云笔记
JSON 是什么
JSON 就是JS的一部分: JSON 是 JavaScript中的对象直接量语法, 用于声明JS对象.
如:
var i = 5;
var str = 'abc';
var obj = {age:5, name:'Tom'};
var ary = ['Tom','Jerry','Andy'];
var list = [{name:"Tom",age:8},{name:"Jerry",age:9}];
符合JSON语法的字符串称为JSON字符串:
var str = '{"name":"Tom","age":6}';
var str = '["name","Tom","age"]';
如何将JSON字符串转换为JSON对象(JS对象)
var obj = eval("("+str+")");
Spring MVC 支持AJAX原理
需求分析
软件= 数据结构+算法
设计数据的存储
内存: 数据临时计算存储场所, 关闭电源就消失, 称为瞬态的
- 运行内存
- 分配的是对象
外存: (SSD固体硬盘, HDD机械硬盘, SD, 闪存, U盘), 关闭电源不消失, 称为持久状态
- 存储容量
- 保存的是文件 单机(单线程)程序可以使用文件存储数据
- 数据库(文件) 数据库管理系统,提供了并发访问管理! 适合多线程访问
云笔记采用数据库存储数据!
设计数据的存储
ER 图:
MySQL的简单使用
使用MySQL命令行工具
- Windows 用户使用: MySQL Client, 输入密码
Linux:
mysql -u用户名 -p密码 mysql -uroot -p
显示数据库命令
show databases;创建数据库命令
create database 数据库名;删除数据库命令
drop database 数据库名;切换当前数据库
use 数据库名 use mysql显示当前数据库中的全部表
show tables;建表语句, 在当前数据库中创建表
create table 表名 (列的声明...)设置当前命令行窗口的编码: 设置当前窗口的文本编码为UTF-8
set names utf8;执行sql脚本命令: 执行文本文件中的一批SQL命令.
如果SQL文件是UTF-8编码的, 就必须先执行 set names utf8;
source 文本文件的路径名;
source D:\Robin\Note\note_ziliao\cloud_note.sql
source /home/soft01/note_ziliao/cloud_note.sql
请注意: 一定要清楚路径, 保障路径的正确性!!!
案例: 执行脚本建立数据表:
source /home/soft01/note_ziliao/cloud_note.sql
show databases;
use cloud_note;
show tables;
案例: 创建一张表, 并且插入数据.
create database demo;
use demo
create table MyTable(id int, name varchar(100));
insert into MyTable (id, name) values (1, 'Tom');
insert into MyTable (id, name) values (2, 'Jerry');
select id, name from MyTable;
drop table MyTable;
drop database demo;
环境搭建
- 创建项目
- 创建Maven项目
- 生成web.xml
- 导入目标运行环境:Tomcat运行环境
导入要的包: pom.xml
<dependency><groupId>org.springframework</groupId><artifactId>spring-webmvc</artifactId><version>3.2.8.RELEASE</version> </dependency> <dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-annotations</artifactId><version>2.2.3</version> </dependency> <dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-core</artifactId><version>2.2.3</version> </dependency> <dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-databind</artifactId><version>2.2.3</version> </dependency><dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>3.2.8</version> </dependency> <dependency><groupId>org.mybatis</groupId><artifactId>mybatis-spring</artifactId><version>1.2.3</version> </dependency> <dependency><groupId>org.springframework</groupId><artifactId>spring-jdbc</artifactId><version>3.2.8.RELEASE</version> </dependency> <dependency><groupId>commons-dbcp</groupId><artifactId>commons-dbcp</artifactId><version>1.4</version> </dependency><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.12</version> </dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.6</version> </dependency>配置Spring MVC控制器: web.xml
<servlet><description></description><display-name>DispatcherServlet</display-name><servlet-name>DispatcherServlet</servlet-name><servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class><init-param><description></description><param-name>contextConfigLocation</param-name><param-value>classpath:conf/spring-*.xml</param-value></init-param><load-on-startup>1</load-on-startup></servlet><servlet-mapping><servlet-name>DispatcherServlet</servlet-name><url-pattern>*.do</url-pattern></servlet-mapping>添加Spring-MVC 配置文件: conf/spring-mvc.xml
<!-- 配置组件扫描 --> <context:component-scan base-package="cn.tedu.note.controller"/> <!-- 配置MVC注解扫描 --> <mvc:annotation-driven />添加数据库连接参数文件: conf/jdbc.properties:
