添加TypeHandler处理器

pom.xml

@@ -29,6 +29,11 @@
             <artifactId>HikariCP</artifactId>
             <version>3.4.5</version>
         </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>3.14.0</version>
+        </dependency>
     </dependencies>
 
     <build>

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

@@ -14,6 +14,7 @@
 import org.apache.ibatis.executor.statement.StatementHandler;
 import org.apache.ibatis.mapping.BoundSql;
 import org.apache.ibatis.mapping.MappedStatement;
+import org.apache.ibatis.type.TypeHandlerRegistry;
 
 /**
  * mybatis全局配置类
@@ -27,6 +28,7 @@ public class Configuration {
     private final MapperRegistry mapperRegistry = new MapperRegistry(this);
     private final Set<String> loadedResources = new HashSet<>();
     private final Map<String, MappedStatement> mappedStatements = new HashMap<>();
+    private final TypeHandlerRegistry typeHandlerRegistry = new TypeHandlerRegistry();
 
     public Configuration() {
     }
@@ -74,4 +76,8 @@ public void setDataSource(DataSource dataSource) {
     public StatementHandler newStatementHandler(Executor executor, MappedStatement mappedStatement, Object parameterObject, BoundSql boundSql) {
         return new PrepareStatementHandler(executor, mappedStatement, parameterObject, boundSql);
     }
+
+    public TypeHandlerRegistry getTypeHandlerRegistry() {
+        return typeHandlerRegistry;
+    }
 }

src/main/java/org/apache/ibatis/type/BaseTypeHandler.java

@@ -0,0 +1,31 @@
+package org.apache.ibatis.type;
+
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+import java.sql.Types;
+import java.util.Objects;
+
+/**
+ * @author furious 2024/4/9
+ */
+public abstract class BaseTypeHandler<T> implements TypeHandler<T> {
+
+    @Override
+    public void setParameter(PreparedStatement ps, int i, T parameter) throws SQLException {
+        if (Objects.isNull(parameter)) {
+            ps.setNull(i, Types.NULL);
+            return;
+        }
+        setNonNullParameter(ps, i, parameter);
+    }
+
+    /**
+     * 设置非空值
+     *
+     * @param ps        PreparedStatement
+     * @param i         1开始
+     * @param parameter 参数值
+     * @throws SQLException SQLException
+     */
+    protected abstract void setNonNullParameter(PreparedStatement ps, int i, T parameter) throws SQLException;
+}

src/main/java/org/apache/ibatis/type/IntegerTypeHandler.java

@@ -0,0 +1,14 @@
+package org.apache.ibatis.type;
+
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+
+/**
+ * @author furious 2024/4/9
+ */
+public class IntegerTypeHandler extends BaseTypeHandler<Integer> {
+    @Override
+    protected void setNonNullParameter(PreparedStatement ps, int i, Integer parameter) throws SQLException {
+        ps.setInt(i, parameter);
+    }
+}

src/main/java/org/apache/ibatis/type/ObjectTypeHandler.java

@@ -0,0 +1,14 @@
+package org.apache.ibatis.type;
+
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+
+/**
+ * @author furious 2024/4/9
+ */
+public class ObjectTypeHandler extends BaseTypeHandler<Object> {
+    @Override
+    protected void setNonNullParameter(PreparedStatement ps, int i, Object parameter) throws SQLException {
+        ps.setObject(i, parameter);
+    }
+}

src/main/java/org/apache/ibatis/type/StringTypeHandler.java

@@ -0,0 +1,14 @@
+package org.apache.ibatis.type;
+
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+
+/**
+ * @author furious 2024/4/9
+ */
+public class StringTypeHandler extends BaseTypeHandler<String> {
+    @Override
+    protected void setNonNullParameter(PreparedStatement ps, int i, String parameter) throws SQLException {
+        ps.setString(i, parameter);
+    }
+}

src/main/java/org/apache/ibatis/type/TypeHandler.java

@@ -0,0 +1,14 @@
+package org.apache.ibatis.type;
+
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+
+/**
+ * 参数类型处理接口
+ *
+ * @author furious 2024/4/9
+ */
+public interface TypeHandler<T> {
+
+    void setParameter(PreparedStatement ps, int i, T parameter) throws SQLException;
+}

src/main/java/org/apache/ibatis/type/TypeHandlerRegistry.java

@@ -0,0 +1,35 @@
+package org.apache.ibatis.type;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * @author furious 2024/4/9
+ */
+public class TypeHandlerRegistry {
+
+    private final TypeHandler<Object> unknownTypeHandler = new UnknownTypeHandler(this);
+    private final Map<Class<?>, TypeHandler<?>> allTypeHandlersMap = new HashMap<>();
+
+    public TypeHandlerRegistry() {
+        register(String.class, new StringTypeHandler());
+
+        register(Integer.class, new IntegerTypeHandler());
+        register(int.class, new IntegerTypeHandler());
+
+        register(Object.class, unknownTypeHandler);
+    }
+
+    public <T> void register(Class<T> javaType, TypeHandler<? extends T> typeHandler) {
+        allTypeHandlersMap.put(javaType, typeHandler);
+    }
+
+    @SuppressWarnings("unchecked")
+    public <T> TypeHandler<T> getTypeHandler(Class<T> type) {
+        return (TypeHandler<T>) allTypeHandlersMap.get(type);
+    }
+
+    public TypeHandler<Object> getUnknownTypeHandler() {
+        return unknownTypeHandler;
+    }
+}

src/main/java/org/apache/ibatis/type/UnknownTypeHandler.java

@@ -0,0 +1,29 @@
+package org.apache.ibatis.type;
+
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+import java.util.Objects;
+
+/**
+ * @author furious 2024/4/9
+ */
+public class UnknownTypeHandler extends BaseTypeHandler<Object> {
+
+    private static final ObjectTypeHandler OBJECT_TYPE_HANDLER = new ObjectTypeHandler();
+
+    private final TypeHandlerRegistry typeHandlerRegistry;
+
+    public UnknownTypeHandler(TypeHandlerRegistry typeHandlerRegistry) {
+        this.typeHandlerRegistry = typeHandlerRegistry;
+    }
+
+    @Override
+    @SuppressWarnings({"rawtypes", "unchecked"})
+    protected void setNonNullParameter(PreparedStatement ps, int i, Object parameter) throws SQLException {
+        TypeHandler handler = typeHandlerRegistry.getTypeHandler(parameter.getClass());
+        if (Objects.isNull(handler) || handler instanceof UnknownTypeHandler) {
+            handler = OBJECT_TYPE_HANDLER;
+        }
+        handler.setParameter(ps, i, parameter);
+    }
+}