自定义持久层框架（仿MyBatis）

自定义框架设计

使用端：

提供核⼼配置⽂件：

sqlMapConfig.xml : 存放数据源信息，引⼊mapper.xml

Mapper.xml : sql语句的配置⽂件信息

框架端：

1.读取配置⽂件

读取完成以后以流的形式存在，我们不能将读取到的配置信息以流的形式存放在内存中，不好操作，可以创建javaBean来存储

（1）Configuration : 存放数据库基本信息、Map<唯⼀标识，Mapper>

唯⼀标识：namespace + "."+ id

（2）MappedStatement：sql语句、statement类型、输⼊参数java类型、输出参数java类型

2.解析配置⽂件

创建sqlSessionFactoryBuilder类：

⽅法：sqlSessionFactory build()：

第⼀：使⽤dom4j解析配置⽂件，将解析出来的内容封装到Configuration和MappedStatement中

第⼆：创建SqlSessionFactory的实现类DefaultSqlSession

3.创建SqlSessionFactory：

⽅法：openSession() : 获取sqlSession接⼝的实现类实例对象

4.创建sqlSession接⼝及实现类：主要封装crud⽅法

⽅法：selectList(String statementId,Object param)：查询所有

selectOne(String statementId,Object param)：查询单个

具体实现：封装JDBC完成对数据库表的查询操作

涉及到的设计模式：

Builder构建者设计模式、⼯⼚模式、代理模式

自定义框架实现

首先看一下整体结构

框架端：

使用端：

1.建库建表

/*
 Navicat Premium Data Transfer

 Source Server         : mysql
 Source Server Type    : MySQL
 Source Server Version : 80026
 Source Host           : 47.100.15.29:3306
 Source Schema         : zdy_mybatis

 Target Server Type    : MySQL
 Target Server Version : 80026
 File Encoding         : 65001

 Date: 29/11/2021 13:59:31
*/

SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;

-- ----------------------------
-- Table structure for user
-- ----------------------------
DROP TABLE IF EXISTS `user`;
CREATE TABLE `user`  (
  `id` int(0) NOT NULL,
  `username` varchar(50) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;

-- ----------------------------
-- Records of user
-- ----------------------------
INSERT INTO `user` VALUES (1, '小邹');
INSERT INTO `user` VALUES (2, '琪琪');

SET FOREIGN_KEY_CHECKS = 1;

在使⽤端（zdy-mybatis_test）项⽬中创建配置⽂件

2.创建 sqlMapConfig.xml

<configuration>
    <!--数据库配置信息-->
    <dataSource>
        <property name="driverClass" value="com.mysql.cj.jdbc.Driver"/>
        <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/zdy_mybatis"/>
        <property name="username" value="root"/>
        <property name="password" value="root"/>
    </dataSource>
    <!--存放mapper.xml的全路径-->
    <mapper resource="UserMapper.xml"/>
</configuration>

3.UserMapper.xml

<mapper namespace="com.zou.dao.IUserDao">
    <!--sql的唯一标识：namespace.id来组成 ： statementId-->
    <select id="findAll" resultType="com.zou.pojo.User" >
        select * from user
    </select>

    <select id="findByCondition" resultType="com.zou.pojo.User" paramterType="com.zou.pojo.User">
        select * from user where id = #{id} and username = #{username}
    </select>
</mapper>

4.User实体类

package com.zou.pojo;

/**
 * @author: 邹祥发
 * @date: 2021/11/29 08:43
 */
public class User {
    private Integer id;
    private String username;

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                '}';
    }

    public Integer getId() {
        return id;
    }

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

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }
}

5.再创建⼀个框架端（zdy-mybatis）并且导⼊需要⽤到的依赖坐标

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.zou</groupId>
    <artifactId>zdy-mybatis</artifactId>
    <version>1.0</version>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.encoding>UTF-8</maven.compiler.encoding>
        <java.version>1.8</java.version>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
    </properties>

    <dependencies>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.26</version>
        </dependency>
        <dependency>
            <groupId>c3p0</groupId>
            <artifactId>c3p0</artifactId>
            <version>0.9.1.2</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.12</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.10</version>
        </dependency>
        <dependency>
            <groupId>dom4j</groupId>
            <artifactId>dom4j</artifactId>
            <version>1.6.1</version>
        </dependency>
        <dependency>
            <groupId>jaxen</groupId>
            <artifactId>jaxen</artifactId>
            <version>1.1.6</version>
        </dependency>
    </dependencies>

