ssm框架详细讲解（一）

淩亂°似流年 2022-01-07 11:31 641阅读 0赞

## ![20190627103007402.png][] ##

# SSM运行流程讲解 #

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTc2NzYx_size_16_color_FFFFFF_t_70][]

## **各层之间的联系:** ##

![20190627104131187.png][]

### 运行流程 ###

![20190627104233115.png][]

## **SSM框架实现一个web程序主要使用到如下三个技术** ##

![20190627104324315.png][]

## **比如你开发项目的时候，需要完成一个功能模块：** ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTc2NzYx_size_16_color_FFFFFF_t_70 1][]

## 个个框架详细讲解 ##

## Mybatis: ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTc2NzYx_size_16_color_FFFFFF_t_70 2][]

### 入门案列： ###

> 1.在pom.xml中添加依赖

<dependencies>
            
            <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>4.12</version>
                <scope>test</scope>
            </dependency>
            
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>5.1.46</version>
            </dependency>
            
            <dependency>
                <groupId>org.mybatis</groupId>
                <artifactId>mybatis</artifactId>
                <version>3.4.6</version>
            </dependency>
            
            <dependency>
                <groupId>log4j</groupId>
                <artifactId>log4j</artifactId>
                <version>1.2.17</version>
            </dependency>
        </dependencies>

> 2.创建JavaBean

package com.itheima.domain;
    
    import lombok.Data;
    import lombok.ToString;
    
    import java.util.Date;
    
    /***
     * JavaBean
     */
    @Data
    @ToString
    public class User {
        private Integer id;
        private String username;
        private Date birthday;
        private String sex;
        private String address;
    }

### 编写Mybatis的代码，查询所有用户 ###

### 1.1创建dao接口（映射器） ###

![20190627111430588.png][]

### 1.2准备映射器的配置文件xml ###

![20190627111640675.png][]

<?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.itheima.dao.UserDao">
        
        <select id="queryAll" resultType="com.itheima.domain.User">
            select * from user
        </select>
    </mapper>

> **参数讲解：resultType,结果集的封装类型**
> 
> **                  id:给接口那个方法配置的**

### 1.3准备Mybatis的日志配置文件 ###

# Set root category priority to INFO and its only appender to CONSOLE.
    #log4j.rootCategory=INFO, CONSOLE            debug   info   warn error fatal
    log4j.rootCategory=debug, CONSOLE, LOGFILE
    
    # Set the enterprise logger category to FATAL and its only appender to CONSOLE.
    log4j.logger.org.apache.axis.enterprise=FATAL, CONSOLE
    
    # CONSOLE is set to be a ConsoleAppender using a PatternLayout.
    log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender
    log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout
    log4j.appender.CONSOLE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n
    
    # LOGFILE is set to be a File appender using a PatternLayout.
    log4j.appender.LOGFILE=org.apache.log4j.FileAppender
    log4j.appender.LOGFILE.File=d:\axis.log
    log4j.appender.LOGFILE.Append=true
    log4j.appender.LOGFILE.layout=org.apache.log4j.PatternLayout
    log4j.appender.LOGFILE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n

## 1.5准备Mybatis的核心配置文件xml ##

![20190627112306503.png][]

<?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE configuration
            PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
            "http://mybatis.org/dtd/mybatis-3-config.dtd">
    
    <configuration>
        
        <environments default="mysql_mybatis">
            
            <environment id="mysql_mybatis">
                
                <transactionManager type="JDBC"/>
                
                <dataSource type="POOLED">
                    <property name="driver" value="com.mysql.jdbc.Driver"/>
                    <property name="url" value="jdbc:mysql:///mybatis63"/>
                    <property name="username" value="root"/>
                    <property name="password" value="root"/>
                </dataSource>
            </environment>
        </environments>
    
        
        <mappers>
            <mapper resource="com/itheima/dao/UserDao.xml"/>
        </mappers>
    </configuration>

## ![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTc2NzYx_size_16_color_FFFFFF_t_70 3][] ##

## 1.6编写测试代码 ##

package com.itheima;
    
    import com.itheima.dao.UserDao;
    import com.itheima.domain.User;
    import org.apache.ibatis.io.Resources;
    import org.apache.ibatis.session.SqlSession;
    import org.apache.ibatis.session.SqlSessionFactory;
    import org.apache.ibatis.session.SqlSessionFactoryBuilder;
    import org.junit.Test;
    
    import java.io.IOException;
    import java.io.InputStream;
    import java.util.List;
    
    public class TestDemo01 {
        @Test
        public void testQuickStart() throws IOException {
            //1. 读取核心配置文件SqlMapConfig.xml
            InputStream is = Resources.getResourceAsStream("SqlMapConfig.xml");
            //2. 创建SqlSessionFactoryBuilder构造者对象
            SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
            //3. 使用构造者builder，根据配置文件的信息is，构造一个SqlSessionFactory工厂对象
            SqlSessionFactory factory = builder.build(is);
            //4. 使用工厂对象factory，生产一个SqlSession对象
            SqlSession session = factory.openSession();
            //5. 使用SqlSession对象，获取映射器UserDao接口的代理对象
            UserDao dao = session.getMapper(UserDao.class);
            //6. 调用UserDao代理对象的方法，查询所有用户
            List<User> users = dao.queryAll();
            for (User user : users) {
                System.out.println(user);
            }
            //7. 释放资源
            session.close();
            is.close();
        }
    }

## 常用的配置中的内容讲解 ##

> **resultType：是查询select标签上才有的，用来设置查询的结果集要封装成什么类型的** 
> 
> **POJO（JavaBean）**：JavaBean的属性名要和字段名保持一致

### JavaBean中属性名和字段名不一致的情况处理 ###

> 实现方案一：SQL语句中使用别名，别名和JavaBean属性名保持一致（用的少）
> 
> ![20190627142456567.png][]
> 
> 实现方案二：使用resultMap配置字段名和属性名的对应关系（推荐）
> 
> （1）在映射器中UserDao中增加方法
> 
> ![20190627142638418.png][]
> 
> (2)在映射配置文件中UserDao.xml中增加statement
> 
> ![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTc2NzYx_size_16_color_FFFFFF_t_70 4][]
> 
> (3）在单元中测试类中编写测试代码
> 
> ![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTc2NzYx_size_16_color_FFFFFF_t_70 5][]

## ==SQL深入-动态sql== ##

## 常用的注解（重点） ##

## Spring: ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTc2NzYx_size_16_color_FFFFFF_t_70 6][]

## SpringMVC: ##

![20190627104648539.png][]

### 运行流程 ###

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTc2NzYx_size_16_color_FFFFFF_t_70 7][]

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