解析xml配置时，添加查询结果集resultType

FuriousPws002 · Apr 11, 2024 · 001fe00 · 001fe00
1 parent f3bb54f
commit 001fe00
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diff --git a/src/main/java/org/apache/ibatis/builder/BaseBuilder.java b/src/main/java/org/apache/ibatis/builder/BaseBuilder.java
@@ -1,5 +1,8 @@
 package org.apache.ibatis.builder;
 
+import java.util.Objects;
+
+import org.apache.commons.lang3.ClassUtils;
 import org.apache.ibatis.session.Configuration;
 
 /**
@@ -16,4 +19,16 @@ public BaseBuilder(Configuration configuration) {
     public Configuration getConfiguration() {
         return configuration;
     }
+
+    @SuppressWarnings("unchecked")
+    protected <T> Class<? extends T> resolveClass(String className) {
+        if (Objects.isNull(className)) {
+            return null;
+        }
+        try {
+            return (Class<? extends T>) ClassUtils.getClass(className);
+        } catch (Exception e) {
+            throw new BuilderException(e);
+        }
+    }
 }
diff --git a/src/main/java/org/apache/ibatis/builder/MapperBuilderAssistant.java b/src/main/java/org/apache/ibatis/builder/MapperBuilderAssistant.java
@@ -1,7 +1,10 @@
 package org.apache.ibatis.builder;
 
 
+import java.util.Objects;
+
 import org.apache.ibatis.mapping.MappedStatement;
+import org.apache.ibatis.mapping.ResultMap;
 import org.apache.ibatis.mapping.SqlCommandType;
 import org.apache.ibatis.mapping.SqlSource;
 import org.apache.ibatis.session.Configuration;
@@ -30,4 +33,21 @@ public void addMappedStatement(String id, SqlCommandType sqlCommandType, SqlSour
                 .build();
         configuration.addMappedStatement(statement);
     }
+
+    public void addMappedStatement(String id, SqlCommandType sqlCommandType, SqlSource sqlSource, Class<?> resultTypeClass) {
+        id = currentNamespace + "." + id;
+        MappedStatement statement = new MappedStatement.Builder(configuration, id, sqlSource, sqlCommandType)
+                .resource(resource)
+                .resultMap(getStatementResultMap(resultTypeClass))
+                .build();
+        configuration.addMappedStatement(statement);
+    }
+
+    private ResultMap getStatementResultMap(Class<?> resultType) {
+        if (Objects.isNull(resultType)) {
+            return null;
+        }
+        return new ResultMap(configuration, resultType);
+    }
+
 }
diff --git a/src/main/java/org/apache/ibatis/builder/xml/XMLStatementBuilder.java b/src/main/java/org/apache/ibatis/builder/xml/XMLStatementBuilder.java
@@ -2,6 +2,7 @@
 
 import java.util.Locale;
 
+import org.apache.commons.lang3.ClassUtils;
 import org.apache.ibatis.builder.BaseBuilder;
 import org.apache.ibatis.builder.MapperBuilderAssistant;
 import org.apache.ibatis.builder.StaticSqlSource;
@@ -36,6 +37,8 @@ public void parseStatementNode() {
         String nodeName = context.getName();
         SqlCommandType sqlCommandType = SqlCommandType.valueOf(nodeName.toUpperCase(Locale.ENGLISH));
         SqlSource sqlSource = configuration.getLanguageDriver().createSqlSource(configuration, context, null);
-        builderAssistant.addMappedStatement(id, sqlCommandType, sqlSource);
+        String resultType = context.getAttribute("resultType");
+        Class<?> resultTypeClass = resolveClass(resultType);
+        builderAssistant.addMappedStatement(id, sqlCommandType, sqlSource,resultTypeClass);
     }
 }
diff --git a/src/main/java/org/apache/ibatis/executor/result/ResultMapException.java b/src/main/java/org/apache/ibatis/executor/result/ResultMapException.java
@@ -0,0 +1,27 @@
+package org.apache.ibatis.executor.result;
+
+/**
+ * @author furious 2024/4/11
+ */
+public class ResultMapException extends RuntimeException{
+
+    public ResultMapException() {
+        super();
+    }
+
+    public ResultMapException(String message) {
+        super(message);
+    }
+
+    public ResultMapException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+    public ResultMapException(Throwable cause) {
+        super(cause);
+    }
+
+    protected ResultMapException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {
+        super(message, cause, enableSuppression, writableStackTrace);
+    }
+}
diff --git a/src/main/java/org/apache/ibatis/executor/resultset/ResultSetHandler.java b/src/main/java/org/apache/ibatis/executor/resultset/ResultSetHandler.java
@@ -0,0 +1,13 @@
+package org.apache.ibatis.executor.resultset;
+
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.List;
+
+/**
+ * @author furious 2024/4/11
+ */
+public interface ResultSetHandler {
+
+    <T> List<T> handleResultSets(Statement stmt) throws SQLException;
+}
diff --git a/src/main/java/org/apache/ibatis/executor/resultset/ResultSetWrapper.java b/src/main/java/org/apache/ibatis/executor/resultset/ResultSetWrapper.java
@@ -0,0 +1,38 @@
+package org.apache.ibatis.executor.resultset;
+
+import java.sql.ResultSet;
+import java.sql.ResultSetMetaData;
+import java.sql.SQLException;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.apache.ibatis.session.Configuration;
+import org.apache.ibatis.type.TypeHandler;
+import org.apache.ibatis.type.TypeHandlerRegistry;
+
+/**
+ * @author furious 2024/4/11
+ */
+public class ResultSetWrapper {
+
+    private final ResultSet resultSet;
+    private final TypeHandlerRegistry typeHandlerRegistry;
+    private final List<String> columnLabels = new ArrayList<>();
+    private final List<String> classNames = new ArrayList<>();
+    private final List<Integer> jdbcTypes = new ArrayList<>();
+
+    public ResultSetWrapper(ResultSet rs, Configuration configuration) throws SQLException {
+        this.resultSet = rs;
+        this.typeHandlerRegistry = configuration.getTypeHandlerRegistry();
+        ResultSetMetaData metaData = rs.getMetaData();
+        int columnCount = metaData.getColumnCount();
+        for (int i = 1; i <= columnCount; i++) {
+            columnLabels.add(metaData.getColumnLabel(i));
+            classNames.add(metaData.getColumnClassName(i));
+            jdbcTypes.add(metaData.getColumnType(i));
+        }
+    }
+
+}
diff --git a/src/main/java/org/apache/ibatis/mapping/MappedStatement.java b/src/main/java/org/apache/ibatis/mapping/MappedStatement.java
@@ -12,6 +12,7 @@ public class MappedStatement {
     private String id;
     private SqlSource sqlSource;
     private SqlCommandType sqlCommandType;
+    private ResultMap resultMap;
 
