08.MyBatis源码分析笔记–编写测试代码
MyBatis 配置
mybatis-config.xml
位置：mybatis-3\src\main\resources\mybatis-config.xml
<?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>
<properties resource="config.properties">
</properties>
<typeAliases>
<typeAlias type="org.apache.ibatis.demo.pojo.User" alias="user"></typeAlias>
</typeAliases>
<plugins>
<!--监控 sql 埋点 分页-->
<plugin interceptor="org.apache.ibatis.demo.plugin.SqlPrintInterceptor"></plugin>
</plugins>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="${driver}"/>
<property name="url" value="${url}"/>
<property name="username" value="${username}"/>
<property name="password" value="${password}"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="mapper/UserMapper.xml"/>
</mappers>
</configuration>
config.properties
位置：mybatis-3\src\main\resources\config.properties
driver=com.mysql.cj.jdbc.Driver
#url=jdbc:mysql://127.0.0.1:3306/mybatis_learn?characterEncoding=utf8&serverTimezone=UTC&useSSL=false
url=jdbc:mysql://127.0.0.1:3306/mybatis_learn?characterEncoding=utf8&serverTimezone=UTC&useSSL=false
#url=jdbc:mysql://127.0.0.1:3306/mybatis_learn
username=root
password=root123456
MyBatis Plugin
SqlPrintInterceptor.java
位置：mybatis-3\src\test\java\org\apache\ibatis\demo\plugin\SqlPrintInterceptor.java
package org.apache.ibatis.demo.plugin;
import org.apache.ibatis.executor.Executor;
import org.apache.ibatis.mapping.BoundSql;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.ParameterMapping;
import org.apache.ibatis.mapping.ParameterMode;
import org.apache.ibatis.plugin.*;
import org.apache.ibatis.reflection.MetaObject;
import org.apache.ibatis.session.Configuration;
import org.apache.ibatis.session.ResultHandler;
import org.apache.ibatis.session.RowBounds;
import org.apache.ibatis.type.TypeHandlerRegistry;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
import java.util.Properties;
import java.util.regex.Matcher;
@Intercepts
({
@Signature(type = Executor.class, method = "query", args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class}),
@Signature(type = Executor.class, method = "update", args = {MappedStatement.class, Object.class})
})
public class SqlPrintInterceptor implements Interceptor {
private static final Logger log = LoggerFactory.getLogger(SqlPrintInterceptor.class);
private static final DateFormat DATE_FORMAT = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
@Override
public Object intercept(Invocation invocation) throws Throwable {
MappedStatement mappedStatement = (MappedStatement) invocation.getArgs()[0];
Object parameterObject = null;
if (invocation.getArgs().length > 1) {
parameterObject = invocation.getArgs()[1];
}
long start = System.currentTimeMillis();
Object result = invocation.proceed();
String statementId = mappedStatement.getId();
BoundSql boundSql = mappedStatement.getBoundSql(parameterObject);
Configuration configuration = mappedStatement.getConfiguration();
String sql = getSql(boundSql, parameterObject, configuration);
long end = System.currentTimeMillis();
long timing = end - start;
if(log.isInfoEnabled()){
log.info("执行sql耗时:" + timing + " ms" + " - id:" + statementId + " - Sql:" );
log.info(" "+sql);
}
return result;
}
@Override
public Object plugin(Object target) {
if (target instanceof Executor) {
return Plugin.wrap(target, this);
}
return target;
}
@Override
public void setProperties(Properties properties) {
}
private String getSql(BoundSql boundSql, Object parameterObject, Configuration configuration) {
String sql = boundSql.getSql().replaceAll("[\\s]+", " ");
List<ParameterMapping> parameterMappings = boundSql.getParameterMappings();
TypeHandlerRegistry typeHandlerRegistry = configuration.getTypeHandlerRegistry();
if (parameterMappings != null) {
for (int i = 0; i < parameterMappings.size(); i++) {
ParameterMapping parameterMapping = parameterMappings.get(i);
if (parameterMapping.getMode() != ParameterMode.OUT) {
Object value;
String propertyName = parameterMapping.getProperty();
if (boundSql.hasAdditionalParameter(propertyName)) {
value = boundSql.getAdditionalParameter(propertyName);
} else if (parameterObject == null) {
value = null;
} else if (typeHandlerRegistry.hasTypeHandler(parameterObject.getClass())) {
value = parameterObject;
} else {
MetaObject metaObject = configuration.newMetaObject(parameterObject);
value = metaObject.getValue(propertyName);
}
sql = replacePlaceholder(sql, value);
}
}
}
return sql;
}
private String replacePlaceholder(String sql, Object propertyValue) {
String result;
if (propertyValue != null) {
if (propertyValue instanceof String) {
result = "'" + propertyValue + "'";
} else if (propertyValue instanceof Date) {
result = "'" + DATE_FORMAT.format(propertyValue) + "'";
} else {
result = propertyValue.toString();
}
} else {
result = "null";
}
return sql.replaceFirst("\\?", Matcher.quoteReplacement(result));
}
}
业务类
建表 SQL
CREATE TABLE `mybatis_user` (
`id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT '主键ID',
`username` varchar(255) DEFAULT NULL COMMENT '姓名',
`age` int(11) DEFAULT NULL COMMENT '年龄',
`phone` bigint(20) DEFAULT NULL COMMENT '电话号码',
`description` varchar(255) DEFAULT NULL COMMENT '描述',
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=15 DEFAULT CHARSET=utf8mb4;
entities
User.java
位置：mybatis-3\src\test\java\org\apache\ibatis\demo\pojo\User.java
package org.apache.ibatis.demo.pojo;
import java.io.Serializable;
public class User implements Serializable {
private Long id;
private String username;
private Integer age;
private Long phone;
private String description;
//Getter和Setter方法略
//toString方法略
}
DAO 层
UserMapper.java
位置：mybatis-3\src\test\java\org\apache\ibatis\demo\mapper\UserMapper.java
package org.apache.ibatis.demo.mapper;
import org.apache.ibatis.demo.pojo.User;
public interface UserMapper {
User selectUser(Integer id);
}
UserMapper.xml
位置：mybatis-3\src\main\resources\mapper\UserMapper.xml
<?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="org.apache.ibatis.demo.mapper.UserMapper">
<resultMap id="BaseResultMap" type="user">
<id column="id" jdbcType="BIGINT" property="id" />
<result column="username" jdbcType="VARCHAR" property="username" />
<result column="age" jdbcType="INTEGER" property="age" />
<result column="phone" jdbcType="BIGINT" property="phone" />
<result column="description" jdbcType="VARCHAR" property="description" />
</resultMap>
<select id="selectUser" parameterType="integer" resultType="user" resultMap="BaseResultMap">
select * from mybatis_user where id = #{id}
</select>
</mapper>
测试类
MybatisMain.java
位置：mybatis-3\src\test\java\org\apache\ibatis\demo\MybatisMain.java
package org.apache.ibatis.demo;
import org.apache.ibatis.demo.pojo.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 java.io.IOException;
import java.io.InputStream;
public class MybatisMain {
public static void main(String[] args) throws IOException {
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
SqlSession sqlSession = sqlSessionFactory.openSession();
//mapper namespace 和 select id
User user = sqlSession.selectOne("org.apache.ibatis.demo.mapper.UserMapper.selectUser", 11);
System.out.println(user);
}
}
