【Spring从入门到实战教程】第七章 Spring 整合Web项目

﹏ヽ暗。殇╰゛Y 2024-04-28 13:22 70阅读 0赞

## 七、Spring 整合Web项目 ##

### 7.1 整合思路 ###

**目前为止，每次获取对象，都必须先创建IOC容器，操作如下：**

ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");

但这种操作如果放在一个项目中效率太低，IOC容器的初始化工作应该是提前准备好，并且是一次性的。在Web项目中，把加载Spring配置文件和创建IOC容器的过程，放在服务器启动时候完成。

实现思路如下：  
1、在服务器启动时，为每个项目创建一个ServletContext对象；  
2、使用监听器，监听ServletContext对象的创建；  
3、监听器监听到ServletContext创建时候，加载Spring核心配置文件；  
4、把IOC容器存放到SetvletContext域对象中；  
5、需要获取对象时，从ServletContext域取出IOC容器；

### 7.2. 实现步骤 ###

#### 7.2.1 引入maven依赖 ####

<dependencies>
        
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
            <scope>provided</scope>
        </dependency>
        
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.1</version>
            <scope>provided</scope>
        </dependency>
        
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>
    
        
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>4.3.18.RELEASE</version>
        </dependency>
        
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>4.3.18.RELEASE</version>
        </dependency>
        
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>4.3.18.RELEASE</version>
        </dependency>
        
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-expression</artifactId>
            <version>4.3.18.RELEASE</version>
        </dependency>
        
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aop</artifactId>
            <version>4.3.18.RELEASE</version>
        </dependency>
        
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aspects</artifactId>
            <version>4.3.18.RELEASE</version>
        </dependency>
        
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>4.3.18.RELEASE</version>
        </dependency>
        
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>4.3.18.RELEASE</version>
        </dependency>
        
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-tx</artifactId>
            <version>4.3.18.RELEASE</version>
        </dependency>
        
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.49</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

#### 7.2.2 监听器的实现 ####

@WebListener
    public class SpringContextListener implements ServletContextListener {
        @Override
        public void contextInitialized(ServletContextEvent servletContextEvent) {
            /**
             * 在web项目中的上下对象创建之后，将spring的IOC容器放置在上下文对象
             */
            //1.获取上下文对象
            ServletContext sc = servletContextEvent.getServletContext();
            //2.创建IOC容器
            ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
            //3.将容器对象放入到上下文域中
            sc.setAttribute("ac", ac);
        }
    
        @Override
        public void contextDestroyed(ServletContextEvent servletContextEvent) {
    
        }
    }

#### 7.2.3 Bean对象 ####

@Component
    public class Person {
        @Value("101")
        private Integer id;
        @Value("小明")
        private String name;
    
        public Integer getId() {
            return id;
        }
    
        public void setId(Integer id) {
            this.id = id;
        }
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
        @Override
        public String toString() {
            return "Person{" +
                    "id=" + id +
                    ", name='" + name + '\'' +
                    '}';
        }
    }

#### 7.2.4 applicationContext.xml ####

#### 7.2.5 Servlet ####

@WebServlet("/getPerson")
    public class PersonServlet extends HttpServlet {
        @Override
        protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
            doPost(req, resp);
        }
    
        @Override
        protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    
            //1.取出容器
            ApplicationContext ac = (ApplicationContext) this.getServletContext().getAttribute("ac");
    
            //2.容器中获取对象
            Person person = ac.getBean("person", Person.class);
    
            System.out.println(person.getId() + "---" + person.getName());
        }
    }

#### 7.2.6 web.xml ####

### 7.3 Spring中的实现 ###

在Spring中已经实现了初始化IOC容器的监听器，需要导入Spring整合web项目的jar包。

**web.xml：**

<?xml version="1.0" encoding="UTF-8"?>
    <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">
        
        
        
        <context-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:applicationContext.xml</param-value>
        </context-param>
        <listener>
            <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
        </listener>
    </web-app>

**Spring在Web项目中使用的容器为：WebApplicationContext**

//从上下文对象中获取IOC容器对象
    WebApplicationContext ac = WebApplicationContextUtils.getWebApplicationContext(this.getServletContext());
    
    Person person = ac.getBean("person", Person.class);
    System.out.println(person.getId() + "---" + person.getName());

### 7.4 Web项目的完整实现 ###

#### 7.4.1 applicationContext.xml ####

**db.properties：**

# Oracle相关配置
    jdbc.oracle.driver=oracle.jdbc.driver.OracleDriver
    jdbc.oracle.url=jdbc:oracle:thin:@localhost:1521:orcl
    jdbc.oracle.username=scott
    jdbc.oracle.password=tiger
    
    # Mysql相关配置
    jdbc.mysql.driver=com.mysql.jdbc.Driver
    jdbc.mysql.url=jdbc:mysql://localhost:3306/ssm?characterEncoding=utf8&useSSL=false
    jdbc.mysql.username=root
    jdbc.mysql.password=root

