Mybatis generator生成工具简单介绍

Mybatis generator生成工具简单介绍

Mybatis generator

　　 其主要的功能就是方便，快捷的创建好Dao，entry，xml 加快了开发速度，使用方面根据其提供的规则配置好就OK

　　这里还有一个重要的开发场景，开发过程中，对数据库的操作肯定很多，比如新增字段什么的，你只要将原先自动生成的一套代码删除，重新再生成一份，这就完美解决了，但是这样做的前提是，你必须对生成后的代码不改动，只是使用。不需要想手动开发写代码那样到处改代码，还担心改漏地方。

　　其实这个的实现方式也是五花八门的，写一种比较常见的

---

 主要流程

　　第一步：添加依赖

　　主要是jdbc和generator

    org.mybatis.generator
    mybatis-generator-core
    1.3.6




    mysql
    mysql-connector-java
    5.1.38

---

　　　第二步：配置 generatorConfig.xml 

　　　　这个文件主要是对  从哪来，到哪去的描述，还有一些特殊要求的配置

　

---

 

　　　　第三步：主要看你个人的需求，对注释，分页啥的有啥要求不，可以重写几个方法对其进行改造

　　　　　　主要举几个例子  

　　　　对注释的修改 NewbatisGenerator 

public class NewbatisGenerator extends DefaultCommentGenerator {
    private Properties properties;
    private Properties systemPro;
    private boolean suppressDate;
    private boolean suppressAllComments;
    private String currentDateStr;

    public NewbatisGenerator() {
        super();
        properties = new Properties();
        systemPro = System.getProperties();
        suppressDate = false;
        suppressAllComments = false;
        currentDateStr = (new SimpleDateFormat("yyyy-MM-dd")).format(new Date());
    }

    /**
     * 对类的注解
     * @param topLevelClass
     * @param introspectedTable
     */
    @Override
    public void addModelClassComment(TopLevelClass topLevelClass, IntrospectedTable introspectedTable) {
        topLevelClass.addJavaDocLine("/**");
        topLevelClass.addJavaDocLine(" * 这是MyBatis Generator自动生成的Model Class.");

        StringBuilder sb = new StringBuilder();
        sb.append(" * 对应的数据表是 : ");
        sb.append(introspectedTable.getFullyQualifiedTable());
        topLevelClass.addJavaDocLine(sb.toString());

        String tableRemarks = introspectedTable.getRemarks();
        if (!StringUtils.isEmpty(tableRemarks)) {
            sb.setLength(0);
            sb.append(" * 数据表注释 : ");
            sb.append(tableRemarks);
            topLevelClass.addJavaDocLine(sb.toString());
        }

        sb.setLength(0);
        sb.append(" * @author ");
        sb.append(systemPro.getProperty("user.name"));
        topLevelClass.addJavaDocLine(sb.toString());

        String curDateString = (new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")).format(new Date());
        sb.setLength(0);
        sb.append(" * @date ");
        sb.append(curDateString);
        topLevelClass.addJavaDocLine(sb.toString());

        topLevelClass.addJavaDocLine(" */");
    }

    /**
     * 生成的实体增加字段的中文注释
     */
    public void addFieldComment(Field field, IntrospectedTable introspectedTable,
                                IntrospectedColumn introspectedColumn) {
        if (suppressAllComments) {
            return;
        }
        StringBuilder sb = new StringBuilder();
        field.addJavaDocLine("/**");
        sb.append(" * ");
        sb.append(introspectedColumn.getRemarks());
        field.addJavaDocLine(sb.toString().replace("\n", " "));
        field.addJavaDocLine(" */");
    }

