注册mapper接口

README.md

@@ -1,3 +1,4 @@
 # mini-mybatis
 该项目是mybatis的mini版本，包含动态SQL，参数绑定，结果集处理，以及插件支持等核心功能，写mini-mybatis的初衷是想参照现有mybatis的功能，自己从0到1实现一个简化版，同时也希望帮助其他人熟悉mybatis的设计思想以及源码理解，为降低代码复杂度，该项目主要以实现核心功能为主，不会太注重性能以及线程安全等问题。该项目采用一步一步（step-by-step）的方式完善功能，每一个小功能模块使用一个独立的分支，分支前缀带有递增序号，序号由小到大表示功能的完善程度。
 # 功能模块
+[1.注册Mapper接口](https://github.com/FuriousPws002/mini-mybatis/wiki/1.%E6%B3%A8%E5%86%8CMapper%E6%8E%A5%E5%8F%A3 "Markdown")

pom.xml

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+<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.furious</groupId>
+    <artifactId>mini-mybatis</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+
+    <name>mini-mybatis</name>
+    <description>mini-mybatis</description>
+    <properties>
+        <java.version>8</java.version>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.13.2</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>8</source>
+                    <target>8</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+</project>

src/main/java/org/apache/ibatis/binding/BindingException.java

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+package org.apache.ibatis.binding;
+
+/**
+ * @author furious 2024/4/3
+ */
+public class BindingException extends RuntimeException {
+
+    public BindingException() {
+        super();
+    }
+
+    public BindingException(String message) {
+        super(message);
+    }
+
+    public BindingException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+    public BindingException(Throwable cause) {
+        super(cause);
+    }
+
+    protected BindingException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {
+        super(message, cause, enableSuppression, writableStackTrace);
+    }
+}

src/main/java/org/apache/ibatis/binding/MapperProxy.java

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+package org.apache.ibatis.binding;
+
+import java.lang.reflect.InvocationHandler;
+import java.lang.reflect.Method;
+
+import org.apache.ibatis.session.SqlSession;
+
+/**
+ * @author furious 2024/4/3
+ */
+public class MapperProxy<T> implements InvocationHandler {
+
+    private final SqlSession sqlSession;
+    private final Class<T> mapperInterface;
+
+    public MapperProxy(SqlSession sqlSession, Class<T> mapperInterface) {
+        this.sqlSession = sqlSession;
+        this.mapperInterface = mapperInterface;
+    }
+
+    @Override
+    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
+        return null;
+    }
+}

src/main/java/org/apache/ibatis/binding/MapperProxyFactory.java

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+package org.apache.ibatis.binding;
+
+import java.lang.reflect.InvocationHandler;
+import java.lang.reflect.Proxy;
+
+import org.apache.ibatis.session.SqlSession;
+
+/**
+ * @author furious 2024/4/3
+ */
+public class MapperProxyFactory<T> {
+
+    private final Class<T> mapperInterface;
+
+    public MapperProxyFactory(Class<T> mapperInterface) {
+        this.mapperInterface = mapperInterface;
+    }
+
+    public <T> T newInstance(SqlSession sqlSession) {
+        InvocationHandler handler = new MapperProxy(sqlSession, mapperInterface);
+        return (T) Proxy.newProxyInstance(mapperInterface.getClassLoader(), new Class[]{mapperInterface}, handler);
+    }
+}

src/main/java/org/apache/ibatis/binding/MapperRegistry.java

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+package org.apache.ibatis.binding;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
+
+import org.apache.ibatis.session.Configuration;
+import org.apache.ibatis.session.SqlSession;
+
+/**
+ * @author furious 2024/4/3
+ */
+public class MapperRegistry {
+
+    private final Configuration config;
+    private final Map<Class<?>, MapperProxyFactory<?>> knownMappers = new HashMap<>();
+
+    public MapperRegistry(Configuration config) {
+        this.config = config;
+    }
+
+    public <T> boolean hasMapper(Class<T> type) {
+        return knownMappers.containsKey(type);
+    }
+
+    public <T> void addMapper(Class<T> type) {
+        //不是接口不支持，直接返回
+        if (!type.isInterface() || hasMapper(type)) {
+            return;
+        }
+        knownMappers.put(type, new MapperProxyFactory<>(type));
+    }
+
+    public <T> T getMapper(Class<T> type, SqlSession sqlSession) {
+        MapperProxyFactory<?> mapperProxyFactory = knownMappers.get(type);
+        if (Objects.isNull(mapperProxyFactory)) {
+            throw new BindingException(type + " type is not exist");
+        }
+        return mapperProxyFactory.newInstance(sqlSession);
+    }
+}

src/main/java/org/apache/ibatis/session/Configuration.java

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+package org.apache.ibatis.session;
+
+import org.apache.ibatis.binding.MapperRegistry;
+
+/**
+ * mybatis全局配置类
+ *
+ * @author furious 2024/4/3
+ */
+public class Configuration {
+
+    private final MapperRegistry mapperRegistry = new MapperRegistry(this);
+
+    public Configuration() {
+    }
+
+    public <T> void addMapper(Class<T> type) {
+        mapperRegistry.addMapper(type);
+    }
+
+    public <T> T getMapper(Class<T> type, SqlSession sqlSession) {
+        return mapperRegistry.getMapper(type, sqlSession);
+    }
+}

src/main/java/org/apache/ibatis/session/SqlSession.java

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+package org.apache.ibatis.session;
+
+import java.io.Closeable;
+
+/**
+ * @author furious 2024/3/29
+ */
+public interface SqlSession extends Closeable {
+
+    Configuration getConfiguration();
+
+    <T> T getMapper(Class<T> type);
+
+}

src/main/java/org/apache/ibatis/session/defaults/DefaultSqlSession.java

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+package org.apache.ibatis.session.defaults;
+
+import java.io.IOException;
+
+import org.apache.ibatis.session.Configuration;
+import org.apache.ibatis.session.SqlSession;
+
+/**
+ * @author furious 2024/4/3
+ */
+public class DefaultSqlSession implements SqlSession {
+
+    private final Configuration configuration;
+
+    public DefaultSqlSession(Configuration configuration) {
+        this.configuration = configuration;
+    }
+
+    @Override
+    public Configuration getConfiguration() {
+        return configuration;
+    }
+
+    @Override
+    public <T> T getMapper(Class<T> type) {
+        return configuration.getMapper(type, this);
+    }
+
+    @Override
+    public void close() throws IOException {
+
+    }
+}

src/test/java/org/apache/ibatis/binding/MapperRegistryTest.java

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+package org.apache.ibatis.binding;
+
+import org.apache.ibatis.dao.UserMapper;
+import org.apache.ibatis.session.Configuration;
+import org.apache.ibatis.session.SqlSession;
+import org.apache.ibatis.session.defaults.DefaultSqlSession;
+import org.junit.Assert;
+import org.junit.Test;
+
+/**
+ * @author furious 2024/4/3
+ */
+public class MapperRegistryTest {
+
+    @Test
+    public void test() {
+        Configuration configuration = new Configuration();
+        configuration.addMapper(UserMapper.class);
+        SqlSession sqlSession = new DefaultSqlSession(configuration);
+        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
+        Assert.assertNotNull(userMapper);
+    }
+}

src/test/java/org/apache/ibatis/dao/UserMapper.java

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+package org.apache.ibatis.dao;
+
+/**
+ * @author furious 2024/4/3
+ */
+public interface UserMapper {
+}