<?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:util="http://www.springframework.org/schema/util"
            xmlns:p="http://www.springframework.org/schema/p"
            xmlns:context="http://www.springframework.org/schema/context"
            xmlns:aop="http://www.springframework.org/schema/aop"
            xmlns:tx="http://www.springframework.org/schema/tx"
            xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/util
        http://www.springframework.org/schema/util/spring-util.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/aop
        http://www.springframework.org/schema/aop/spring-aop.xsd
        http://www.springframework.org/schema/tx
        http://www.springframework.org/schema/tx/spring-tx.xsd">
    
        
        <context:component-scan base-package="com.newcapec"/>
    
        
        <context:property-placeholder location="classpath:db.properties"/>
    
        <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
            <property name="driverClassName" value="${jdbc.mysql.driver}"/>
            <property name="url" value="${jdbc.mysql.url}"/>
            <property name="username" value="${jdbc.mysql.username}"/>
            <property name="password" value="${jdbc.mysql.password}"/>
        </bean>
    
        
        <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
            <property name="dataSource" ref="dataSource"/>
        </bean>
    
    </beans>

**web.xml：**

#### 7.4.2 实体类 ####

@Component
    public class Student {
    
        private Integer id;
        private String name;
        private Integer age;
        private String major;
    
        public Integer getId() {
            return id;
        }
    
        public void setId(Integer id) {
            this.id = id;
        }
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
        public Integer getAge() {
            return age;
        }
    
        public void setAge(Integer age) {
            this.age = age;
        }
    
        public String getMajor() {
            return major;
        }
    
        public void setMajor(String major) {
            this.major = major;
        }
    
        @Override
        public String toString() {
            return "Student{" +
                    "id=" + id +
                    ", name='" + name + '\'' +
                    ", age=" + age +
                    ", major='" + major + '\'' +
                    '}';
        }
    }

#### 7.4.3 Dao ####

**sql语句：**

CREATE TABLE `t_student`  (
      `id` int(11) NOT NULL AUTO_INCREMENT COMMENT '学生id',
      `name` varchar(20) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '学生姓名',
      `age` int(2) NULL DEFAULT NULL COMMENT '学生性别',
      `major` varchar(20) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '学生专业',
      PRIMARY KEY (`id`) USING BTREE
    ) ENGINE = InnoDB AUTO_INCREMENT = 5 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Compact;
    
    -- ----------------------------
    -- Records of t_student
    -- ----------------------------
    INSERT INTO `t_student` VALUES (2, '小红', 1, '网络工程');
    INSERT INTO `t_student` VALUES (3, 'tom', 12, '计算机');
    INSERT INTO `t_student` VALUES (4, '曹操', 12, '挖墓');
    
    SET FOREIGN_KEY_CHECKS = 1;

**接口：**

public interface StudentDao {
        void insertStudent(Student student);
    
        void updateStudent(Student student);
    
        void deleteStudent(Integer id);
    
        Student selectStudentById(Integer id);
    
        List<Student> selectStudent();
    }

**实现类：**

@Repository("studentDao")
    public class StudentDaoImpl implements StudentDao {
    
        @Autowired
        private JdbcTemplate jdbcTemplate;
    
        @Override
        public void insertStudent(Student student) {
            //String sql = "insert into t_student(id,name,age,major) values(seq_demo.nextval,?,?,?)";
            String sql = "insert into t_student(name,age,major) values(?,?,?)";
            jdbcTemplate.update(sql, student.getName(), student.getAge(), student.getMajor());
        }
    
        @Override
        public void updateStudent(Student student) {
            String sql = "update t_student set name=?,age=?,major=? where id=?";
            jdbcTemplate.update(sql, student.getName(), student.getAge(), student.getMajor(), student.getId());
        }
    
        @Override
        public void deleteStudent(Integer id) {
            String sql = "delete from t_student where id=?";
            jdbcTemplate.update(sql, id);
        }
    
        @Override
        public Student selectStudentById(Integer id) {
            String sql = "select id,name,age,major from t_student where id=?";
            RowMapper<Student> rowMapper = new BeanPropertyRowMapper<>(Student.class);
            return jdbcTemplate.queryForObject(sql, rowMapper, id);
        }
    
        @Override
        public List<Student> selectStudent() {
            String sql = "select id,name,age,major from t_student order by id desc";
            RowMapper<Student> rowMapper = new BeanPropertyRowMapper<>(Student.class);
            return jdbcTemplate.query(sql, rowMapper);
        }
    }

#### 7.4.3 Service ####

**接口：**

public interface StudentService {
        void addStudent(Student student);
    
        void editStudent(Student student);
    
        void removeStudent(Integer id);
    
        Student findStudentById(Integer id);
    
        List<Student> findStudent();
    }

**实现类：**

@Service("studentService")
    public class StudentServiceImpl implements StudentService {
    
        @Autowired
        private StudentDao studentDao;
    
