关于 mybatis generator 插件，官方提供了一些参考的third-party-tools，但是在实际开发的项目中，遇到了一些相关的问题，以下是写相关记录（主要是配合 gradle 使用）。
1. LombokPlugin 插件
这个很多博客上都有，也就不再重复论了，贴一下 code
public class LombokPlugin extends PluginAdapter {
private final Set<Annotations> annotations;
/**
* LombokPlugin constructor
*/
public LombokPlugin() {
annotations = new LinkedHashSet<>(Annotations.values().length);
}
/**
* @param warnings list of warnings
* @return always true
*/
@Override
public boolean validate(List<String> warnings) {
return true;
}
/**
* Intercepts base record class generation
*
* @param topLevelClass the generated base record class
* @param introspectedTable The class containing information about the table as
* introspected from the database
* @return always true
*/
@Override
public boolean modelBaseRecordClassGenerated(TopLevelClass topLevelClass, IntrospectedTable introspectedTable) {
addAnnotations(topLevelClass);
return true;
}
/**
* Intercepts primary key class generation
*
* @param topLevelClass the generated primary key class
* @param introspectedTable The class containing information about the table as
* introspected from the database
* @return always true
*/
@Override
public boolean modelPrimaryKeyClassGenerated(TopLevelClass topLevelClass, IntrospectedTable introspectedTable) {
addAnnotations(topLevelClass);
return true;
}
/**
* Intercepts "record with blob" class generation
*
* @param topLevelClass the generated record with BLOBs class
* @param introspectedTable The class containing information about the table as
* introspected from the database
* @return always true
*/
@Override
public boolean modelRecordWithBLOBsClassGenerated(TopLevelClass topLevelClass,
IntrospectedTable introspectedTable) {
addAnnotations(topLevelClass);
return true;
}
/**
* Prevents all getters from being generated.
* See SimpleModelGenerator
*
* @param method the getter, or accessor, method generated for the specified
* column
* @param topLevelClass the partially implemented model class
* @param introspectedColumn The class containing information about the column related
* to this field as introspected from the database
* @param introspectedTable The class containing information about the table as
* introspected from the database
* @param modelClassType the type of class that the field is generated for
*/
@Override
public boolean modelGetterMethodGenerated(
Method method,
TopLevelClass topLevelClass,
IntrospectedColumn introspectedColumn,
IntrospectedTable introspectedTable,
ModelClassType modelClassType) {
return false;
}
/**
* Prevents all setters from being generated
* See SimpleModelGenerator
*
* @param method the setter, or mutator, method generated for the specified
* column
* @param topLevelClass the partially implemented model class
* @param introspectedColumn The class containing information about the column related
* to this field as introspected from the database
* @param introspectedTable The class containing information about the table as
* introspected from the database
* @param modelClassType the type of class that the field is generated for
* @return always false
*/
@Override
public boolean modelSetterMethodGenerated(
Method method,
TopLevelClass topLevelClass,
IntrospectedColumn introspectedColumn,
IntrospectedTable introspectedTable,
ModelClassType modelClassType) {
return false;
}
/**
* Adds the lombok annotations' imports and annotations to the class
*
* @param topLevelClass the partially implemented model class
*/
private void addAnnotations(TopLevelClass topLevelClass) {
for (Annotations annotation : annotations) {
topLevelClass.addImportedType(annotation.javaType);
topLevelClass.addAnnotation(annotation.asAnnotation());
}
}
@Override
public void setProperties(Properties properties) {
super.setProperties(properties);
//@Data,@Builder,@NoArgsConstructor,@AllArgsConstructor is default annotation