</project>

6.Configuration

package com.zou.pojo;

import javax.sql.DataSource;
import java.util.HashMap;
import java.util.Map;

/**
 * @author: 邹祥发
 * @date: 2021/11/29 08:51
 */
public class Configuration {
    private DataSource dataSource;
    /**
     * key: statementid
     * value:封装好的mappedStatement对象
     */
    Map<String, MappedStatement> mappedStatementMap = new HashMap<>();

    public DataSource getDataSource() {
        return dataSource;
    }

    public void setDataSource(DataSource dataSource) {
        this.dataSource = dataSource;
    }

    public Map<String, MappedStatement> getMappedStatementMap() {
        return mappedStatementMap;
    }

    public void setMappedStatementMap(Map<String, MappedStatement> mappedStatementMap) {
        this.mappedStatementMap = mappedStatementMap;
    }
}

7.MappedStatement

package com.zou.pojo;

/**
 * @author: 邹祥发
 * @date: 2021/11/29 08:53
 */
public class MappedStatement {
    //id标识
    private String id;
    //返回值类型
    private String resultType;
    //参数值类型
    private String paramterType;
    //sql语句
    private String sql;

    public String getId() {
        return id;
    }

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

    public String getResultType() {
        return resultType;
    }

    public void setResultType(String resultType) {
        this.resultType = resultType;
    }

    public String getParamterType() {
        return paramterType;
    }

    public void setParamterType(String paramterType) {
        this.paramterType = paramterType;
    }

    public String getSql() {
        return sql;
    }

    public void setSql(String sql) {
        this.sql = sql;
    }
}

8.Resources

package com.zou.io;

import java.io.InputStream;

/**
 * @author: 邹祥发
 * @date: 2021/11/29 08:57
 */
public class Resources {
    // 根据配置文件的路径，将配置文件加载成字节输入流，存储在内存中
    public static InputStream getResourceAsSteam(String path) {
        return Resources.class.getClassLoader().getResourceAsStream(path);
    }
}

9.SqlSessionFactoryBuilder

package com.zou.sqlSession;

import com.zou.config.XMLConfigBuilder;
import com.zou.pojo.Configuration;
import org.dom4j.DocumentException;

import java.beans.PropertyVetoException;
import java.io.InputStream;

/**
 * @author: 邹祥发
 * @date: 2021/11/29 08:58
 */
public class SqlSessionFactoryBuilder {
    public SqlSessionFactory build(InputStream in) throws DocumentException, PropertyVetoException {
        // 第一：使用dom4j解析配置文件，将解析出来的内容封装到Configuration中
        XMLConfigBuilder xmlConfigBuilder = new XMLConfigBuilder();
        Configuration configuration = xmlConfigBuilder.parseConfig(in);
        // 第二：创建sqlSessionFactory对象：工厂类：生产sqlSession:会话对象
        DefaultSqlSessionFactory defaultSqlSessionFactory = new DefaultSqlSessionFactory(configuration);
        return defaultSqlSessionFactory;
    }
}

10.XMLConfigerBuilder

package com.zou.config;

import com.zou.io.Resources;
import com.zou.pojo.Configuration;
import com.mchange.v2.c3p0.ComboPooledDataSource;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

import java.beans.PropertyVetoException;
import java.io.InputStream;
import java.util.List;
import java.util.Properties;

/**
 * @author: 邹祥发
 * @date: 2021/11/29 09:01
 */
public class XMLConfigBuilder {

    private final Configuration configuration;

    public XMLConfigBuilder() {
        this.configuration = new Configuration();
    }