driver=com.mysql.jdbc.Driver url=jdbc:mysql://localhost:3306/cloud_note user=root password=root maxActive=20配置MyBatis: conf/spring-mybatis.xml
<!-- 配置 spring-mybatis.xml --> <!-- 读取配置文件 --> <util:properties id="jdbc"location="classpath:conf/jdbc.properties"/> <!-- 配置数据库连接池 --> <bean id="dataSource"class="org.apache.commons.dbcp.BasicDataSource"destroy-method="close"> <property name="driverClassName"value="#{jdbc.driver}"/><property name="url"value="#{jdbc.url}"/><property name="username"value="#{jdbc.user}"/><property name="password"value="#{jdbc.password}"/><property name="maxActive"value="#{jdbc.maxActive}"></property> </bean><!-- 配置MyBatis的 SessionFactory --> <bean id="sqlSessionFactory"class="org.mybatis.spring.SqlSessionFactoryBean"><property name="dataSource"ref="dataSource"/><property name="mapperLocations"value="classpath:mapper/*.xml"/></bean> <!-- Mapper接口组件扫描 --> <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer"><property name="basePackage" value="cn.tedu.note.dao"/> </bean>
登录功能
程序 = 数据结构 + 算法
编程思路:
- 搞清楚业务需求.
- 考虑数据如何存储.
- 如何操作数据才能达到业务目的
- 设计SQL
- 编程: 将业务功能和数据操作整合起来, 如何编程才能执行SQL操作数据
1. 数据持久层开发
添加UserDao接口:
public interface UserDao {User findUserByName(String name);}添加实体类 User
public class User implements Serializable{private static final long serialVersionUID = -288301177049569372L;private String id;private String name;private String password;private String token;private String nick;public User() {}public User(String id, String name, String password, String token, String nick) {super();this.id = id;this.name = name;this.password = password;this.token = token;this.nick = nick;}public String getId() {return id;}public void setId(String id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}public String getToken() {return token;}public void setToken(String token) {this.token = token;}public String getNick() {return nick;}public void setNick(String nick) {this.nick = nick;}@Overridepublic String toString() {return "User [id=" + id + ", name=" + name + ", password=" + password + ", token=" + token + ", nick=" + nick+ "]";}@Overridepublic int hashCode() {final int prime = 31;int result = 1;result = prime * result + ((id == null) ? 0 : id.hashCode());return result;}@Overridepublic boolean equals(Object obj) {if (this == obj)return true;if (obj == null)return false;if (getClass() != obj.getClass())return false;User other = (User) obj;if (id == null) {if (other.id != null)return false;} else if (!id.equals(other.id))return false;return true;} }添加SQL: mapper/UserMapper.xml:
<mapper namespace="cn.tedu.note.dao.UserDao"><select id="findUserByName" parameterType="string"resultType="cn.tedu.note.entity.User">select cn_user_id as id,cn_user_name as name,cn_user_password as password,cn_user_token as token,cn_user_nick as nickfromcn_user wherecn_user_name = #{name}</select></mapper>测试 UserDaoTest:
public class UserDaoTest {ClassPathXmlApplicationContext ctx;@Before public void initCtx(){ctx = new ClassPathXmlApplicationContext("conf/spring-mvc.xml","conf/spring-mybatis.xml");}@Afterpublic void closeCtx(){ctx.close();}@Testpublic void testFindUserByName(){String name = "demo";UserDao dao = ctx.getBean("userDao", UserDao.class);User user = dao.findUserByName(name);System.out.println(user); } }Good Luck!