回到XMLMapperBuilder的parse方法
public void org.apache.ibatis.builder.xml.XMLMapperBuilder.parse() {
if (!configuration.isResourceLoaded(resource)) {
//解析配置
configurationElement(parser.evalNode("/mapper"));
//记录已被加载mapper资源
configuration.addLoadedResource(resource);
//构建mapper代理
bindMapperForNamespace();
}
//继续解析那些还未解析的映射，缓存引用，语句
//解析的方法在第二节已经分析过，是一样的，所以此处不再赘述
parsePendingResultMaps();
parsePendingChacheRefs();
parsePendingStatements();
}
构建mapper代理
private void org.apache.ibatis.builder.xml.XMLMapperBuilder.bindMapperForNamespace() {
//获取namespace
String namespace = builderAssistant.getCurrentNamespace();
if (namespace != null) {
Class<?> boundType = null;
try {
//加载mapper接口
boundType = Resources.classForName(namespace);
} catch (ClassNotFoundException e) {
//如果没有，忽略，应为这个namespace不一定要是mapper接口
//ignore, bound type is not required
}
//如果不为空
if (boundType != null) {
//如果没有注册这个mapper接口
if (!configuration.hasMapper(boundType)) {
// Spring may not know the real resource name so we set a flag
// to prevent loading again this resource from the mapper interface
// look at MapperAnnotationBuilder#loadXmlResource
//记录这个namespace的mapper接口已被加载
configuration.addLoadedResource("namespace:" + namespace);
//注册mapper接口
configuration.addMapper(boundType);
}
}
}
}
注册mapper接口
public <T> void org.apache.ibatis.session.Configuration.addMapper(Class<T> type) {
//(*1*)
mapperRegistry.addMapper(type);
}
//(*1*)
public <T> void addMapper(Class<T> type) {
//对应的类需要是接口，不是接口忽略
if (type.isInterface()) {
//如果已经存在，抛错
if (hasMapper(type)) {
throw new BindingException("Type " + type + " is already known to the MapperRegistry.");
}
boolean loadCompleted = false;
try {
//注册,type -> MapperProxyFactory
knownMappers.put(type, new MapperProxyFactory<T>(type));
// It's important that the type is added before the parser is run
// otherwise the binding may automatically be attempted by the
// mapper parser. If the type is already known, it won't try.
//解析注解
MapperAnnotationBuilder parser = new MapperAnnotationBuilder(config, type);
parser.parse();
loadCompleted = true;
} finally {
//如果加载有问题，移除
if (!loadCompleted) {
knownMappers.remove(type);
}
}
}
}
注解解析
public MapperAnnotationBuilder(Configuration configuration, Class<?> type) {
String resource = type.getName().replace('.', '/') + ".java (best guess)";
this.assistant = new MapperBuilderAssistant(configuration, resource);
this.configuration = configuration;
this.type = type;
//添加需要解析的注解
sqlAnnotationTypes.add(Select.class);
sqlAnnotationTypes.add(Insert.class);
sqlAnnotationTypes.add(Update.class);
sqlAnnotationTypes.add(Delete.class);
sqlProviderAnnotationTypes.add(SelectProvider.class);
sqlProviderAnnotationTypes.add(InsertProvider.class);
sqlProviderAnnotationTypes.add(UpdateProvider.class);
sqlProviderAnnotationTypes.add(DeleteProvider.class);
}
MapperAnnotationBuilder.parse
public void org.apache.ibatis.builder.annotation.MapperAnnotationBuilder.parse() {
String resource = type.toString();
//是否已经加载
if (!configuration.isResourceLoaded(resource)) {
//加载xml配置，加载的配置与当前mapper在同一路径下，mapper接口类型
//点替换成正斜杠，然后加上.xml后缀，具体的解析逻辑和第二小节的是一样的
loadXmlResource();
//记录资源被加载
configuration.addLoadedResource(resource);
//设置namespace
assistant.setCurrentNamespace(type.getName());
//解析缓存
parseCache();
//解析缓存引用
parseCacheRef();
//获取接口的所有方法
Method[] methods = type.getMethods();
for (Method method : methods) {
try {
// issue #237
//不解析桥方法
if (!method.isBridge()) {
//解析语句
parseStatement(method);
}
} catch (IncompleteElementException e) {
//添加未解析的方法
configuration.addIncompleteMethod(new MethodResolver(this, method));
}
}
}
//解析尚解析的方法
parsePendingMethods();
}
- 解析缓存
private void org.apache.ibatis.builder.annotation.MapperAnnotationBuilder.parseCache() {
//获取@CacheNamespace注解
CacheNamespace cacheDomain = type.getAnnotation(CacheNamespace.class);
if (cacheDomain != null) {
//缓存大小
Integer size = cacheDomain.size() == 0 ? null : cacheDomain.size();
//刷新时间
Long flushInterval = cacheDomain.flushInterval() == 0 ? null : cacheDomain.flushInterval();
//这部分逻辑和解析xml时是一样的。