}

　　对分页的添加  MysqlPaginationPlugin  自动生成带分页插件

public class MysqlPaginationPlugin extends PluginAdapter {
    public MysqlPaginationPlugin() {}

    public boolean modelExampleClassGenerated(TopLevelClass topLevelClass,
            IntrospectedTable introspectedTable) {
        this.addLimit(topLevelClass, introspectedTable, "limitStart");
        this.addLimit(topLevelClass, introspectedTable, "limitSize");
        return super.modelExampleClassGenerated(topLevelClass, introspectedTable);
    }

    public boolean sqlMapSelectByExampleWithoutBLOBsElementGenerated(XmlElement element,
            IntrospectedTable introspectedTable) {
        XmlElement isNotNullElement = new XmlElement("if");
        isNotNullElement
                .addAttribute(new Attribute("test", "limitStart != null and limitSize >= 0"));
        isNotNullElement.addElement(new TextElement("limit #{limitStart} , #{limitSize}"));
        element.addElement(isNotNullElement);
        return super.sqlMapSelectByExampleWithoutBLOBsElementGenerated(element, introspectedTable);
    }

    public boolean sqlMapSelectByExampleWithBLOBsElementGenerated(XmlElement element,
            IntrospectedTable introspectedTable) {
        XmlElement isNotNullElement = new XmlElement("if");
        isNotNullElement
                .addAttribute(new Attribute("test", "limitStart != null and limitSize >= 0"));
        isNotNullElement.addElement(new TextElement("limit #{limitStart} , #{limitSize}"));
        element.addElement(isNotNullElement);
        return super.sqlMapSelectByExampleWithBLOBsElementGenerated(element, introspectedTable);
    }

    private void addLimit(TopLevelClass topLevelClass, IntrospectedTable introspectedTable,
            String name) {
        CommentGenerator commentGenerator = this.context.getCommentGenerator();
        Field field = new Field();
        field.setVisibility(JavaVisibility.PROTECTED);
        field.setType(PrimitiveTypeWrapper.getIntegerInstance());
        field.setName(name);
        commentGenerator.addFieldComment(field, introspectedTable);
        topLevelClass.addField(field);
        char c = name.charAt(0);
        String camel = Character.toUpperCase(c) + name.substring(1);
        Method method = new Method();
        method.setVisibility(JavaVisibility.PUBLIC);
        method.setName("set" + camel);
        method.addParameter(new Parameter(PrimitiveTypeWrapper.getIntegerInstance(), name));
        StringBuilder sb = new StringBuilder();
        sb.append("this.");
        sb.append(name);
        sb.append(" = ");
        sb.append(name);
        sb.append(";");
        method.addBodyLine(sb.toString());
        commentGenerator.addGeneralMethodComment(method, introspectedTable);
        topLevelClass.addMethod(method);
        Method getterMethod = AbstractJavaGenerator.getGetter(field);
        commentGenerator.addGeneralMethodComment(getterMethod, introspectedTable);
        topLevelClass.addMethod(getterMethod);
    }

    public boolean validate(List warnings) {
        return true;
    }



    /**
     * 生成mapper.xml,文件内容会被清空再写入
     * */
    @Override
    public boolean sqlMapGenerated(GeneratedXmlFile sqlMap, IntrospectedTable introspectedTable) {
        sqlMap.setMergeable(false);
        return super.sqlMapGenerated(sqlMap, introspectedTable);
    }

}

　　最后一步：运行生成

　　这些官网都是有的

public class Generator {

    public static void main(String[] args) throws Exception{
        List warnings = new ArrayList();
        boolean overwrite = true;
        File configFile = new File("generatorConfig.xml");
        ConfigurationParser cp = new ConfigurationParser(warnings);
        Configuration config = cp.parseConfiguration(configFile);
        DefaultShellCallback callback = new DefaultShellCallback(overwrite);
        MyBatisGenerator myBatisGenerator = new MyBatisGenerator(config, callback, warnings);
        myBatisGenerator.generate(null);

    }
}

　　这个比较简单明了，个性化也不错，值得推荐

　　转载请注明出处：https://www.cnblogs.com/zhouguanglin/p/11239583.html