MyBatis基础入门《十七》动态SQL
描述：
>> 完成多条件查询等逻辑实现
>> 用于实现动态SQL的元素主要有：
> if
> trim
> where
> set
> choose( when , otherwise )
> foreach
动态SQL为Mybatis重要部分，项目也重新新建了一个：mybatis-dynamic-sql
项目结构：
TblClient.java
1 package com.charles.entity;
2
3 import java.io.Serializable;
4 import java.util.Date;
5
6 public class TblClient implements Serializable {
7
8 private static final long serialVersionUID = -5993993584624176849L;
9
10 private Integer cid;
11 private String cname;
12 private String caddress;
13 private Date cbirthday;
14
15 public TblClient() {
16
17 }
18
19 public Integer getCid() {
20 return cid;
21 }
22
23 public void setCid(Integer cid) {
24 this.cid = cid;
25 }
26
27 public String getCname() {
28 return cname;
29 }
30
31 public void setCname(String cname) {
32 this.cname = cname;
33 }
34
35 public String getCaddress() {
36 return caddress;
37 }
38
39 public void setCaddress(String caddress) {
40 this.caddress = caddress;
41 }
42
43 public Date getCbirthday() {
44 return cbirthday;
45 }
46
47 public void setCbirthday(Date cbirthday) {
48 this.cbirthday = cbirthday;
49 }
50 }
ClientMapper.java
1 package com.charles.mapper;
2
3 import java.util.List;
4
5 import com.charles.entity.TblClient;
6
7 public interface ClientMapper {
8
9 /***
10 * 注意这个名字，必须要和ClientMapper.xml文件中的select标签id属性值一样。
11 * @return List<TblClient> 集合
12 */
13 public List<TblClient> getClientAll();
14
15 }
ClientMapper.xml
1 <?xml version="1.0" encoding="UTF-8" ?> 2 <!DOCTYPE mapper 3 PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" 4 "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> 5 6 <mapper namespace="com.charles.mapper.ClientMapper"> 7 8 <resultMap type="com.charles.entity.TblClient" id="tblClientID"> 9 <id property="cid" column="id" /> 10 <result property="cname" column="client_name"/> 11 <result property="caddress" column="client_address"/> 12 <result property="cbirthday" column="client_birthday"/> 13 </resultMap> 14 15 <select id="getClientAll" resultMap="tblClientID"> 16 SELECT 17 id , 18 client_name , 19 client_address , 20 client_birthday 21 FROM tbl_client 22 </select> 23 24 </mapper>
MyBatisUtil.java
1 package com.charles.util;
2
3 import java.io.IOException;
4 import java.io.InputStream;
5
6 import org.apache.ibatis.io.Resources;
7 import org.apache.ibatis.session.SqlSession;
8 import org.apache.ibatis.session.SqlSessionFactory;
9 import org.apache.ibatis.session.SqlSessionFactoryBuilder;
10
11 public class MyBatisUtil {
12
13 private static SqlSessionFactory factory = null;
14
15 /** 在静态代码块下，factory只会被创建一次 **/
16 static {
17 try {
18 InputStream inputStream = Resources.getResourceAsStream("mybatis/mybatis-config.xml");
19 factory = new SqlSessionFactoryBuilder().build(inputStream);
20 } catch (IOException e) {
21 e.printStackTrace();
22 }
23 }
24
25 // 获取factory
26 public static SqlSessionFactory getSessionFactory() {
27
28 return factory;
29 }
30
31 /**
32 * 获取SQLSession方法
33 *
34 * @return SQLSession
35 **/
36 public static SqlSession getSqlSession() {
37
38 // 开启事物
39 return factory.openSession(false);
40 }
41
42 /**
43 * 关闭SQLSession方法
44 *
45 * @param SQLSession对象
46 */
47 public static void closeSqlSession(SqlSession sqlSession) {
48
49 if (sqlSession != null) {
50 sqlSession.close();
51 }
52 }
53 }
mybatis-config.xml
1 <?xml version="1.0" encoding="UTF-8" ?>
2 <!DOCTYPE configuration
3 PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