assistant.useNewCache(cacheDomain.implementation(),
cacheDomain.eviction(), flushInterval, size, cacheDomain.readWrite(), cacheDomain.blocking(), null);
}
}
- 解析缓存引用
private void parseCacheRef() {
//获取@CacheNamespaceRef注解
CacheNamespaceRef cacheDomainRef = type.getAnnotation(CacheNamespaceRef.class);
if (cacheDomainRef != null) {
//和解析xml是一样的
assistant.useCacheRef(cacheDomainRef.value().getName());
}
}
- 解析statement
void parseStatement(Method method) {
//解析参数，除了RowBounds和ResultHandler外，如果超过一个参数，那么参数类型
//定义为ParamMap，这是一个继承了HashMap的类
Class<?> parameterTypeClass = getParameterType(method);
//获取xml脚本驱动解析器
LanguageDriver languageDriver = getLanguageDriver(method);
//解析@select,@update,@delete注解，创建SqlSource
SqlSource sqlSource = getSqlSourceFromAnnotations(method, parameterTypeClass, languageDriver);
if (sqlSource != null) {
//解析@Options注解
Options options = method.getAnnotation(Options.class);
//接口名+方法名
final String mappedStatementId = type.getName() + "." + method.getName();
Integer fetchSize = null;
Integer timeout = null;
StatementType statementType = StatementType.PREPARED;
ResultSetType resultSetType = ResultSetType.FORWARD_ONLY;
//解析sql命令类型，通过使用的注解来判断，如@Select，那就是select，或者通过@SelectProvider等等
SqlCommandType sqlCommandType = getSqlCommandType(method);
boolean isSelect = sqlCommandType == SqlCommandType.SELECT;
boolean flushCache = !isSelect;
boolean useCache = isSelect;
KeyGenerator keyGenerator;
String keyProperty = "id";
String keyColumn = null;
if (SqlCommandType.INSERT.equals(sqlCommandType) || SqlCommandType.UPDATE.equals(sqlCommandType)) {
// first check for SelectKey annotation - that overrides everything else
//解析@SelectKey注解
SelectKey selectKey = method.getAnnotation(SelectKey.class);
if (selectKey != null) {
//创建获取主键的MappedStatement并创建SelectKeyGenerator，除了从注解中获取信息之外，其他的操作和解析xml配置是一样的
keyGenerator = handleSelectKeyAnnotation(selectKey, mappedStatementId, getParameterType(method), languageDriver);
keyProperty = selectKey.keyProperty();
} else if (options == null) {
keyGenerator = configuration.isUseGeneratedKeys() ? new Jdbc3KeyGenerator() : new NoKeyGenerator();
} else {
//从@Options注解上获取主键属性名，列名，构建Jdbc3KeyGenerator主键生成器
keyGenerator = options.useGeneratedKeys() ? new Jdbc3KeyGenerator() : new NoKeyGenerator();
keyProperty = options.keyProperty();
keyColumn = options.keyColumn();
}
} else {
keyGenerator = new NoKeyGenerator();
}
if (options != null) {
if (FlushCachePolicy.TRUE.equals(options.flushCache())) {
flushCache = true;
} else if (FlushCachePolicy.FALSE.equals(options.flushCache())) {
flushCache = false;
}
useCache = options.useCache();
fetchSize = options.fetchSize() > -1 || options.fetchSize() == Integer.MIN_VALUE ? options.fetchSize() : null; //issue #348
timeout = options.timeout() > -1 ? options.timeout() : null;
statementType = options.statementType();
resultSetType = options.resultSetType();
}
String resultMapId = null;
ResultMap resultMapAnnotation = method.getAnnotation(ResultMap.class);
if (resultMapAnnotation != null) {
String[] resultMaps = resultMapAnnotation.value();
StringBuilder sb = new StringBuilder();
for (String resultMap : resultMaps) {
if (sb.length() > 0) {
sb.append(",");
}
sb.append(resultMap);
}
resultMapId = sb.toString();
} else if (isSelect) {
resultMapId = parseResultMap(method);
}
//这里和解析xml的方式是一样的
assistant.addMappedStatement(
mappedStatementId,
sqlSource,
statementType,
sqlCommandType,
fetchSize,
timeout,
// ParameterMapID
null,
parameterTypeClass,
resultMapId,
getReturnType(method),
resultSetType,
flushCache,
useCache,
// TODO gcode issue #577
false,
keyGenerator,
keyProperty,
keyColumn,
// DatabaseID
null,
languageDriver,
// ResultSets
options != null ? nullOrEmpty(options.resultSets()) : null);
}
}
a. 解析参数
private Class<?> getParameterType(Method method) {
Class<?> parameterType = null;
Class<?>[] parameterTypes = method.getParameterTypes();
for (int i = 0; i < parameterTypes.length; i++) {
if (!RowBounds.class.isAssignableFrom(parameterTypes[i]) && !ResultHandler.class.isAssignableFrom(parameterTypes[i])) {
if (parameterType == null) {
