAge() {        return teacherAge;    }    public void setTeacherAge(String teacherAge) {        this.teacherAge = teacherAge;    }    public int getTeacherMobile() {        return teacherMobile;    }    public void setTeacherMobile(int teacherMobile) {        this.teacherMobile = teacherMobile;    }    public List<Student> getStudents() {        return students;    }    public void setStudents(List<Student> students) {        this.students = students;    }}

，映射文件为

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"><mapper namespace="com.qdu.mapping.StudentMapper">        <!--之所以会用到两个表我认为是因为在数据库中Student表中引用了clazz-->    <select id="selectStudentById" resultMap="StudentResultMap" parameterType="int">        select * from Student s,Clazz c        where s.clazz_id = c.C_Id         And s.S_id = #{stuId}    </select>        <select id="selectStudentByClazzId" resultMap="StudentResultMap" parameterType="int">        select * from Student where clazz_id = #{C_id}    </select>            <select id="selectStudentByTeacherId" resultMap="StudentResultMap" parameterType="int">        select * from Student where S_Id in (        select student_id from ItemOne where teacher_id = #{T_Id}         )    </select>        <insert id="insertStudent" parameterType="com.qdu.pojo.Student">        INSERT INTO Student(S_Id,S_Name,S_Gender,S_Age,clazz_id) VALUES (#{stuId},#{stuName},#{stuGender},#{stuAge},#{clazz.clazzId});    </insert>        <update id="updateStudent" parameterType="com.qdu.pojo.Student" statementType="PREPARED">        update Student set        S_Name=#{stuName},        S_Gender=#{stuGender},        S_Age=#{stuAge},        clazz_id=#{clazz.clazzId}        where S_Id = #{stuId}    </update>        <delete id="deleteStudentById" parameterType="com.qdu.pojo.Student">        delete from Student where S_Id = #{stuId}    </delete>        <resultMap id="StudentResultMap" type="com.qdu.pojo.Student">        <id property="stuId" column="S_Id"/>        <result property="stuName" column="S_Name"/>        <result property="stuGender" column="S_Gender"/>        <result property="stuAge" column="S_Age"/>        <!--多对一-->        <association property="clazz" javaType="com.qdu.pojo.Clazz">            <id property="clazzId" column="C_Id"/>            <result property="clazzAddress" column="C_Address"/>        </association>        <!--多对多-->        <collection property="teachers" javaType="ArrayList" column="S_Id" ofType="com.qdu.pojo.Teacher"                     select="com.qdu.mapping.TeacherMapper.selectTeacherByStudentId">            <id property="teacherId" column="T_Id"/>            <result property="teacherName" column="T_Name"/>            <result property="teacherType" column="T_Type"/>            <result property="teacherGender" column="T_Gender"/>            <result property="teacherAge" column="T_Age"/>            <result property="teacherMobile" column="T_Mobile"/>        </collection>    </resultMap></mapper>

3）接下来就是配置文件，重头戏

配置文件分为Spring-mybatis配置文件和Spring MVC配置文件

Spring-mybatis配置文件的作用就是作为持久层框架起一个水渠的作用。

<?xml version='1.0' encoding='UTF-8' ?><!-- was: <?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:p="http://www.springframework.org/schema/p"       xmlns:aop="http://www.springframework.org/schema/aop"       xmlns:tx="http://www.springframework.org/schema/tx"       xmlns:context="http://www.springframework.org/schema/context"              xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd       http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd       http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd       http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd" >    <context:component-scan base-package="com.qdu"/>            <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">         <property name="driverClassName" value="com.mysql.jdbc.Driver" />        <property name="url" value="jdbc:mysql://localhost:3306/student_clazz" />        <property name="username" value="sa" />        <property name="password" value="niit" />    </bean>    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">        <property name="dataSource" ref="dataSource"/>        <property name="mapperLocations" value="classpath:com/qdu/mapping/*.xml"/>    </bean>    <bean id="txManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">        <property name="dataSource" ref="dataSource"/>    </bean>        <tx:annotation-driven transaction-manager="txManager"/>    </beans>