     public String getId() {
         return id;
@@ -45,6 +46,11 @@ public Builder resource(String resource) {
             return this;
         }
 
+        public Builder resultMap(ResultMap resultMap) {
+            mappedStatement.resultMap = resultMap;
+            return this;
+        }
+
         public MappedStatement build() {
             return mappedStatement;
         }

diff --git a/src/main/java/org/apache/ibatis/mapping/ResultMap.java b/src/main/java/org/apache/ibatis/mapping/ResultMap.java
@@ -0,0 +1,39 @@
+package org.apache.ibatis.mapping;
+
+import org.apache.ibatis.session.Configuration;
+
+/**
+ * @author furious 2024/4/11
+ */
+public class ResultMap {
+
+    private Configuration configuration;
+    /**
+     * select标签中的resultType
+     */
+    private Class<?> type;
+
+    public ResultMap() {
+    }
+
+    public ResultMap(Configuration configuration, Class<?> type) {
+        this.configuration = configuration;
+        this.type = type;
+    }
+
+    public Configuration getConfiguration() {
+        return configuration;
+    }
+
+    public void setConfiguration(Configuration configuration) {
+        this.configuration = configuration;
+    }
+
+    public Class<?> getType() {
+        return type;
+    }
+
+    public void setType(Class<?> type) {
+        this.type = type;
+    }
+}
diff --git a/src/main/java/org/apache/ibatis/type/BaseTypeHandler.java b/src/main/java/org/apache/ibatis/type/BaseTypeHandler.java
@@ -1,10 +1,13 @@
 package org.apache.ibatis.type;
 
 import java.sql.PreparedStatement;
+import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.sql.Types;
 import java.util.Objects;
 
+import org.apache.ibatis.executor.result.ResultMapException;
+
 /**
  * @author furious 2024/4/9
  */
@@ -19,6 +22,15 @@ public void setParameter(PreparedStatement ps, int i, T parameter) throws SQLExc
         setNonNullParameter(ps, i, parameter);
     }
 
+    @Override
+    public T getResult(ResultSet rs, String columnLabel) throws SQLException {
+        try {
+            return getNullableResult(rs, columnLabel);
+        } catch (Exception e) {
+            throw new ResultMapException(e);
+        }
+    }
+
     /**
      * 设置非空值
      *
@@ -28,4 +40,13 @@ public void setParameter(PreparedStatement ps, int i, T parameter) throws SQLExc
      * @throws SQLException SQLException
      */
     protected abstract void setNonNullParameter(PreparedStatement ps, int i, T parameter) throws SQLException;
+
+    /**
+     * 获取ResultSet中指定列的值
+     *
+     * @param rs          ResultSet
+     * @param columnLabel as别名值，无as时就是列名
+     * @return 获取值
+     */
+    protected abstract T getNullableResult(ResultSet rs, String columnLabel) throws SQLException;
 }
diff --git a/src/main/java/org/apache/ibatis/type/IntegerTypeHandler.java b/src/main/java/org/apache/ibatis/type/IntegerTypeHandler.java
@@ -1,6 +1,7 @@
 package org.apache.ibatis.type;
 
 import java.sql.PreparedStatement;
+import java.sql.ResultSet;
 import java.sql.SQLException;
 