parameterType = parameterTypes[i];
} else {
// issue #135
//除了RowBounds和ResultHandler外，如果超过一个参数，那么参数类型
//定义为ParamMap，这是一个继承了HashMap的类
parameterType = ParamMap.class;
}
}
}
return parameterType;
}
b. getSqlSourceFromAnnotations
private SqlSource org.apache.ibatis.builder.annotation.MapperAnnotationBuilder.getSqlSourceFromAnnotations(Method method, Class<?> parameterType, LanguageDriver languageDriver) {
try {
//获取@Select，@Update，@Delete，@Insert注解中其中一个，通过循环筛选
Class<? extends Annotation> sqlAnnotationType = getSqlAnnotationType(method);
//获取@SelectProvider，@InsertProvider，@UpdateProvider，@DeleteProvider
Class<? extends Annotation> sqlProviderAnnotationType = getSqlProviderAnnotationType(method);
if (sqlAnnotationType != null) {
if (sqlProviderAnnotationType != null) {
//不能同时存在
throw new BindingException("You cannot supply both a static SQL and SqlProvider to method named " + method.getName());
}
//获取对应注解
Annotation sqlAnnotation = method.getAnnotation(sqlAnnotationType);
//获取sql语句
final String[] strings = (String[]) sqlAnnotation.getClass().getMethod("value").invoke(sqlAnnotation);
//构建sqlSource
return buildSqlSourceFromStrings(strings, parameterType, languageDriver);
} else if (sqlProviderAnnotationType != null) {
//解析提供者上的sql和获取提供者
Annotation sqlProviderAnnotation = method.getAnnotation(sqlProviderAnnotationType);
return new ProviderSqlSource(assistant.getConfiguration(), sqlProviderAnnotation);
}
return null;
} catch (Exception e) {
throw new BuilderException("Could not find value method on SQL annotation. Cause: " + e, e);
}
}
c. buildSqlSourceFromStrings
private SqlSource buildSqlSourceFromStrings(String[] strings, Class<?> parameterTypeClass, LanguageDriver languageDriver) {
final StringBuilder sql = new StringBuilder();
//将片段连接起来
for (String fragment : strings) {
sql.append(fragment);
sql.append(" ");
}
//使用脚本解析驱动解析
//(*1*)
return languageDriver.createSqlSource(configuration, sql.toString().trim(), parameterTypeClass);
}
//(*1*)
public SqlSource createSqlSource(Configuration configuration, String script, Class<?> parameterType) {
// issue #3
//如果是以<script>开头，那么通过xml的方式解析
if (script.startsWith("<script>")) {
XPathParser parser = new XPathParser(script, false, configuration.getVariables(), new XMLMapperEntityResolver());
//这里面的解析方法就和解析解析xml是一样的了
return createSqlSource(configuration, parser.evalNode("/script"), parameterType);
} else {
// issue #127
//如果不是脚本，那么直接创建textSqlNode
script = PropertyParser.parse(script, configuration.getVariables());
TextSqlNode textSqlNode = new TextSqlNode(script);
if (textSqlNode.isDynamic()) {
return new DynamicSqlSource(configuration, textSqlNode);
} else {
return new RawSqlSource(configuration, script, parameterType);
}
}
}
d. ProviderSqlSource
public ProviderSqlSource(Configuration config, Object provider) {
String providerMethodName = null;
try {
this.sqlSourceParser = new SqlSourceBuilder(config);
//提供者的type类型
this.providerType = (Class<?>) provider.getClass().getMethod("type").invoke(provider);
//获取提供者方法
providerMethodName = (String) provider.getClass().getMethod("method").invoke(provider);
for (Method m : this.providerType.getMethods()) {
if (providerMethodName.equals(m.getName())) {
if (m.getReturnType() == String.class) {
//如果找到多个提供者方法，抛出错误
if (providerMethod != null){
throw new BuilderException("Error creating SqlSource for SqlProvider. Method '"
+ providerMethodName + "' is found multiple in SqlProvider '" + this.providerType.getName()
+ "'. Sql provider method can not overload.");
}
//设置提供者方法
this.providerMethod = m;
//解析@Param或者是以param1后去参数名列表
this.providerMethodArgumentNames = extractProviderMethodArgumentNames(m);
}
}
}
} catch (BuilderException e) {
throw e;
} catch (Exception e) {
throw new BuilderException("Error creating SqlSource for SqlProvider. Cause: " + e, e);
}
if (this.providerMethod == null) {
throw new BuilderException("Error creating SqlSource for SqlProvider. Method '"
+ providerMethodName + "' not found in SqlProvider '" + this.providerType.getName() + "'.");
}
}
好了，不管是配置的方式，还是注解的方式，改准备都已经准备好了，可以迎接请求了。