Spring MVC配置文件作为请求分发器用来分发请求到制定的控制器

<?xml version='1.0' encoding='UTF-8' ?><!-- was: <?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:p="http://www.springframework.org/schema/p"       xmlns:aop="http://www.springframework.org/schema/aop"       xmlns:tx="http://www.springframework.org/schema/tx"       xmlns:mvc="http://www.springframework.org/schema/mvc"       xmlns:context="http://www.springframework.org/schema/context"              xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd       http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd       http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd       http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd       http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd">    <context:component-scan base-package="com.qdu.controller"/>    <mvc:annotation-driven/>    <mvc:default-servlet-handler/>               <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"          id="internalResourceViewResolver">        <!-- 前缀 -->        <property name="prefix" value="/WEB-INF/jsp/"/>        <!-- 后缀 -->        <property name="suffix" value=".jsp" />    </bean></beans>

4）再就是配置web.xml了，把两个配置文件向项目向程序说明一下

<?xml version="1.0" encoding="UTF-8"?><web-app version="3.1" 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_3_1.xsd">    <context-param>        <param-name>contextConfigLocation</param-name>        <param-value>/WEB-INF/applicationContext.xml</param-value>    </context-param>    <listener>        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>    </listener>            <servlet>        <servlet-name>dispatcher</servlet-name>        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class><!--         <init-param>            Servlet范围内的参数            <param-name>contextConfigLocation</param-name>            <param-value>classpath:dispatcher-servlet.xml</param-value>        </init-param>-->        <load-on-startup>1</load-on-startup>    </servlet>    <servlet-mapping>        <servlet-name>dispatcher</servlet-name>        <url-pattern>*.do</url-pattern>    </servlet-mapping>                <session-config>        <session-timeout>            30        </session-timeout>    </session-config>    <welcome-file-list>        <welcome-file>index.jsp</welcome-file>    </welcome-file-list></web-app>

5）我习惯dao和service都写接口再实现，这是个好习惯，符合框架低耦合的观念，这次例外，dao接口没写，

可以自己补上。

@Repository用于标注数据访问组件,即DAO组件

statement为mapper文件中的具体的sql语句

@Repositorypublic class StudentDao {    @Autowired    private SqlSessionFactory sqlSessionFactory;        public List studentList(int clazzId){        String statement="com.qdu.mapping.StudentMapper.selectStudentByClazzId";        return sqlSessionFactory.openSession().selectList(statement, clazzId);    }    public List selectTeacherByStudentId(int stuId){        String statement = "com.qdu.mapping.TeacherMapper.selectTeacherByStudentId";        return sqlSessionFactory.openSession().selectList(statement, stuId);    }        public Student selectStudentById(int stuId) {        String statement = "com.qdu.mapping.StudentMapper.selectStudentById";        System.out.println(sqlSessionFactory);        return sqlSessionFactory.openSession().selectOne(statement, stuId);    }     public Clazz selectClazzById(int clazzId) {        String statement = "com.qdu.mapping.ClazzMapper.selectClazzById";        return sqlSessionFactory.openSession().selectOne(statement, clazzId);    }     public void insertStudent(Student student){         String statement="com.qdu.mapping.StudentMapper.insertStudent";         sqlSessionFactory.openSession().insert(statement, student);     }          public void updateStudent(Student student){         String statement="com.qdu.mapping.StudentMapper.updateStudent";         sqlSessionFactory.openSession().update(statement, student);     }          public void deleteStudent(int stuId){         String statement="com.qdu.mapping.StudentMapper.deleteStudentById";         sqlSessionFactory.openSession().delete(statement, stuId);     }          public Teacher selectTeacherById(int teacherId){         String statement="com.qdu.mapping.TeacherMapper.selectTeacherById";        return sqlSessionFactory.openSession().selectOne(statement,teacherId);     }          }

Service接口：

public interface StudentService {    public Student getStudentById(int stuId);    public List selectTeacherByStudentId(int stuId);    public Clazz getClazzById(int clazzId);    public void insertStudent(Student student);    public void updateStudent(Student student);    public void deleteStudent(int stuId);    public List studentList(int clazzId);    public Teacher selectTeacherById(int teacherId);}

@Transactional为Spring的事务注解,表示该类里面的所有方法或者这个方法的事务由spring处理,
来保证事务的原子性, 每一个业务方法开始时都会打开一个事务,这样的好处，可以省去一些XML
配置文件的繁琐编写
@Transactional 注解应该只被应用到 public 方法上，这是由 Spring AOP 的本质决定的。如果你在 protected、private 或者默认可见性的方法上使用 @Transactional 注解，这将被忽略，也不会抛出任何异常。


默认情况下，只有来自外部的方法调用才会被AOP代理捕获，也就是，类内部方法调用本类内部的其他方法并不会引起事务行为，即使被调用方法使用@Transactional注解进行修饰。