annotations.add(Annotations.DATA);
annotations.add(Annotations.BUILDER);
annotations.add(Annotations.NO_ARGS_CONSTRUCTOR);
annotations.add(Annotations.ALL_ARGS_CONSTRUCTOR);
for (String annotationName : properties.stringPropertyNames()) {
if (annotationName.contains(".")) {
// Not an annotation name
continue;
}
String value = properties.getProperty(annotationName);
if (!Boolean.parseBoolean(value)) {
// The annotation is disabled, skip it
continue;
}
Annotations annotation = Annotations.getValueOf(annotationName);
if (annotation == null) {
continue;
}
String optionsPrefix = annotationName + ".";
for (String propertyName : properties.stringPropertyNames()) {
if (!propertyName.startsWith(optionsPrefix)) {
// A property not related to this annotation
continue;
}
String propertyValue = properties.getProperty(propertyName);
annotation.appendOptions(propertyName, propertyValue);
annotations.add(annotation);
annotations.addAll(Annotations.getDependencies(annotation));
}
}
}
private enum Annotations {
DATA("data", "@Data", "lombok.Data"),
BUILDER("builder", "@Builder", "lombok.Builder"),
ALL_ARGS_CONSTRUCTOR("allArgsConstructor", "@AllArgsConstructor", "lombok.AllArgsConstructor"),
NO_ARGS_CONSTRUCTOR("noArgsConstructor", "@NoArgsConstructor", "lombok.NoArgsConstructor"),
ACCESSORS("accessors", "@Accessors", "lombok.experimental.Accessors"),
TO_STRING("toString", "@ToString", "lombok.ToString");
private final String paramName;
private final String name;
private final FullyQualifiedJavaType javaType;
private final List<String> options;
Annotations(String paramName, String name, String className) {
this.paramName = paramName;
this.name = name;
javaType = new FullyQualifiedJavaType(className);
options = new ArrayList<>();
}
private static Annotations getValueOf(String paramName) {
for (Annotations annotation : Annotations.values()) {
if (String.CASE_INSENSITIVE_ORDER.compare(paramName, annotation.paramName) == 0) {
return annotation;
}
}
return null;
}
private static Collection<Annotations> getDependencies(Annotations annotation) {
if (annotation == ALL_ARGS_CONSTRUCTOR) {
return Collections.singleton(NO_ARGS_CONSTRUCTOR);
} else {
return Collections.emptyList();
}
}
// A trivial quoting.
// Because Lombok annotation options type is almost String or boolean.
private static String quote(String value) {
if (Boolean.TRUE.toString().equals(value) || Boolean.FALSE.toString().equals(value)) {
return value;
}
// case of boolean, not passed as an array.
return value.replaceAll("[\\w]+", "\"$0\"");
}
private void appendOptions(String key, String value) {
String keyPart = key.substring(key.indexOf(".") + 1);
String valuePart = value.contains(",") ? String.format("{%s}", value) : value;
options.add(String.format("%s=%s", keyPart, quote(valuePart)));
}
private String asAnnotation() {
if (options.isEmpty()) {
return name;
}
StringBuilder sb = new StringBuilder();
sb.append(name);
sb.append("(");
boolean first = true;
for (String option : options) {
if (first) {
first = false;
} else {
sb.append(", ");
}
sb.append(option);
}
sb.append(")");
return sb.toString();
}
}
}
2. ServicePlugin 插件
主要是为了便于自动生成 Service 类
public class ServicePlugin extends PluginAdapter {
private String targetProject;
private String targetPackage;
@Override
public boolean validate(List<String> list) {
return true;
}
@Override
public void setProperties(Properties properties) {
super.setProperties(properties);
String targetProject = this.properties.getProperty("targetProject");
if (StringUtility.stringHasValue(targetProject)) {
this.targetProject = targetProject;
} else {
throw new RuntimeException("targetProject 属性不能为空！");
}
String targetPackage = this.properties.getProperty("targetPackage");
if (StringUtility.stringHasValue(targetPackage)) {
this.targetPackage = targetPackage;
} else {
throw new RuntimeException("targetPackage 属性不能为空！");
