9.参数的传递

转载 于 2017-12-24 20:38:00 发布 · 98 阅读 · 0 ·
CC 4.0 BY-SA版权
原文链接：http://www.cnblogs.com/tournesol/p/8099146.html
文章标签：

#java #数据库

1.参数的传递
      1)形参的索引，#{0}从0开始
      2)形参的索引，#{param1}从1开始
      3)对象，通过对象的属性访问
      4)Map，通过key来访问
      5)注解(@Param("name"))
      6)用那个
             1)如果方法的参数大于3个要么封装成对象，要么封装成Map
             2)如果方法的形参小于3个参数就用注解

创建数据库：

 

1.创建项目

 

2.建包建配置文件

   com.qf.entity

   com.qf.dao

   com.qf.mapper

   com.qf.utils

mybatis-config.xml  

3.con.qf.entity包中创建实体类

 

package com.qf.entity;

import org.apache.ibatis.type.Alias;

public class User {

	private Integer id;
	
	private String name;
	
	private String password;
	private String isAdmin;

	public String getPassword() {
		return password;
	}

	public void setPassword(String password) {
		this.password = password;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public Integer getId() {
		return id;
	}

	public void setId(Integer id) {
		this.id = id;
	}

	public String getIsAdmin() {
		return isAdmin;
	}

	public void setIsAdmin(String isAdmin) {
		this.isAdmin = isAdmin;
	}

	@Override
	public String toString() {
		return "User [id=" + id + ", name=" + name + ", password=" + password + ", isAdmin=" + isAdmin + "]";
	}

	
}

　　

4.con.qf.dao包中创建接口

 

package com.qf.dao;

import java.util.Map;

import org.apache.ibatis.annotations.Param;

import com.qf.entity.User;

public interface IUserDao {

	public User getUserById(Integer id);

	public void add(User user);

	public User login(String name,String password);
	
	public User login2(User user);
	
	public User login3(Map<String,Object> map);
	
	public User login4(@Param("name")String name,@Param("password")String password);
}

 

5.配置jdbc.properties配置文件

jdbc.url =jdbc:mysql://localhost:3306/1708_mybatis
jdbc.name=root
jdbc.password=root
jdbc.driver=com.mysql.jdbc.Driver　

配置mybatis-config.xml配置文件

<?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>

	<!-- 加载属性文件 
		resource:本地资源文件
	-->
	<properties resource="jdbc.properties"></properties>

	<typeAliases>
		<!-- 给一个对象起别名 -->
   <!-- <typeAlias type="com.qf.entity.User" alias="user"/> -->

		<!-- 给一个包下面的所有类起别名，默认的别名是类名首字母小写,可以通过@Alias注解修改默认的别名 -->
			<package name="com.qf.entity"/>
	</typeAliases>

	<environments default="development">
		<environment id="development">
			<transactionManager type="JDBC" />
			<dataSource type="POOLED">
				<property name="driver" value="${jdbc.driver}" />
				<property name="url" value="${jdbc.url}" />
				<property name="username" value="${jdbc.name}" />
				<property name="password" value="${jdbc.password}" />
			</dataSource>
		</environment>
	</environments>
	
</configuration>

　　

6.com.qf.mapper包创建接口的映射文件

<?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">

<!-- namespace指的就是接口的全类名 -->
<mapper namespace="com.qf.dao.IUserDao">
	<resultMap type="com.qf.entity.User" id="userMap2">
		<result column="is_admin" property="isAdmin" />
	</resultMap>
	<resultMap type="com.qf.entity.User" id="userMap" extends="userMap2">
		<id column="id" property="id" />
		<result column="name" property="name" />
		<result column="password" property="password" />
	</resultMap>

	<!-- id:方法名称 resultType:返回类型 -->
	<select id="getUserById" resultMap="userMap">
		select * from t_user where
		id
		= #{id}
	</select>

	<!-- parameterType:方法的参数类型 -->
	<insert id="add" parameterType="user">
		insert into t_user
		(name,password) values(#{name},#{password})
	</insert>

	<!--第一种方式通过方法形参的索引，从0开始 -->
	<!-- <select id="login" resultMap="userMap"> select * from t_user where 
		name=#{0} and password=#{1} </select> -->
	
	<!--第二种方式通过方法形参的索引，从param1开始 -->
	<select id="login" resultMap="userMap">
		select * from t_user where
		name=#{param1} and password=#{param2}

	</select>
	
	<!-- 第三种方式通过方法是个对象，通过属性名从取值 -->
	<select id="login2" resultMap="userMap" parameterType="User">
		select *
		from t_user where name=#{name} and password=#{password}
	</select>
	
	<!-- 第四种方式通过方法是个Map，通过key来取值 -->
	<select id="login3" resultMap="userMap" parameterType="User">
		select *
		from t_user where name=#{name} and password=#{password}
	</select>
	
