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 - @mbggenerated
This 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() {
// insert
String id = context.getStringAttribute("id");
// null
String 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");
// null
Integer timeout = context.getIntAttribute("timeout");
// null
String parameterMap = context.getStringAttribute("parameterMap");
// cn.vansky.schedule.time.menu.bo.Menu
String parameterType = context.getStringAttribute("parameterType");
// class cn.vansky.schedule.time.menu.bo.Menu
Class<?> parameterTypeClass = resolveClass(parameterType);
// null
String resultMap = context.getStringAttribute("resultMap");
// null
String resultType = context.getStringAttribute("resultType");
// null
String lang = context.getStringAttribute("lang");
// 获取默认的处理对象
// org.apache.ibatis.scripting.xmltags.XMLLanguageDriver
LanguageDriver langDriver = getLanguageDriver(lang);
// null
Class<?> resultTypeClass = resolveClass(resultType);
// null
String resultSetType = context.getStringAttribute("resultSetType");
// PREPARED
StatementType statementType = StatementType.valueOf(context.getStringAttribute("statementType", StatementType.PREPARED.toString()));
// null
ResultSetType resultSetTypeEnum = resolveResultSetType(resultSetType);
// insert
String nodeName = context.getNode().getNodeName();
// INSERT
SqlCommandType sqlCommandType = SqlCommandType.valueOf(nodeName.toUpperCase(Locale.ENGLISH));
// false
boolean isSelect = sqlCommandType == SqlCommandType.SELECT;
// true
boolean flushCache = context.getBooleanAttribute("flushCache", !isSelect);
// false
boolean useCache = context.getBooleanAttribute("useCache", isSelect);
// false
boolean resultOrdered = context.getBooleanAttribute("resultOrdered", false);
// Include Fragments before parsing
XMLIncludeTransformer 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);
// null
String resultSets = context.getStringAttribute("resultSets");
// null
String keyProperty = context.getStringAttribute("keyProperty");
// null
String keyColumn = context.getStringAttribute("keyColumn");
// org.apache.ibatis.executor.keygen.NoKeyGenerator
KeyGenerator keyGenerator;
// insert!selectKey
String keyStatementId = id + SelectKeyGenerator.SELECT_KEY_SUFFIX;
// cn.vansky.schedule.time.menu.dao.MenuMapper.insert!selectKey
keyStatementId = 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、for
List<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SqlNode
TextSqlNode 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、for
String nodeName = child.getNode().getNodeName();
// 获取动态标签处理器WhereHandler、ForEachHandler
NodeHandler 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SQLNode
handler.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Mapping
ParameterMappingTokenHandler 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ParameterMapping
String 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 - @mbggenerated
This 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。
原文：http://my.oschina.net/u/1269959/blog/523651