Mybatis-generator自动生成代码时提取自定义注释

深藏阁楼爱情的钟 2023-05-30 08:50 1阅读 0赞

在上篇文章中

[https://blog.csdn.net/yanyf2016/article/details/102972195][https_blog.csdn.net_yanyf2016_article_details_102972195]

生成的实体类没有数据库自己定义的注释，

根据网上找到的资料以及阅读Mybatis-generator源码，发现可以通过自定义注释生成器 CommentGenerator 接口的实现类来达到我们的目的。  
通过阅读源码可以看到，代码生成注释是通过DefaultCommentGenerator类实现的，这个类继承了CommentGenerator接口，因此我们可以自己创建一个类继承CommentGenerator接口，然后重写里面相关方法就可以了（可以复制DefaultCommentGenerator中的代码过来，然后修改我们需要改动的方法）。

下面介绍实现过程。  
1、自定义一个CommentGenerator接口的实现类，下面是我的自定义实现类代码

package com.generator;
    
    import java.text.SimpleDateFormat;
    import java.util.Date;
    import java.util.Properties;
    import java.util.Set;
    
    import org.mybatis.generator.api.CommentGenerator;
    import org.mybatis.generator.api.IntrospectedColumn;
    import org.mybatis.generator.api.IntrospectedTable;
    import org.mybatis.generator.api.dom.java.*;
    import org.mybatis.generator.api.dom.xml.XmlElement;
    import org.mybatis.generator.config.MergeConstants;
    import org.mybatis.generator.config.PropertyRegistry;
    
    /**
     * 自定义实现 注释生成器 CommentGenerator 接口
     * 
     */
    public class MyCommentGenerator implements CommentGenerator {
    
        private Properties properties;
        private Properties systemPro;
        private boolean suppressDate;
        private boolean suppressAllComments;
        private String nowTime;
    
        public MyCommentGenerator() {
            super();
            properties = new Properties();
            systemPro = System.getProperties();
            suppressDate = false;
            suppressAllComments = false;
            nowTime = (new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")).format(new Date());
        }
    
        public void addJavaFileComment(CompilationUnit compilationUnit) {
            if (suppressAllComments) {
                return;
            }
            return;
        }
    
        /**
         * Adds a suitable comment to warn users that the element was generated, and
         * when it was generated.
         */
        public void addComment(XmlElement xmlElement) {
            return;
        }
    
        public void addRootComment(XmlElement rootElement) {
            // add no document level comments by default
            return;
        }
    
        public void addGeneralMethodAnnotation(Method method, IntrospectedTable introspectedTable, Set<FullyQualifiedJavaType> set) {
    
        }
    
        public void addGeneralMethodAnnotation(Method method, IntrospectedTable introspectedTable, IntrospectedColumn introspectedColumn, Set<FullyQualifiedJavaType> set) {
    
        }
    
        public void addFieldAnnotation(Field field, IntrospectedTable introspectedTable, Set<FullyQualifiedJavaType> set) {
    
        }
    
        public void addFieldAnnotation(Field field, IntrospectedTable introspectedTable, IntrospectedColumn introspectedColumn, Set<FullyQualifiedJavaType> set) {
    
        }
    
        public void addClassAnnotation(InnerClass innerClass, IntrospectedTable introspectedTable, Set<FullyQualifiedJavaType> set) {
    
        }
    
        public void addConfigurationProperties(Properties properties) {
            this.properties.putAll(properties);
            suppressDate = isTrue(properties.getProperty(PropertyRegistry.COMMENT_GENERATOR_SUPPRESS_DATE));
            suppressAllComments = isTrue(properties.getProperty(PropertyRegistry.COMMENT_GENERATOR_SUPPRESS_ALL_COMMENTS));
        }
        
        /**
         * 判断传入参数是否为true
         * @param property
         * @return
         */
        private boolean isTrue(String property) {
            if("true".equals(property)){
                return true;
            }
            return false;
        }
    
        /**
         * This method adds the custom javadoc tag for. You may do nothing if you do
         * not wish to include the Javadoc tag - however, if you do not include the
         * Javadoc tag then the Java merge capability of the eclipse plugin will
         * break.
         * 
         * @param javaElement
         *            the java element
         */
        protected void addJavadocTag(JavaElement javaElement, boolean markAsDoNotDelete) {
            javaElement.addJavaDocLine(" *");
            StringBuilder sb = new StringBuilder();
            sb.append(" * ");
            sb.append(MergeConstants.NEW_ELEMENT_TAG);
            if (markAsDoNotDelete) {
                sb.append(" do_not_delete_during_merge");
            }
            String s = getDateString();
            if (s != null) {
                sb.append(' ');
                sb.append(s);
            }
            javaElement.addJavaDocLine(sb.toString());
        }
    
        /**
         * This method returns a formated date string to include in the Javadoc tag
         * and XML comments. You may return null if you do not want the date in
         * these documentation elements.
         * 
         * @return a string representing the current timestamp, or null
         */
        protected String getDateString() {
            String result = null;
            if (!suppressDate) {
                result = nowTime;
            }
            return result;
        }
    
        public void addClassComment(InnerClass innerClass, IntrospectedTable introspectedTable) {
            if (suppressAllComments) {
                return;
            }
            StringBuilder sb = new StringBuilder();
            innerClass.addJavaDocLine("/**");
            sb.append(" * ");
            sb.append(introspectedTable.getFullyQualifiedTable());
            sb.append(" ");
            sb.append(getDateString());
            innerClass.addJavaDocLine(sb.toString().replace("\n", " "));
            innerClass.addJavaDocLine(" */");
        }
    
        public void addEnumComment(InnerEnum innerEnum, IntrospectedTable introspectedTable) {
            if (suppressAllComments) {
                return;
            }
            StringBuilder sb = new StringBuilder();
            innerEnum.addJavaDocLine("/**");
            sb.append(" * ");
            sb.append(introspectedTable.getFullyQualifiedTable());
            innerEnum.addJavaDocLine(sb.toString().replace("\n", " "));
            innerEnum.addJavaDocLine(" */");
        }
        