4 "http://mybatis.org/dtd/mybatis-3-config.dtd">
5
6 <configuration>
7
8 <!--
9 注意：
10 这个配置文件的标签是有顺序的，必须按照这个顺序书写。
11 例如：settings标签就必须放在properties标签的后面。
12 -->
13
14 <!-- 引入database.properties文件 -->
15 <properties resource="properties/database.properties"></properties>
16
17 <!-- 配置mybatis的log实现log4j -->
18 <settings>
19 <setting name="logImpl" value="STDOUT_LOGGING" />
20 </settings>
21
22 <!-- 配置别名 -->
23 <typeAliases>
24 <typeAlias type="com.charles.entity.TblClient" alias="baitang" />
25 </typeAliases>
26
27 <!-- 配置Mybatis的环境 -->
28 <environments default="development">
29 <environment id="development">
30 <!-- 配置事物管理 -->
31 <transactionManager type="JDBC" />
32 <dataSource type="POOLED">
33 <property name="driver" value="${jdbc.driver}" />
34 <property name="url" value="${jdbc.url}" />
35 <property name="username" value="${jdbc.username}" />
36 <property name="password" value="${jdbc.password}" />
37 </dataSource>
38 </environment>
39 </environments>
40
41 <!-- 将Mapper文件加入到mybatis的配置文件中 -->
42 <mappers>
43 <mapper resource="com/charles/mapper/ClientMapper.xml" />
44 </mappers>
45
46
47 </configuration>
database.properties
jdbc.driver=com.mysql.jdbc.Driver
#jdbc.url=jdbc:mysql://IP地址:3306/test
jdbc.url=jdbc:mysql://IP地址:3306/test
jdbc.username=charles
jdbc.password=charles
lo4j.properties
# Global logging configuration
log4j.rootLogger=ERROR, stdout
# MyBatis logging configuration...
log4j.logger.com.charles=TRACE
# Console output...
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n
JunitSelect.java
1 package com.charles.junit;
2
3 import java.util.List;
4
5 import org.apache.ibatis.session.SqlSession;
6 import org.junit.Test;
7
8 import com.charles.entity.TblClient;
9 import com.charles.mapper.ClientMapper;
10 import com.charles.util.MyBatisUtil;
11
12 public class JunitSelect {
13
14 @Test
15 public void selectif() {
16
17 /** 1. 获取SQLSession **/
18 SqlSession session = MyBatisUtil.getSqlSession();
19
20 /** 2. 调度方法,从数据库中获取数据 **/
21 List<TblClient> list = session.getMapper(ClientMapper.class).getClientAll();
22
23 /** 3. 关闭SQLSession **/
24 MyBatisUtil.closeSqlSession(session);
25
26 for (TblClient client : list) {
27 System.out.println(client.getCid() + "\t" + client.getCname() + "\t" + client.getCaddress() + "\t"
28 + client.getCbirthday());
29 }
30 }
31 }
pom.xml
1 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 2 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> 3 <modelVersion>4.0.0</modelVersion> 4 <groupId>com.charles.mybatis</groupId> 5 <artifactId>mybatis-dynamic-sql</artifactId> 6 <version>0.0.1-SNAPSHOT</version> 7 8 <dependencies> 9 <dependency> 10 <groupId>junit</groupId> 11 <artifactId>junit</artifactId> 12 <version>4.11</version> 13 </dependency> 14 <dependency> 15 <groupId>log4j</groupId> 16 <artifactId>log4j</artifactId> 17 <version>1.2.17</version> 18 </dependency> 19 <dependency> 20 <groupId>org.mybatis</groupId> 21 <artifactId>mybatis</artifactId> 22 <version>3.4.6</version> 23 </dependency> 24 <dependency> 25 <groupId>mysql</groupId> 26 <artifactId>mysql-connector-java</artifactId> 27 <version>5.1.29</version> 28 </dependency> 29 </dependencies> 30 31 32 </project>
运行测试代码：JunitSelect.java 的测试结果：
如有问题，欢迎纠正！！！
如有转载，请标明源处：https://www.cnblogs.com/Charles-Yuan/p/9902779.html
原文地址：https://www.cnblogs.com/Charles-Yuan/p/9902779.html
时间： 2024-09-30 07:10:31