 /**
@@ -11,4 +12,9 @@ public class IntegerTypeHandler extends BaseTypeHandler<Integer> {
     protected void setNonNullParameter(PreparedStatement ps, int i, Integer parameter) throws SQLException {
         ps.setInt(i, parameter);
     }
+
+    @Override
+    protected Integer getNullableResult(ResultSet rs, String columnLabel) throws SQLException {
+        return rs.getInt(columnLabel);
+    }
 }
diff --git a/src/main/java/org/apache/ibatis/type/ObjectTypeHandler.java b/src/main/java/org/apache/ibatis/type/ObjectTypeHandler.java
@@ -1,6 +1,7 @@
 package org.apache.ibatis.type;
 
 import java.sql.PreparedStatement;
+import java.sql.ResultSet;
 import java.sql.SQLException;
 
 /**
@@ -11,4 +12,9 @@ public class ObjectTypeHandler extends BaseTypeHandler<Object> {
     protected void setNonNullParameter(PreparedStatement ps, int i, Object parameter) throws SQLException {
         ps.setObject(i, parameter);
     }
+
+    @Override
+    protected Object getNullableResult(ResultSet rs, String columnLabel) throws SQLException {
+        return rs.getObject(columnLabel);
+    }
 }
diff --git a/src/main/java/org/apache/ibatis/type/StringTypeHandler.java b/src/main/java/org/apache/ibatis/type/StringTypeHandler.java
@@ -1,6 +1,7 @@
 package org.apache.ibatis.type;
 
 import java.sql.PreparedStatement;
+import java.sql.ResultSet;
 import java.sql.SQLException;
 
 /**
@@ -11,4 +12,9 @@ public class StringTypeHandler extends BaseTypeHandler<String> {
     protected void setNonNullParameter(PreparedStatement ps, int i, String parameter) throws SQLException {
         ps.setString(i, parameter);
     }
+
+    @Override
+    protected String getNullableResult(ResultSet rs, String columnLabel) throws SQLException {
+        return rs.getString(columnLabel);
+    }
 }
diff --git a/src/main/java/org/apache/ibatis/type/TypeHandler.java b/src/main/java/org/apache/ibatis/type/TypeHandler.java
@@ -1,6 +1,7 @@
 package org.apache.ibatis.type;
 
 import java.sql.PreparedStatement;
+import java.sql.ResultSet;
 import java.sql.SQLException;
 
 /**
@@ -11,4 +12,6 @@
 public interface TypeHandler<T> {
 
     void setParameter(PreparedStatement ps, int i, T parameter) throws SQLException;
+
+    T getResult(ResultSet rs, String columnLabel) throws SQLException;
 }
diff --git a/src/main/java/org/apache/ibatis/type/UnknownTypeHandler.java b/src/main/java/org/apache/ibatis/type/UnknownTypeHandler.java
@@ -1,9 +1,13 @@
 package org.apache.ibatis.type;
 
 import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.ResultSetMetaData;
 import java.sql.SQLException;
 import java.util.Objects;
 
+import org.apache.commons.lang3.ClassUtils;
+
 /**
  * @author furious 2024/4/9
  */
@@ -26,4 +30,34 @@ protected void setNonNullParameter(PreparedStatement ps, int i, Object parameter
         }
         handler.setParameter(ps, i, parameter);
     }
+
+    @Override
+    protected Object getNullableResult(ResultSet rs, String columnLabel) throws SQLException {
+        ResultSetMetaData metaData = rs.getMetaData();
+        int columnCount = metaData.getColumnCount();
+        int columnIndex = -1;
+        for (int i = 1; i < columnCount; i++) {
+            if (Objects.equals(metaData.getColumnLabel(i), columnLabel)) {
+                columnIndex = i;
+                break;
+            }
+        }
+
+        TypeHandler<?> handler = null;
+        if (columnIndex != -1) {
+            handler = typeHandlerRegistry.getTypeHandler(safeGetClassForColumn(metaData, columnIndex));
+        }
+        if (handler == null || handler instanceof UnknownTypeHandler) {
+            handler = OBJECT_TYPE_HANDLER;
+        }
+        return handler.getResult(rs, columnLabel);
+    }
+
+    private Class<?> safeGetClassForColumn(ResultSetMetaData metaData, Integer columnIndex) {
+        try {
+            return ClassUtils.getClass(metaData.getColumnClassName(columnIndex));
+        } catch (Exception e) {
+            return null;
+        }
+    }
 }