        /**
         * 设置字段注释
         */
        public void addFieldComment(Field field, IntrospectedTable introspectedTable, IntrospectedColumn introspectedColumn) {
            if (suppressAllComments) {
                return;
            }
            StringBuilder sb = new StringBuilder();
            field.addJavaDocLine("/**");
            sb.append(" * ");
            sb.append(introspectedColumn.getRemarks() + " " + introspectedColumn.getActualColumnName());
            field.addJavaDocLine(sb.toString().replace("\n", " "));
            field.addJavaDocLine(" */");
        }
    
        public void addFieldComment(Field field, IntrospectedTable introspectedTable) {
            if (suppressAllComments) {
                return;
            }
            StringBuilder sb = new StringBuilder();
            field.addJavaDocLine("/**");
            sb.append(" * ");
            sb.append(introspectedTable.getFullyQualifiedTable());
            field.addJavaDocLine(sb.toString().replace("\n", " "));
            field.addJavaDocLine(" */");
        }
    
        public void addModelClassComment(TopLevelClass topLevelClass, IntrospectedTable introspectedTable) {
    
        }
    
        public void addGeneralMethodComment(Method method, IntrospectedTable introspectedTable) {
            if (suppressAllComments) {
                return;
            }
          method.addJavaDocLine("/**");
          addJavadocTag(method, false);
          method.addJavaDocLine(" */");
        }
        
        /**
         * 设置getter方法注释
         */
        public void addGetterComment(Method method, IntrospectedTable introspectedTable,
                IntrospectedColumn introspectedColumn) {
            if (suppressAllComments) {
                return;
            }
            method.addJavaDocLine("/**");
            StringBuilder sb = new StringBuilder();
            sb.append(" * ");
            sb.append(introspectedColumn.getRemarks());
            method.addJavaDocLine(sb.toString().replace("\n", " "));
            sb.setLength(0);
            
            //加入系统用户
            sb.append(" * @author ");
            sb.append(systemPro.getProperty("user.name"));
            method.addJavaDocLine(sb.toString().replace("\n", " "));
            sb.setLength(0);
            
            //是否加入时间戳
            if(suppressDate){
                sb.append(" * @date " + nowTime);
                method.addJavaDocLine(sb.toString().replace("\n", " "));
                sb.setLength(0);
            }
            
            sb.append(" * @return ");
            sb.append(introspectedColumn.getActualColumnName());
            sb.append(" ");
            sb.append(introspectedColumn.getRemarks());
            method.addJavaDocLine(sb.toString().replace("\n", " "));
            method.addJavaDocLine(" */");
        }
        
        /**
         * 设置setter方法注释
         */
        public void addSetterComment(Method method, IntrospectedTable introspectedTable,
                IntrospectedColumn introspectedColumn) {
            if (suppressAllComments) {
                return;
            }
            method.addJavaDocLine("/**");
            StringBuilder sb = new StringBuilder();
            sb.append(" * ");
            sb.append(introspectedColumn.getRemarks());
            method.addJavaDocLine(sb.toString().replace("\n", " "));
            sb.setLength(0);
            
            //加入系统用户
            sb.append(" * @author ");
            sb.append(systemPro.getProperty("user.name"));
            method.addJavaDocLine(sb.toString().replace("\n", " "));
            sb.setLength(0);
            
            //是否加入时间戳
            if(suppressDate){
                sb.append(" * @date " + nowTime);
                method.addJavaDocLine(sb.toString().replace("\n", " "));
                sb.setLength(0);
            }
            
            Parameter parm = method.getParameters().get(0);
            sb.append(" * @param ");
            sb.append(parm.getName());
            sb.append(" ");
            sb.append(introspectedColumn.getRemarks());
            method.addJavaDocLine(sb.toString().replace("\n", " "));
            method.addJavaDocLine(" */");
        }
    
        public void addClassComment(InnerClass innerClass, IntrospectedTable introspectedTable, boolean markAsDoNotDelete) {
            if (suppressAllComments) {
                return;
            }
            StringBuilder sb = new StringBuilder();
            innerClass.addJavaDocLine("/**");
            sb.append(" * ");
            sb.append(introspectedTable.getFullyQualifiedTable());
            innerClass.addJavaDocLine(sb.toString().replace("\n", " "));
            sb.setLength(0);
            sb.append(" * @author ");
            sb.append(systemPro.getProperty("user.name"));
            sb.append(" ");
            sb.append(nowTime);
            innerClass.addJavaDocLine(" */");
        }
        
    }

3.修改generatorConfig.xml，给commentGenerator元素设置type属性值为我们自定义类的全类名就可以了

最后，一般来说我们只需要实现实体类注释的方法就可以，如果觉得要实现CommentGenerator中所有的接口太麻烦的话，也可以让自定义实现类继承DefaultCommentGenerator类，然后重写与实体类属性、getter、setter注释相关的方法就可以了。

[https_blog.csdn.net_yanyf2016_article_details_102972195]: https://blog.csdn.net/yanyf2016/article/details/102972195