    /**
     * 该方法就是使用dom4j对配置文件进行解析，封装Configuration
     */
    public Configuration parseConfig(InputStream inputStream) throws DocumentException, PropertyVetoException {
        Document document = new SAXReader().read(inputStream);
        //<configuration>
        Element rootElement = document.getRootElement();
        List<Element> list = rootElement.selectNodes("//property");
        Properties properties = new Properties();
        for (Element element : list) {
            String name = element.attributeValue("name");
            String value = element.attributeValue("value");
            properties.setProperty(name, value);
        }
        //连接池
        ComboPooledDataSource comboPooledDataSource = new ComboPooledDataSource();
        comboPooledDataSource.setDriverClass(properties.getProperty("driverClass"));
        comboPooledDataSource.setJdbcUrl(properties.getProperty("jdbcUrl"));
        comboPooledDataSource.setUser(properties.getProperty("username"));
        comboPooledDataSource.setPassword(properties.getProperty("password"));
        //填充 configuration
        configuration.setDataSource(comboPooledDataSource);
        //mapper.xml解析: 拿到路径--字节输入流--dom4j进行解析
        List<Element> mapperList = rootElement.selectNodes("//mapper");
        for (Element element : mapperList) {
            String mapperPath = element.attributeValue("resource");
            InputStream resourceAsSteam = Resources.getResourceAsSteam(mapperPath);
            XMLMapperBuilder xmlMapperBuilder = new XMLMapperBuilder(configuration);
            xmlMapperBuilder.parse(resourceAsSteam);
        }
        return configuration;
    }
}

11.XMLMapperBuilder

package com.zou.config;

import com.zou.pojo.Configuration;
import com.zou.pojo.MappedStatement;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

import java.io.InputStream;
import java.util.List;

/**
 * @author: 邹祥发
 * @date: 2021/11/29 09:17
 */
public class XMLMapperBuilder {

    private final Configuration configuration;

    public XMLMapperBuilder(Configuration configuration) {
        this.configuration = configuration;
    }

    public void parse(InputStream inputStream) throws DocumentException {
        Document document = new SAXReader().read(inputStream);
        Element rootElement = document.getRootElement();
        String namespace = rootElement.attributeValue("namespace");
        List<Element> list = rootElement.selectNodes("//select");
        for (Element element : list) {
            String id = element.attributeValue("id");
            String resultType = element.attributeValue("resultType");
            String paramterType = element.attributeValue("paramterType");
            //sql语句
            String sqlText = element.getTextTrim();
            //封装 mappedStatement
            MappedStatement mappedStatement = new MappedStatement();
            mappedStatement.setId(id);
            mappedStatement.setResultType(resultType);
            mappedStatement.setParamterType(paramterType);
            mappedStatement.setSql(sqlText);
            //statementId
            String key = namespace + "." + id;
            //填充 configuration
            configuration.getMappedStatementMap().put(key, mappedStatement);
        }
    }
}

12.sqlSessionFactory 接⼝及DefaultSqlSessionFactory 实现类

package com.zou.sqlSession;

/**
 * @author: 邹祥发
 * @date: 2021/11/29 09:50
 */
public interface SqlSessionFactory {
    public SqlSession openSession();
}

package com.zou.sqlSession;

import com.zou.pojo.Configuration;

/**
 * @author: 邹祥发
 * @date: 2021/11/29 09:51
 */
public class DefaultSqlSessionFactory implements SqlSessionFactory {

    private final Configuration configuration;

    public DefaultSqlSessionFactory(Configuration configuration) {
        this.configuration = configuration;
    }

    @Override
    public SqlSession openSession() {
        return new DefaultSqlSession(configuration);
    }
}

13.sqlSession 接⼝及 DefaultSqlSession 实现类

package com.zou.sqlSession;

import java.util.List;

/**
 * @author: 邹祥发
 * @date: 2021/11/29 09:52
 */
public interface SqlSession {
    //查询所有
    public <E> List<E> selectList(String statementid, Object... params) throws Exception;

    //根据条件查询单个
    public <T> T selectOne(String statementid, Object... params) throws Exception;

    //为Dao接口生成代理实现类
    public <T> T getMapper(Class<?> mapperClass);
}

package com.zou.sqlSession;

import com.zou.pojo.Configuration;
import com.zou.pojo.MappedStatement;

import java.lang.reflect.*;
import java.util.List;

/**
 * @author: 邹祥发
 * @date: 2021/11/29 09:53
 */
public class DefaultSqlSession implements SqlSession {

    private final Configuration configuration;

    public DefaultSqlSession(Configuration configuration) {
        this.configuration = configuration;
    }

    @Override
    public <E> List<E> selectList(String statementid, Object... params) throws Exception {
        //将要去完成对simpleExecutor里的query方法的调用
        simpleExecutor simpleExecutor = new simpleExecutor();
        MappedStatement mappedStatement = configuration.getMappedStatementMap().get(statementid);
        List<Object> list = simpleExecutor.query(configuration, mappedStatement, params);
        return (List<E>) list;
    }