        @Override
        public void addStudent(Student student) {
            studentDao.insertStudent(student);
        }
    
        @Override
        public void editStudent(Student student) {
            studentDao.updateStudent(student);
        }
    
        @Override
        public void removeStudent(Integer id) {
            studentDao.deleteStudent(id);
        }
    
        @Override
        public Student findStudentById(Integer id) {
            return studentDao.selectStudentById(id);
        }
    
        @Override
        public List<Student> findStudent() {
            return studentDao.selectStudent();
        }
    }

#### 7.4.4 Servlet ####

@WebServlet({"/findStudent", "/addStudent", "/editStudent", "/removeStudent", "/getStudent"})
    public class StudentServlet extends HttpServlet {
        @Override
        protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
            doPost(req, resp);
        }
    
        @Override
        protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    
            WebApplicationContext ac = WebApplicationContextUtils.getWebApplicationContext(this.getServletContext());
            StudentService studentService = ac.getBean("studentService", StudentService.class);
    
            String path = req.getServletPath();
            if (path.contains("find")) {
                List<Student> list = studentService.findStudent();
                req.setAttribute("list", list);
                req.getRequestDispatcher("/student.jsp").forward(req, resp);
            } else if (path.contains("add")) {
                String name = req.getParameter("name");
                String age = req.getParameter("age");
                String major = req.getParameter("major");
                Student student = new Student();
                student.setName(name);
                student.setAge(Integer.parseInt(age));
                student.setMajor(major);
                studentService.addStudent(student);
                req.getRequestDispatcher("/findStudent").forward(req, resp);
            } else if (path.contains("edit")) {
                String id = req.getParameter("id");
                String name = req.getParameter("name");
                String age = req.getParameter("age");
                String major = req.getParameter("major");
                Student student = new Student();
                student.setId(Integer.parseInt(id));
                student.setName(name);
                student.setAge(Integer.parseInt(age));
                student.setMajor(major);
                studentService.editStudent(student);
                req.getRequestDispatcher("/findStudent").forward(req, resp);
            } else if (path.contains("remove")) {
                String id = req.getParameter("id");
                studentService.removeStudent(Integer.parseInt(id));
                req.getRequestDispatcher("/findStudent").forward(req, resp);
            } else if (path.contains("get")) {
                String id = req.getParameter("id");
                Student student = studentService.findStudentById(Integer.parseInt(id));
                req.setAttribute("student", student);
                req.getRequestDispatcher("/student_edit.jsp").forward(req, resp);
            }
        }
    }

#### 7.4.5 页面 ####

**index.jsp：**

**student.jsp：**

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
    <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
    <html>
    <head>
        <base href="${pageContext.request.contextPath}/">
        <title>Title</title>
    </head>
    <body>
        <div style="text-align: center;">
            <h1>学生列表</h1>
             <a href="student_add.jsp">新增</a>
            <table border="1" width="600" align="center">
                <tr>
                    <th>编号</th>
                    <th>姓名</th>
                    <th>年龄</th>
                    <th>专业</th>
                    <th>操作</th>
                </tr>
                <c:forEach items="${list}" var="s">
                    <tr>
                        <td>${s.id}</td>
                        <td>${s.name}</td>
                        <td>${s.age}</td>
                        <td>${s.major}</td>
                        <td>
                            <a href="getStudent?id=${s.id}">编辑</a>  
                            <a href="removeStudent?id=${s.id}" onclick="return confirm('确定要删除吗?')">删除</a>
                        </td>
                    </tr>
                </c:forEach>
            </table>
        </div>
    </body>
    </html>

**student\_add.jsp：**

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
    <html>
    <head>
        <base href="${pageContext.request.contextPath}/">
        <title>Title</title>
    </head>
    <body>
        <div style="text-align: center">
            <h1>学生新增</h1>
            <form action="addStudent" method="post">
                <p>
                    <label>姓名</label>
                    <input type="text" name="name"/>
                </p>
                <p>
                    <label>年龄</label>
                    <input type="text" name="age"/>
                </p>
                <p>
                    <label>专业</label>
                    <input type="text" name="major"/>
                </p>
                <p>
                    <button type="submit">提交</button>
                </p>
            </form>
        </div>
    </body>
    </html>

**student\_edit.jsp：**

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
    <html>
    <head>
        <base href="${pageContext.request.contextPath}/">
        <title>Title</title>
    </head>
    <body>
        <div style="text-align: center">
            <h1>学生编辑</h1>
            <form action="editStudent" method="post">
                <input type="hidden" name="id" value="${student.id}">
                <p>
                    <label>姓名</label>
                    <input type="text" name="name" value="${student.name}"/>
                </p>
                <p>
                    <label>年龄</label>
                    <input type="text" name="age" value="${student.age}"/>
                </p>
                <p>
                    <label>专业</label>
                    <input type="text" name="major" value="${student.major}"/>
                </p>
                <p>
                    <button type="submit">提交</button>
                </p>
            </form>
        </div>
    </body>
    </html>