	<!-- 第五种方式方法传递多个参数，用注解中的中的内容来取值 -->
	<select id="login4" resultMap="userMap" parameterType="User">
		select *
		from t_user where name=#{name} and password=#{password}
	</select>
</mapper>

　　

7.在mybatis-config.xml里面读取Mapper文件

 

	<!-- Mapper文件 -->
	<mappers>
		<mapper resource="com/qf/mapper/IUserDao.xml" />
	</mappers>

 

　　

 

8.com.qf.util工具类

package com.qf.utils;

import java.io.IOException;
import java.io.InputStream;

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.xml.sax.InputSource;

public class MyBatisUtil {

	private static SqlSessionFactory sqlSessionFactory;

	public static SqlSessionFactory getSqlSessionFactory() {

		if (sqlSessionFactory == null) {
			initSqlSessionFactory(); // 为空再去参加
		}
		return sqlSessionFactory;
	}

	private static void initSqlSessionFactory() {
		InputStream ips = null;
		try {
			// 1.指定配置文件
			ips = Resources.getResourceAsStream("mybatis-config.xml");

			// 2.赋值操作
			synchronized (MyBatisUtil.class) {
				if (sqlSessionFactory == null) {
					sqlSessionFactory = new SqlSessionFactoryBuilder().build(ips);
				}
			}

		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			if (ips != null) {
				try {
					ips.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}
	}
}

　　

9.测试类

package com.qf.dao;

import java.util.HashMap;
import java.util.Map;

import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.log4j.Logger;
import org.junit.Test;

import com.qf.entity.User;
import com.qf.utils.MyBatisUtil;

public class UserDaoTest {

	private Logger logger = Logger.getLogger(UserDaoTest.class);

	@Test
	public void testGetUserById() {
		SqlSession sqlSession = MyBatisUtil.getSqlSessionFactory().openSession();

		IUserDao userDao = sqlSession.getMapper(IUserDao.class);

		User user = userDao.getUserById(7);
		System.out.println(user);
		sqlSession.close();
	}

	/**
	 * 测试：1第一种方式通过方法形参的索引，从0开始
	 */
	@Test
	public void testLogin() {
		SqlSessionFactory sqlSessionFactory = MyBatisUtil.getSqlSessionFactory();
		SqlSession sqlSession = sqlSessionFactory.openSession();
		IUserDao userDao = sqlSession.getMapper(IUserDao.class);
		User user = userDao.login("张三", "123");
		System.out.println(user);
		sqlSession.commit();
		sqlSession.close();

	}
	/**
	 * 第二种方式通过方法形参的索引，从param1开始
	 */
	@Test
	public void testLogin1() {
		SqlSessionFactory sqlSessionFactory = MyBatisUtil.getSqlSessionFactory();
		SqlSession sqlSession = sqlSessionFactory.openSession();
		IUserDao userDao = sqlSession.getMapper(IUserDao.class);
		User user = userDao.login("张三", "123");
		System.out.println(user);
		sqlSession.commit();
		sqlSession.close();

	}
	/**
	 * 第三种方式通过方法是个对象，通过属性名从取值
	 */
	@Test
	public void testLogin2() {
		SqlSessionFactory sqlSessionFactory = MyBatisUtil.getSqlSessionFactory();
		SqlSession sqlSession = sqlSessionFactory.openSession();
		IUserDao userDao = sqlSession.getMapper(IUserDao.class);
		
		User user =new User();
		user.setName("张三");
		user.setPassword("123");
		
		user = userDao.login2(user);
		System.out.println(user);
		sqlSession.commit();
		sqlSession.close();

	}
	/**
	 * 第四种方式通过方法是个Map，通过key来取值
	 */
	@Test
	public void testLogin3() {
		SqlSessionFactory sqlSessionFactory = MyBatisUtil.getSqlSessionFactory();
		SqlSession sqlSession = sqlSessionFactory.openSession();
		IUserDao userDao = sqlSession.getMapper(IUserDao.class);
		
		Map<String,Object> map=new HashMap<String,Object>();
		map.put("name", "张三");
		map.put("password", "123");
	
	  
	 	 User user = userDao.login3(map);
	 	 
		System.out.println(user);
		sqlSession.commit();
		sqlSession.close();

	}
	/**
	 * 第五种方式方法传递多个参数，用注解中的中的内容来取值
	 */
	@Test
	public void testLogin4() {
		SqlSessionFactory sqlSessionFactory = MyBatisUtil.getSqlSessionFactory();
		SqlSession sqlSession = sqlSessionFactory.openSession();
		IUserDao userDao = sqlSession.getMapper(IUserDao.class);
		
		User user = userDao.login4("张三", "123");
		System.out.println(user);
		sqlSession.commit();
		sqlSession.close();

	}
}

　　

 

转载于:https://www.cnblogs.com/tournesol/p/8099146.html

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