    @Override
    public <T> T selectOne(String statementid, Object... params) throws Exception {
        List<Object> objects = selectList(statementid, params);
        if (objects.size() == 1) {
            return (T) objects.get(0);
        } else {
            throw new RuntimeException("查询结果为空或者返回结果过多");
        }
    }

    @Override
    public <T> T getMapper(Class<?> mapperClass) {
        // 使用JDK动态代理来为Dao接口生成代理对象，并返回
        Object proxyInstance = Proxy.newProxyInstance(DefaultSqlSession.class.getClassLoader(), new Class[]{mapperClass}, new InvocationHandler() {
            @Override
            public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
                // 底层都还是去执行JDBC代码 //根据不同情况，来调用selctList或者selectOne
                // 准备参数 1：statmentid :sql语句的唯一标识：namespace.id= 接口全限定名.方法名
                // 方法名：findAll
                String methodName = method.getName();
                String className = method.getDeclaringClass().getName();
                String statementId = className + "." + methodName;
                // 准备参数2：params:args
                // 获取被调用方法的返回值类型
                Type genericReturnType = method.getGenericReturnType();
                // 判断是否进行了 泛型类型参数化
                if (genericReturnType instanceof ParameterizedType) {
                    return selectList(statementId, args);
                }
                return selectOne(statementId, args);
            }
        });
        return (T) proxyInstance;
    }
}

14.Executor

package com.zou.sqlSession;

import com.zou.pojo.Configuration;
import com.zou.pojo.MappedStatement;

import java.util.List;

/**
 * @author: 邹祥发
 * @date: 2021/11/29 09:55
 */
public interface Executor {
    public <E> List<E> query(Configuration configuration, MappedStatement mappedStatement, Object... params) throws Exception;
}

15.SimpleExecutor

package com.zou.sqlSession;

import com.zou.config.BoundSql;
import com.zou.pojo.Configuration;
import com.zou.pojo.MappedStatement;
import com.zou.utils.GenericTokenParser;
import com.zou.utils.ParameterMapping;
import com.zou.utils.ParameterMappingTokenHandler;

import java.beans.PropertyDescriptor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.util.ArrayList;
import java.util.List;

/**
 * @author: 邹祥发
 * @date: 2021/11/29 09:56
 */
public class simpleExecutor implements Executor {
    @Override                                                                                //user
    public <E> List<E> query(Configuration configuration, MappedStatement mappedStatement, Object... params) throws Exception {
        // 1. 注册驱动，获取连接
        Connection connection = configuration.getDataSource().getConnection();
        // 2. 获取sql语句 : select * from user where id = #{id} and username = #{username}
        //转换sql语句： select * from user where id = ? and username = ? ，转换的过程中，还需要对#{}里面的值进行解析存储
        String sql = mappedStatement.getSql();
        BoundSql boundSql = getBoundSql(sql);
        // 3.获取预处理对象：preparedStatement
        PreparedStatement preparedStatement = connection.prepareStatement(boundSql.getSqlText());
        // 4. 设置参数
        //获取到了参数的全路径
        String paramterType = mappedStatement.getParamterType();
        Class<?> paramtertypeClass = getClassType(paramterType);
        List<ParameterMapping> parameterMappingList = boundSql.getParameterMappingList();
        for (int i = 0; i < parameterMappingList.size(); i++) {
            ParameterMapping parameterMapping = parameterMappingList.get(i);
            String content = parameterMapping.getContent();
            //反射
            Field declaredField = paramtertypeClass.getDeclaredField(content);
            //暴力访问
            declaredField.setAccessible(true);
            Object o = declaredField.get(params[0]);
            preparedStatement.setObject(i + 1, o);
        }
        // 5. 执行sql
        ResultSet resultSet = preparedStatement.executeQuery();
        String resultType = mappedStatement.getResultType();
        Class<?> resultTypeClass = getClassType(resultType);
        ArrayList<Object> objects = new ArrayList<>();
        // 6. 封装返回结果集
        while (resultSet.next()) {
            Object o = resultTypeClass.newInstance();
            //元数据
            ResultSetMetaData metaData = resultSet.getMetaData();
            for (int i = 1; i <= metaData.getColumnCount(); i++) {
                // 字段名
                String columnName = metaData.getColumnName(i);
                // 字段的值
                Object value = resultSet.getObject(columnName);
                //使用反射或者内省，根据数据库表和实体的对应关系，完成封装
                PropertyDescriptor propertyDescriptor = new PropertyDescriptor(columnName, resultTypeClass);
                Method writeMethod = propertyDescriptor.getWriteMethod();
                writeMethod.invoke(o, value);
            }
            objects.add(o);
        }
        return (List<E>) objects;
    }

