ssm-數據庫的基本操作

1.創建項目，現在我們需要了解到我們索要操作的數據庫中表中的有哪些鍵值。

比如這張表中有id，name，age(此表內有數據)
那麼我們需要先創建一個Modul層（UserModel.java）

public class UserModel {
    private int id;
    private String name;
    private int age;

    //getter and setter
    public UserModel(int id, String name, int age) {
        this.id = id;
        this.name = name;
        this.age = age;
    }
    @Override
    public String toString() {
        return "UserModel{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
}

表涉及到增刪改查，所以就創建出一個Dao層（UserDao.java）

package com.cm.dao;

import com.cm.model.UserModel;
import java.util.List;

public interface UserDao {
    List<UserModel> getAllUsers();//查詢全部數據
    UserModel getUser(String id);//查詢某個id的信息
    boolean addUser(UserModel userModel);
    boolean updateUser(String id, String name);
    boolean deleteUser(String id);
}

接下來實現Dao層

package com.cm.dao;

import com.cm.model.UserModel;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowCallbackHandler;
import org.springframework.stereotype.Repository;

import javax.annotation.Resource;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

@Repository("userDaoImpl")
public class UserDaoImpl implements UserDao {
    @Resource(name = "myJdbc")
    private JdbcTemplate myJdbc;

    @Override
    public List<UserModel> getAllUsers() {
        String sql = "select * from user";
        return query(sql);
    }

    @Override
    public UserModel getUser(String id) {
        return null;
    }

    @Override
    public boolean addUser(UserModel userModel) {
        return false;
    }

    @Override
    public boolean updateUser(String id, String name) {
        return false;
    }

    @Override
    public boolean deleteUser(String id) {
        return false;
    }

    private List<UserModel> query(String sql) {
        final List<UserModel> userModels = new ArrayList<>();
        myJdbc.query(sql, new RowCallbackHandler() {
            @Override
            public void processRow(ResultSet resultSet) throws SQLException {
                int id = resultSet.getInt(1);
                String name = resultSet.getString(2);
                int age = resultSet.getInt(3);
                UserModel userModel = new UserModel(id, name, age);
                userModels.add(userModel);
            }
        });
        return userModels;
    }
}

再寫訪問路徑Controller層，也可以說是操作層

@Controller
@RequestMapping("user")
public class UserController {
    private UserDao userDao;

    @Autowired
    UserController (UserDao userDao){
        this.userDao = userDao;
    }

    @RequestMapping("getAllUsers")
    @ResponseBody
    public String getAllUsers() {
        List<UserModel> userModels = userDao.getAllUsers();
        return userModels.toString();
    }
}

上面的代碼塊涉及到Controller等註解，那麼需要配置註解掃描包，註解驅動器

<?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: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/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.xsd">

    <!-- 配置包掃描器 -->
    <context:component-scan base-package="com.cm.controller"/>
    <context:component-scan base-package="com.cm.model"/>
    <context:component-scan base-package="com.cm.dao"/>


    <!-- 配置註解驅動 -->
    <mvc:annotation-driven/>
    <!-- 視圖解析器 -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <!--前綴-->
        <property name="prefix" value="/WEB-INF/views/"/>
        <!--後綴-->
        <property name="suffix" value=".jsp"/>
    </bean>
</beans>

<!--web.xml-->
<!DOCTYPE web-app PUBLIC
        "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
        "http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>
  <display-name>Archetype Created Web Application</display-name>
  <!--Spring MVC 配置 並添加監聽-->
  <context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>classpath:applicationContext.xml</param-value>
  </context-param>

  <!-- 字符過濾器 傳值亂碼-->
  <filter>
    <filter-name>encodingFilter</filter-name>
    <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
    <init-param>
      <param-name>encoding</param-name>
      <param-value>UTF-8</param-value>
    </init-param>
  </filter>
  <filter-mapping>
    <filter-name>encodingFilter</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>

  <listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>

  <!--配置前端控制器 進行請求分發 DispatcherServlet本質也是一個Servlet -->
  <servlet>
    <!--名字可以自定義-->
    <servlet-name>SpringMVC</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>classpath:mvc-dispatcher.xml</param-value>
    </init-param>
    <!--標記容器啓動的時候就啓動這個servlet-->
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>SpringMVC</servlet-name>
    <!--攔截所有-->
    <url-pattern>/</url-pattern>
  </servlet-mapping>

</web-app>

項目運行：