事务管理对于企业应用来说是至关重要的，即使出现异常情况，它也可以保证数据的一致性


@Service为Spring的service注解，标注服务类

//为什么要用接口？！//第一种方式：建立个接口//第二种方式：直接实例化//第一种：比如你用Spring框架，可以在用到UserServiceImpl的时候定义接口，最后使用XML方式实例化，这样以后需要修改，只要改xml(所谓的低耦合)//第二种：假设你直接在java文件中直接实例化，万一你不在用这个类了，要用另外的类来代替，需要改java文件，很麻烦（即所谓的低内聚高耦合）//耦合度低的程序要好@Transactional@Service("studentServiceImpl")public class StudentServiceImpl implements StudentService {    @Autowired    private StudentDao studentDao;    @Override    public Student getStudentById(int stuId) {//        System.out.println(studentDao.selectStudentById(10111));        return studentDao.selectStudentById(stuId);    }    @Override    public Clazz getClazzById(int clazzId) {        System.out.println(studentDao.selectClazzById(1));        return studentDao.selectClazzById(clazzId);    }    @Override    public void insertStudent(Student student) {        studentDao.insertStudent(student);    }    @Override    public void updateStudent(Student student) {        studentDao.updateStudent(student);    }    @Override    public void deleteStudent(int stuId) {        studentDao.deleteStudent(stuId);    }    @Override    public List studentList(int clazzId) {      return studentDao.studentList(clazzId);    }    @Override    public List selectTeacherByStudentId(int stuId) {        return studentDao.selectTeacherByStudentId(stuId);    }    @Override    public Teacher selectTeacherById(int teacherId) {        return studentDao.selectTeacherById(teacherId);    }}

@Controller控制器注解，用于处理多个URL请求@RequestMapping 可以标注在类定义处，将 Controller 和特定请求关联起来；还可以标注在方法签名处，以便进一步对请求进行分流

@Controller@RequestMapping(value = "/anna")public class TestController {    @Autowired    private StudentService studentServiceImpl;//调用父类的方法，再调用子类中的方法    @RequestMapping(value = "/student.do")    public String studentLogin(ModelMap map) {        return "student";    }    @RequestMapping(value = "/admin.do")    public String teacherLogin(ModelMap map) {        return "admin";    }    @RequestMapping(value = "/juin.do")    public String queryStudent(HttpServletRequest request, ModelMap map) {        int id = Integer.parseInt(request.getParameter("stuId"));        int password = Integer.parseInt(request.getParameter("password"));        Student student = studentServiceImpl.getStudentById(id);        System.out.println(student);//        int转String验证可以＋""啊        if (student != null && (id + "") != null && (password + "") != null && id == student.getStuId() && password == 123) {            map.addAttribute("student", student);            return "success";        } else {            return "fail";        }    }    @RequestMapping(value = "/adminLogin.do")    public String teacherLoginDo(HttpServletRequest request, ModelMap map) {        int id = Integer.parseInt(request.getParameter("id"));        int password = Integer.parseInt(request.getParameter("password"));        Clazz clazz = studentServiceImpl.getClazzById(id);        if (id == clazz.getClazzId() && password == 123) {            map.addAttribute("clazz", clazz);            return "adminSuccess";        } else {            return "fail";        }    }    @RequestMapping(value = "forInsertStudent.do")    public String forInsertStudent(ModelMap map, int clazzId, HttpServletRequest request) {        clazzId = Integer.parseInt(request.getParameter("clazzId"));        Clazz clazz = studentServiceImpl.getClazzById(clazzId);                Date time = new Date(System.currentTimeMillis());        SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd");        String current = sdf.format(time);        Random random = new Random();        int cc=Integer.parseInt(current);        int x = random.nextInt(900) + 100;        System.out.println(cc);                map.addAttribute("clazz", clazz);        map.addAttribute("date", cc);        map.addAttribute("random", x);        return "insertStudent";    }    @RequestMapping(value = "insertStudent.do")    public String insertStudent(HttpServletRequest request, ModelMap map, Student student) {        studentServiceImpl.insertStudent(student);        int id = Integer.parseInt(request.getParameter("clazz.clazzId"));        Clazz clazz = studentServiceImpl.getClazzById(id);        map.addAttribute("clazz", clazz);        return "adminSuccess";    }    @RequestMapping(value = "forUpdateStudent.do")    public String forUpdateStudent(HttpServletRequest request, ModelMap map) {        int id = Integer.parseInt(request.getParameter("stuId"));        Student student = studentServiceImpl.getStudentById(id);        map.addAttribute("student", student);        return "updateStudent";    }    @RequestMapping(value = "updateStudent.do")    public String updateStudent(ModelMap map, Student student, int stuId) {        studentServiceImpl.updateStudent(student);        student = studentServiceImpl.getStudentById(stuId);        Clazz clazz = studentServiceImpl.getClazzById(student.getClazz().getClazzId());        map.addAttribute("clazz", clazz);        return "adminSuccess";    }    @RequestMapping(value = "forDeleteStudent.do")    public String forDeleteStudent(HttpServletRequest request, ModelMap map) {        int id = Integer.parseInt(request.getParameter("stuId"));        Student student = studentServiceImpl.getStudentById(id);        map.addAttribute("student", student);        return "deleteStudent";    }//    clazzId来源于前端的传值，免去request，是不是很有趣？另外，逻辑语句要有先有后，第n次逻辑颠倒    @RequestMapping(value = "deleteStudent.do")    public String deleteStudent(ModelMap map, int clazzId, int stuId, Student student, Clazz clazz) {        studentServiceImpl.deleteStudent(stuId);        clazz = studentServiceImpl.getClazzById(clazzId);        map.addAttribute("clazz", clazz);        return "adminSuccess";    }    @RequestMapping(value = "teacher.do")    public String teacher() {        return "teacher";    }    @RequestMapping(value = "teacherLogin.do")    public String teacherLogin(ModelMap map, HttpServletRequest request) {        int teacherId = Integer.parseInt(request.getParameter("teacherId"));        int password = Integer.parseInt(request.getParameter("password"));        Teacher teacher = studentServiceImpl.selectTeacherById(teacherId);        if (teacherId == teacher.getTeacherId() && password == 123) {//                for (int i = 0; i < teacher.getStudents().size(); i++) {//                Student student = studentServiceImpl.getStudentById(teacher.getStudents().get(i).getStuId());            map.addAttribute("teacher", teacher);//                map.addAttribute("sss", student);//                }            return "teacherSuccess";        } else {            return "fail";        }    }    @RequestMapping(value = "firstPage.do")    public String firstPage() {        return "translate";    }}