}
}
/**
* @param introspectedTable
* @return
*/
@Override
public List<GeneratedJavaFile> contextGenerateAdditionalJavaFiles(IntrospectedTable introspectedTable) {
FullyQualifiedJavaType entityType = new FullyQualifiedJavaType(introspectedTable.getBaseRecordType());
String domainObjectName = introspectedTable.getFullyQualifiedTable().getDomainObjectName();
String service = targetPackage + "." + domainObjectName + "Service";
TopLevelClass topLevelClass = new TopLevelClass(new FullyQualifiedJavaType(service));
topLevelClass.addImportedType(entityType);
topLevelClass.addImportedType(new FullyQualifiedJavaType(service));
topLevelClass.addImportedType(new FullyQualifiedJavaType("org.springframework.stereotype.Service"));
topLevelClass.addImportedType(new FullyQualifiedJavaType("org.springframework.beans.factory.annotation" +
".Autowired"));
topLevelClass.addImportedType(new FullyQualifiedJavaType("cn.mwee.service.base_framework.mysql.service" +
".BaseService"));
topLevelClass.addAnnotation("@Service(\"" + firstLetterLowerCase(domainObjectName + "Service") + "\")");
topLevelClass.setVisibility(JavaVisibility.PUBLIC);
topLevelClass.setSuperClass(new FullyQualifiedJavaType("BaseService<" + entityType.getShortName() + ">"));
setMapperField(introspectedTable, topLevelClass);
ElementUtil.addAuthorTag(topLevelClass);
return Arrays.asList(new GeneratedJavaFile(topLevelClass, targetProject, new DefaultJavaFormatter()));
}
/**
* @param introspectedTable
* @param clazz
*/
private void setMapperField(IntrospectedTable introspectedTable, TopLevelClass clazz) {
// 实体类的类名
String domainObjectName = introspectedTable.getFullyQualifiedTable().getDomainObjectName();
// Mapper类所在包的包名
String mapperPackage = introspectedTable.getContext().getJavaClientGeneratorConfiguration().getTargetPackage();
Field mapperField = new Field();
// 设置Field的注解
mapperField.addAnnotation("@Autowired");
mapperField.setVisibility(JavaVisibility.PRIVATE);
// 设置Field的类型
mapperField.setType(new FullyQualifiedJavaType(domainObjectName + "Mapper"));
// 设置Field的名称
mapperField.setName(firstLetterLowerCase(domainObjectName) + "Mapper");
// 将Field添加到对应的类中
clazz.addField(mapperField);
// 对应的类需要import Mapper类(使用全限定类名)
clazz.addImportedType(new FullyQualifiedJavaType(mapperPackage + "." + domainObjectName + "Mapper"));
}
private String firstLetterLowerCase(String name) {
char c = name.charAt(0);
if (c >= 'A' && c <= 'Z') {
String temp = String.valueOf(c);
return name.replaceFirst(temp, temp.toLowerCase());
}
return name;
}
}
3. 解决数据库 Unsigned 类型字段
使用官方 mybatis generator 1.3.7 版本自动生产的实体类映射，是不能区分 Unsigned 和 Signed mysql 8.x（针对 java 项目，很容易出现类型字段溢出），尤其实际项目中，接手老的项目，之前一些数据库字段的设置，留下来的一些“坑”；
- 官方方案：（github 上也有一些小伙伴提了相应的 issue，好像没有 fixed）
<columnOverride>元素覆盖指定的字段
缺点：在针对很多表的时候，都需要手动设置这些字段，而且很容易丢失（可能导致线上问题） - 解决方案：
通过 download 官方 mybatis generator 源码，发现是可以自动识别 Unsigned 和 Signed 字段属性的，故修改了源码，打包，重新编译，达到了想要的目的，不需要针对指定的字段每一个修改（在 github 上已经和官方作者沟通，接受了 issue，将于下一个版本 1.4.0 做增强），由于官方作者一直没发布 1.4.0，故公司内部打包如下 Jar 版本：mybatis-generator-maven-plugin-1.3.7.2.jar
4. 如何自动生成 jdk8 时间映射
之前是打算直接写插件直接自动生成，但是考虑到有些项目还是用的 jdk8 以前的时间，老的项目也不能强制要求 jdk8 时间版本，故下面 👇 只是展示如何处理.
在生成的实体类中加入下面处理
<columnOverride column="created_time" property="createdTime"
typeHandler="org.apache.ibatis.type.LocalDateTimeTypeHandler"
jdbcType="OTHER" javaType="java.time.LocalDateTime"/>
<columnOverride column="updated_time" property="updatedTime"
typeHandler="org.apache.ibatis.type.LocalDateTimeTypeHandler"
jdbcType="OTHER" javaType="java.time.LocalDateTime"/>
注：在 mybatis 使用 jdk8 时间时，需要注意的是，mybatis 3.5.1+和 druid 1.1.20 是不支持 jdk8 的时间戳的druid-jdk8，不过，现在已经修复了，等下一个版本估计就能解决了（当然，也可以切换到 HikariCP 数据源）
5. 集成 gradle 插件
市场上已经有很多 gradle 集成 mybatis generator，选择了其中一个比较好用的插件mybatis-generator-plugin（尊重原创作者），当然在公司内部处理，也针对这个插件做了相应的修改定制
6. 附录
针对上面 👆 的一些处理，生成的结构图如下：
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