2019独角兽企业重金招聘Python工程师标准>>> 
本章中分析insert元素的解析。
1 配置文件
<insert id="insert" parameterType="cn.vansky.schedule.time.menu.bo.Menu"><!--WARNING - @mbggeneratedThis element is automatically generated by MyBatis Generator, do not modify.This element was generated on Fri Aug 14 16:08:36 CST 2015.-->insert into tb_menu (menu_name, menu_remark, menu_parent_id, menu_url, is_show, is_delete, operation_user_name, operation_time)values (#{menuName,jdbcType=VARCHAR}, #{menuRemark,jdbcType=VARCHAR}, #{menuParentId,jdbcType=INTEGER}, #{menuUrl,jdbcType=VARCHAR}, #{isShow,jdbcType=TINYINT}, #{isDelete,jdbcType=TINYINT}, #{operationUserName,jdbcType=VARCHAR}, #{operationTime,jdbcType=TIMESTAMP})
</insert>2 方法buildStatementFromContext
private void buildStatementFromContext(List<XNode> list) {if (configuration.getDatabaseId() != null) {buildStatementFromContext(list, configuration.getDatabaseId());}buildStatementFromContext(list, null);}private void buildStatementFromContext(List<XNode> list, String requiredDatabaseId) {for (XNode context : list) {// 对一个SQL进行解析final XMLStatementBuilder statementParser = new XMLStatementBuilder(configuration, builderAssistant, context, requiredDatabaseId);try {statementParser.parseStatementNode();} catch (IncompleteElementException e) {configuration.addIncompleteStatement(statementParser);}}
}上面是一个总的方法包括，insert、update、delete、select4中元素都会进入此方法。这里也会捕获一种异常，并把错误的解析放入Configuration(全局配置类)的Collection<XMLStatementBuilder> incompleteStatements = new LinkedList<XMLStatementBuilder>()。
3 方法parseStatementNode
public void parseStatementNode() {// insertString id = context.getStringAttribute("id");// nullString databaseId = context.getStringAttribute("databaseId");// 第一次检查这里是不通过的，直接跳过if (!databaseIdMatchesCurrent(id, databaseId, this.requiredDatabaseId)) return;// null Integer fetchSize = context.getIntAttribute("fetchSize");// nullInteger timeout = context.getIntAttribute("timeout");// nullString parameterMap = context.getStringAttribute("parameterMap");// cn.vansky.schedule.time.menu.bo.MenuString parameterType = context.getStringAttribute("parameterType");// class cn.vansky.schedule.time.menu.bo.MenuClass<?> parameterTypeClass = resolveClass(parameterType);// nullString resultMap = context.getStringAttribute("resultMap");// nullString resultType = context.getStringAttribute("resultType");// nullString lang = context.getStringAttribute("lang");// 获取默认的处理对象// org.apache.ibatis.scripting.xmltags.XMLLanguageDriverLanguageDriver langDriver = getLanguageDriver(lang);// nullClass<?> resultTypeClass = resolveClass(resultType);// nullString resultSetType = context.getStringAttribute("resultSetType");// PREPAREDStatementType statementType = StatementType.valueOf(context.getStringAttribute("statementType", StatementType.PREPARED.toString()));// nullResultSetType resultSetTypeEnum = resolveResultSetType(resultSetType);// insertString nodeName = context.getNode().getNodeName();// INSERTSqlCommandType sqlCommandType = SqlCommandType.valueOf(nodeName.toUpperCase(Locale.ENGLISH));// falseboolean isSelect = sqlCommandType == SqlCommandType.SELECT;// trueboolean flushCache = context.getBooleanAttribute("flushCache", !isSelect);// falseboolean useCache = context.getBooleanAttribute("useCache", isSelect);// falseboolean resultOrdered = context.getBooleanAttribute("resultOrdered", false);// Include Fragments before parsingXMLIncludeTransformer includeParser = new XMLIncludeTransformer(configuration, builderAssistant);// 解析<include refid="Base_Column_List" />includeParser.applyIncludes(context.getNode());// Parse selectKey after includes and remove them.processSelectKeyNodes(id, parameterTypeClass, langDriver);// 这里通过下面分析获取的SQL源（静态SQL源），因为没有动态标签SqlSource sqlSource = langDriver.createSqlSource(configuration, context, parameterTypeClass);// nullString resultSets = context.getStringAttribute("resultSets");// nullString keyProperty = context.getStringAttribute("keyProperty");// nullString keyColumn = context.getStringAttribute("keyColumn");// org.apache.ibatis.executor.keygen.NoKeyGeneratorKeyGenerator keyGenerator;// insert!selectKeyString keyStatementId = id + SelectKeyGenerator.SELECT_KEY_SUFFIX;// cn.vansky.schedule.time.menu.dao.MenuMapper.insert!selectKeykeyStatementId = builderAssistant.applyCurrentNamespace(keyStatementId, true);if (configuration.hasKeyGenerator(keyStatementId)) {keyGenerator = configuration.getKeyGenerator(keyStatementId);} else {keyGenerator = context.getBooleanAttribute("useGeneratedKeys",configuration.isUseGeneratedKeys() && SqlCommandType.INSERT.equals(sqlCommandType))? new Jdbc3KeyGenerator() : new NoKeyGenerator();}builderAssistant.addMappedStatement(id, sqlSource, statementType, sqlCommandType,fetchSize, timeout, parameterMap, parameterTypeClass, resultMap, resultTypeClass,resultSetTypeEnum, flushCache, useCache, resultOrdered, keyGenerator, keyProperty, keyColumn, databaseId, langDriver, resultSets);}4 方法XMLLanguageDriver.createSqlSource
public SqlSource createSqlSource(Configuration configuration, XNode script, Class<?> parameterType) {XMLScriptBuilder builder = new XMLScriptBuilder(configuration, script, parameterType);// 入参Class及节点解析return builder.parseScriptNode();
}5 方法XMLScriptBuilder.parseScriptNode
public SqlSource parseScriptNode() {// 解析动态标签，if、where、forList<SqlNode> contents = parseDynamicTags(context);// 所有动态标签集合类MixedSqlNode rootSqlNode = new MixedSqlNode(contents);SqlSource sqlSource = null;if (isDynamic) {sqlSource = new DynamicSqlSource(configuration, rootSqlNode);} else {sqlSource = new RawSqlSource(configuration, rootSqlNode, parameterType);}return sqlSource;
}6 方法XMLScriptBuilder.parseDynamicTags
private List<SqlNode> parseDynamicTags(XNode node) {List<SqlNode> contents = new ArrayList<SqlNode>();// 获取动态标签与内容列表NodeList children = node.getNode().getChildNodes();for (int i = 0; i < children.getLength(); i++) {XNode child = node.newXNode(children.item(i));// 内容if (child.getNode().getNodeType() == Node.CDATA_SECTION_NODE || child.getNode().getNodeType() == Node.TEXT_NODE) {String data = child.getStringBody("");// 内容SqlNodeTextSqlNode textSqlNode = new TextSqlNode(data);// 动态修改的内容if (textSqlNode.isDynamic()) {contents.add(textSqlNode);isDynamic = true;} else {// 静态内容contents.add(new StaticTextSqlNode(data));}} else if (child.getNode().getNodeType() == Node.ELEMENT_NODE) { // issue #628// 节点为元素，也就是动态标签where、if、forString nodeName = child.getNode().getNodeName();// 获取动态标签处理器WhereHandler、ForEachHandlerNodeHandler handler = nodeHandlers.get(nodeName);if (handler == null) {throw new BuilderException("Unknown element <" + nodeName + "> in SQL statement.");}// 处理器处理内容，并把处理的内容加入到SQLNodehandler.handleNode(child, contents);isDynamic = true;}}return contents;}方法5中有2中数据源DynamicSqlSource(动态SQL源)和RawSqlSource(静态SQL源)，动态SQL源就是包括where、if、for，静态SQL源就是只包括SQL语句，下面就简单分析一下2中SQL源。