    private Class<?> getClassType(String paramterType) throws ClassNotFoundException {
        if (paramterType != null) {
            return Class.forName(paramterType);
        }
        return null;
    }

    /**
     * 完成对#{}的解析工作：1.将#{}使用？进行代替，2.解析出#{}里面的值进行存储
     *
     */
    private BoundSql getBoundSql(String sql) {
        //标记处理类：配置标记解析器来完成对占位符的解析处理工作
        ParameterMappingTokenHandler parameterMappingTokenHandler = new ParameterMappingTokenHandler();
        GenericTokenParser genericTokenParser = new GenericTokenParser("#{", "}", parameterMappingTokenHandler);
        //解析出来的sql
        String parseSql = genericTokenParser.parse(sql);
        //#{}里面解析出来的参数名称
        List<ParameterMapping> parameterMappings = parameterMappingTokenHandler.getParameterMappings();
        return new BoundSql(parseSql, parameterMappings);
    }
}

16.BoundSql

package com.zou.config;

import com.zou.utils.ParameterMapping;

import java.util.List;

/**
 * @author: 邹祥发
 * @date: 2021/11/29 10:02
 */
public class BoundSql {
    //解析过后的sql
    private String sqlText;
    private List<ParameterMapping> parameterMappingList;

    public BoundSql(String sqlText, List<ParameterMapping> parameterMappingList) {
        this.sqlText = sqlText;
        this.parameterMappingList = parameterMappingList;
    }

    public String getSqlText() {
        return sqlText;
    }

    public void setSqlText(String sqlText) {
        this.sqlText = sqlText;
    }

    public List<ParameterMapping> getParameterMappingList() {
        return parameterMappingList;
    }

    public void setParameterMappingList(List<ParameterMapping> parameterMappingList) {
        this.parameterMappingList = parameterMappingList;
    }
}

17.ParameterMapping

package com.zou.utils;

/**
 * @author: 邹祥发
 * @date: 2021/11/29 10:05
 */
public class ParameterMapping {
    private String content;
    public ParameterMapping(String content) {
        this.content = content;
    }

    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }
}

18.GenericTokenParser

package com.zou.utils;

/**
 * @author: 邹祥发
 * @date: 2021/11/29 10:07
 */
public class GenericTokenParser {

    private final String openToken; //开始标记
    private final String closeToken; //结束标记
    private final TokenHandler handler; //标记处理器

    public GenericTokenParser(String openToken, String closeToken, TokenHandler handler) {
        this.openToken = openToken;
        this.closeToken = closeToken;
        this.handler = handler;
    }

    /**
     * 解析${}和#{}
     *
     * @return 该方法主要实现了配置文件、脚本等片段中占位符的解析、处理工作，并返回最终需要的数据。
     * 其中，解析工作由该方法完成，处理工作是由处理器handler的handleToken()方法来实现
     */
    public String parse(String text) {
        // 验证参数问题，如果是null，就返回空字符串。
        if (text == null || text.isEmpty()) {
            return "";
        }
        // 下面继续验证是否包含开始标签，如果不包含，默认不是占位符，直接原样返回即可，否则继续执行。
        int start = text.indexOf(openToken, 0);
        if (start == -1) {
            return text;
        }