最后就是页面了，JSP页面与JSTL以及EL表达式相结合，足够满足一般需求

页面很多，贴出最主要的一两个

首页

不同身份登录

<%@page contentType="text/html" pageEncoding="UTF-8"%><!DOCTYPE html><html>    <head>        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">        <title>首页</title>    </head>    <body>        <form>        <h2>登录身份选择</h2>        <a href="anna/student.do">Student</a>        <a href="anna/teacher.do">Teacher</a>        <a href="anna/admin.do">Admin</a>        </form>    </body></html>

教师登录

<%--     Document   : teacher    Created on : 2017-4-27, 16:50:03    Author     : ACER--%><%@page contentType="text/html" pageEncoding="UTF-8"%><!DOCTYPE html><html>    <head>        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">        <title>教师登录</title>    </head>    <body>        <form action="teacherLogin.do">            教师账号: <input type="text" name="teacherId" placeholder="在此输入账号"/><br/><br/>           教师密码: <input type="password" name="password" placeholder="在此输入密码"/><br/><br/>            <input type="submit" value="提交"/>        </form>    </body></html>

登录成功页面

<%--     Document   : teacherSuccess    Created on : 2017-4-27, 17:59:20    Author     : ACER--%><%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %><%@page contentType="text/html" pageEncoding="UTF-8"%><!DOCTYPE html><html>    <head>        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">        <title>教师登录成功</title>    </head>    <body>        <h2>登录成功-<code style="color: #00CC00">${teacher.teacherName}</code>老师</h2>        <table border="2">            <caption>学生列表</caption>            <tr>                <th>学生Id</th>                <th>学生姓名</th>                <th>学生性别</th>                <th>学生年龄</th>                <!--<th>学生教室</th>-->            </tr>            <c:forEach items="${teacher.students}" var="s">                <tr id="${s.stuId}" >                    <td>${s.stuId}</td>                    <td>${s.stuName}</td>                    <td>${s.stuGender}</td>                    <td>${s.stuAge}</td>                   </tr>            </c:forEach>        </table>    </body></html>

运行结果

         此为结束，欢迎大家提出问题，共同探讨

                                                                                 ____Juin