mybatis generator插件系列--分页插件

1、首先定义分页插件

MysqlPagePlugin.java

package com.demo.mybatis.plugin;

import org.mybatis.generator.api.CommentGenerator;
import org.mybatis.generator.api.IntrospectedTable;
import org.mybatis.generator.api.PluginAdapter;
import org.mybatis.generator.api.dom.java.*;
import org.mybatis.generator.api.dom.xml.Attribute;
import org.mybatis.generator.api.dom.xml.TextElement;
import org.mybatis.generator.api.dom.xml.XmlElement;

import java.util.List;
/**
 * <pre>
 * add pagination using mysql limit.
 * This class is only used in ibator code generator.
 * </pre>
 */

/**
 * mysql 分页生成插件
 */

public class MysqlPagePlugin extends PluginAdapter {

    /**
     * 添加 分页 开始行数 和结束行数 属性
     */
    @Override
    public boolean modelExampleClassGenerated(TopLevelClass topLevelClass,
                                              IntrospectedTable introspectedTable) {
        // add field, getter, setter for limit clause

        addProperty(topLevelClass, introspectedTable, "limitStart", FullyQualifiedJavaType.getIntInstance());

        addProperty(topLevelClass, introspectedTable, "limitEnd", FullyQualifiedJavaType.getIntInstance());

        addProperty(topLevelClass, introspectedTable, "groupByClause", FullyQualifiedJavaType.getStringInstance());

        return super.modelExampleClassGenerated(topLevelClass, introspectedTable);
    }

    /**
     * 添加 映射 文件配置 limit 的配置
     */
    @Override
    public boolean sqlMapSelectByExampleWithoutBLOBsElementGenerated(
            XmlElement element, IntrospectedTable introspectedTable) {

//		XmlElement isParameterPresenteElemen = (XmlElement) element.getElements();
        //设置 if 判断 节点
        XmlElement limitElement = new XmlElement("if"); //$NON-NLS-1$

        //给 节点添加 条件运算符
        limitElement.addAttribute(new Attribute("test", "limitEnd > 0")); //$NON-NLS-1$ //$NON-NLS-2$
        //如果条件成立 就进行分页查询
        limitElement.addElement(new TextElement(
                "limit #{limitStart,jdbcType=INTEGER}  , #{limitEnd,jdbcType=INTEGER}"));
        //添加节点到 配置文件中
        element.addElement(limitElement);

        XmlElement groupbyElement = new XmlElement("if"); //$NON-NLS-1$

        //给 节点添加 条件运算符
        groupbyElement.addAttribute(new Attribute("test", "groupByClause != null")); //$NON-NLS-1$ //$NON-NLS-2$
        //如果条件成立 就进行分页查询
        groupbyElement.addElement(new TextElement(
                "group by ${groupByClause}"));
        //添加节点到 配置文件中
        element.addElement(groupbyElement);

        return super.sqlMapUpdateByExampleWithoutBLOBsElementGenerated(element, introspectedTable);

    }

    /**
     * 给对应的实体 实体添加 属性字段
     */
    private void addProperty(TopLevelClass topLevelClass,
                             IntrospectedTable introspectedTable, String name, FullyQualifiedJavaType fullyQualifiedJavaType) {
        CommentGenerator commentGenerator = context.getCommentGenerator();
        Field field = new Field();
        field.setVisibility(JavaVisibility.PROTECTED);
        field.setType(fullyQualifiedJavaType);
        field.setName(name);

//		field.setInitializationString("-1");

        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(fullyQualifiedJavaType, name));

        method.addBodyLine("this." + name + "=" + name + ";");
        commentGenerator.addGeneralMethodComment(method, introspectedTable);
        topLevelClass.addMethod(method);
        method = new Method();
        method.setVisibility(JavaVisibility.PUBLIC);
        method.setReturnType(fullyQualifiedJavaType);
        method.setName("get" + camel);
        method.addBodyLine("return " + name + ";");
        commentGenerator.addGeneralMethodComment(method, introspectedTable);
        topLevelClass.addMethod(method);
    }

    /**
     * This plugin is always valid - no properties are required
     */
    public boolean validate(List<String> warnings) {
        return true;
    }

//	public static void generate() {
//		String config = MysqlPagePlugin.class.getClassLoader().getResource("generatorConfig-w5Log.xml").getFile();
//		String[] arg = { "-configfile", config, "-overwrite" };
//		ShellRunner.main(arg);
//	}
//	public static void main(String[] args) {
//		generate();
//	}

}

2、然后为mybatisgenerator配置插件

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE generatorConfiguration PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN" "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">

<generatorConfiguration>
    <context id="context1">

        <!-- 使用自带序列化插件 -->
        <plugin type="org.mybatis.generator.plugins.SerializablePlugin"/>

        <!-- 使用自定义的插件 -->
        <plugin type="com.demo.mybatis.plugin.MysqlPagePlugin"/>

        <jdbcConnection driverClass="com.mysql.jdbc.Driver"
         connectionURL="jdbc:mysql://localhost:3306/test?useUnicode=true&amp;characterEncoding=UTF8"
         userId="root" password="123456">
        </jdbcConnection>

        <javaModelGenerator targetPackage="com.ilovey.biz.entity.base"
         targetProject="ilovey.biz/src/main/java"/>
        <sqlMapGenerator targetPackage="com.ilovey.biz.mapper.base"
         targetProject="ilovey.biz/src/main/resources"/>
        <javaClientGenerator targetPackage="com.ilovey.biz.mapper.base"
         targetProject="ilovey.biz/src/main/java" type="XMLMAPPER"/>

        <table tableName="us_user_info"  domainObjectName="UsUserInfo">
            <generatedKey column="id" sqlStatement="MySql" identity="true"/>
        </table>

    </context>
</generatorConfiguration>

3、使用示例

@Repository
public class UsUserInfoDao {

    @Autowired
    private UsUserInfoMapper usUserMapper;

    /**
     * 分页查询用户信息
     * @param kinCode   用户类型
     * @param page      分页参数（page为自定义的对象）
     * @return
     */
    public List<UsUserInfo> listUserInfo(String kinCode, Page page) {
        UsUserInfoExample example = new UsUserInfoExample();
        example.createCriteria().andKindCodeEqualTo(kinCode);

        //分页
        example.setLimitStart(page.limitStart());
        example.setLimitEnd(page.limitEnd());

        //排序
        example.setOrderByClause("create_time desc");

        //查询总数
        page.setTotalCount(usUserMapper.countByExample(example));

      return usUserMapper.selectByExample(example);
    }
}

本文所有代码及demo：https://gitee.com/chaocloud/generator-demo.git