        // 把text转成字符数组src，并且定义默认偏移量offset=0、存储最终需要返回字符串的变量builder，
        // text变量中占位符对应的变量名expression。判断start是否大于-1(即text中是否存在openToken)，如果存在就执行下面代码
        char[] src = text.toCharArray();
        int offset = 0;
        final StringBuilder builder = new StringBuilder();
        StringBuilder expression = null;
        while (start > -1) {
            // 判断如果开始标记前如果有转义字符，就不作为openToken进行处理，否则继续处理
            if (start > 0 && src[start - 1] == '\\') {
                builder.append(src, offset, start - offset - 1).append(openToken);
                offset = start + openToken.length();
            } else {
                //重置expression变量，避免空指针或者老数据干扰。
                if (expression == null) {
                    expression = new StringBuilder();
                } else {
                    expression.setLength(0);
                }
                builder.append(src, offset, start - offset);
                offset = start + openToken.length();
                int end = text.indexOf(closeToken, offset);
                while (end > -1) {////存在结束标记时
                    if (end > offset && src[end - 1] == '\\') {//如果结束标记前面有转义字符时
                        // this close token is escaped. remove the backslash and continue.
                        expression.append(src, offset, end - offset - 1).append(closeToken);
                        offset = end + closeToken.length();
                        end = text.indexOf(closeToken, offset);
                    } else {//不存在转义字符，即需要作为参数进行处理
                        expression.append(src, offset, end - offset);
                        offset = end + closeToken.length();
                        break;
                    }
                }
                if (end == -1) {
                    // close token was not found.
                    builder.append(src, start, src.length - start);
                    offset = src.length;
                } else {
                    //首先根据参数的key（即expression）进行参数处理，返回?作为占位符
                    builder.append(handler.handleToken(expression.toString()));
                    offset = end + closeToken.length();
                }
            }
            start = text.indexOf(openToken, offset);
        }
        if (offset < src.length) {
            builder.append(src, offset, src.length - offset);
        }
        return builder.toString();
    }
}

19.TokenHandler

package com.zou.utils;

/**
 * @author: 邹祥发
 * @date: 2021/11/29 10:08
 */
public interface TokenHandler {
    String handleToken(String content);
}

20.ParameterMappingTokenHandler

package com.zou.utils;

import java.util.ArrayList;
import java.util.List;

/**
 * @author: 邹祥发
 * @date: 2021/11/29 10:08
 */
public class ParameterMappingTokenHandler implements TokenHandler {
    private List<ParameterMapping> parameterMappings = new ArrayList<ParameterMapping>();

    // context是参数名称 #{id} #{username}
    public String handleToken(String content) {
        parameterMappings.add(buildParameterMapping(content));
        return "?";
    }

    private ParameterMapping buildParameterMapping(String content) {
        return new ParameterMapping(content);
    }

    public List<ParameterMapping> getParameterMappings() {
        return parameterMappings;
    }

    public void setParameterMappings(List<ParameterMapping> parameterMappings) {
        this.parameterMappings = parameterMappings;
    }
}

21.在框架端先clear，再install。并在使用端引入maven坐标

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.zou</groupId>
    <artifactId>zdy-mabatis_test</artifactId>
    <version>1.0</version>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.encoding>UTF-8</maven.compiler.encoding>
        <java.version>1.8</java.version>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
    </properties>

    <!--引入自定义持久层框架的依赖-->
    <dependencies>
        <dependency>
            <groupId>com.zou</groupId>
            <artifactId>zdy-mybatis</artifactId>
            <version>1.0</version>
        </dependency>
    </dependencies>

</project>

22.编写log4j.properties日志文件

log4j.rootLogger=WARN, stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d %p [%c] - %m%n

23.编写测试类

package com.zou.test;

import com.zou.dao.IUserDao;
import com.zou.io.Resources;
import com.zou.pojo.User;
import com.zou.sqlSession.SqlSession;
import com.zou.sqlSession.SqlSessionFactory;
import com.zou.sqlSession.SqlSessionFactoryBuilder;
import org.junit.Test;

import java.io.InputStream;
import java.util.List;

/**
 * @author: 邹祥发
 * @date: 2021/11/29 10:17
 */
public class CustomTest {
    @Test
    public void test() throws Exception {
        InputStream resourceAsSteam = Resources.getResourceAsSteam("sqlMapConfig.xml");
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsSteam);
        SqlSession sqlSession = sqlSessionFactory.openSession();
        //调用
        User user = new User();
        user.setId(1);
        user.setUsername("小邹");
        IUserDao userDao = sqlSession.getMapper(IUserDao.class);
        List<User> userList = userDao.findAll();
        for (User users : userList) {
            System.out.println(users);
        }
    }
}

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最后编辑时间为: 2021/11/29 15:08:57