7 RawSqlSource(静态SQL源)
public RawSqlSource(Configuration configuration, String sql, Class<?> parameterType) {SqlSourceBuilder sqlSourceParser = new SqlSourceBuilder(configuration);Class<?> clazz = parameterType == null ? Object.class : parameterType;sqlSource = sqlSourceParser.parse(sql, clazz, new HashMap<String, Object>());
}
public SqlSource parse(String originalSql, Class<?> parameterType, Map<String, Object> additionalParameters) {// 参数处理MappingParameterMappingTokenHandler handler = new ParameterMappingTokenHandler(configuration, parameterType, additionalParameters);GenericTokenParser parser = new GenericTokenParser("#{", "}", handler);// 解析XML中的SQL语句，#{menuName,jdbcType=VARCHAR}，转换成？及对应的处理类型ParameterMappingString sql = parser.parse(originalSql);return new StaticSqlSource(configuration, sql, handler.getParameterMappings());
}这里直接解析并生成StaticSqlSource，包括SQL语句及对应的处理类型。
7.1 ParameterMapping对应的menuName
/** 全局配置类 */
private Configuration configuration;
/** menuName */
private String property;
/** IN:输入 */
private ParameterMode mode;
/** class java.lang.String */
private Class<?> javaType = Object.class;
/** VARCHAR */
private JdbcType jdbcType;
/** null */
private Integer numericScale;
/** StringTypeHandler */
private TypeHandler<?> typeHandler;
/** null */
private String resultMapId;
/** null */
private String jdbcTypeName;
/** null */
private String expression;8 DynamicSqlSource(动态SQL源)
public DynamicSqlSource(Configuration configuration, SqlNode rootSqlNode) {this.configuration = configuration;this.rootSqlNode = rootSqlNode;
}很明显这里没有进行生成SQL，那就是在具体获取SQL时进行生成SQL
9 方法addMappedStatement
此方法只是赋值，没有什么特殊处理，所以此方法不在分析，可以自行研究。
总结
附上图片MappedStatement属性值
下面给出动态SQL源的MappedStatement属性值
<insert id="insertSelective" parameterType="cn.vansky.schedule.time.menu.bo.Menu"><!--WARNING - @mbggeneratedThis element is automatically generated by MyBatis Generator, do not modify.This element was generated on Fri Aug 14 16:08:36 CST 2015.-->insert into tb_menu<trim prefix="(" suffix=")" suffixOverrides=","><if test="menuName != null">menu_name,</if><if test="menuRemark != null">menu_remark,</if><if test="menuParentId != null">menu_parent_id,</if><if test="menuUrl != null">menu_url,</if><if test="isShow != null">is_show,</if><if test="isDelete != null">is_delete,</if><if test="operationUserName != null">operation_user_name,</if><if test="operationTime != null">operation_time,</if></trim><trim prefix="values (" suffix=")" suffixOverrides=","><if test="menuName != null">#{menuName,jdbcType=VARCHAR},</if><if test="menuRemark != null">#{menuRemark,jdbcType=VARCHAR},</if><if test="menuParentId != null">#{menuParentId,jdbcType=INTEGER},</if><if test="menuUrl != null">#{menuUrl,jdbcType=VARCHAR},</if><if test="isShow != null">#{isShow,jdbcType=TINYINT},</if><if test="isDelete != null">#{isDelete,jdbcType=TINYINT},</if><if test="operationUserName != null">#{operationUserName,jdbcType=VARCHAR},</if><if test="operationTime != null">#{operationTime,jdbcType=TIMESTAMP},</if></trim>
</insert>
其实这里属性都差不多，主要是SqlSource不一样，那么下来就看它的属性。
