• mybatis generator协助ssm开发心得总结


    一.配置

    mybatis generator用于自动生成相关表所对应的java文件,包括:javabean,dao接口,映射文件,如下所示:

     1 <?xml version="1.0" encoding="UTF-8"?>
     2 <!DOCTYPE generatorConfiguration
     3   PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
     4   "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">
     5 
     6 <generatorConfiguration>
     7 
     8   <context id="DB2Tables" targetRuntime="MyBatis3">
     9    <!-- 不生成注释 -->
    10    <commentGenerator>
    11       <property name="suppressAllComments" value="true" />
    12    </commentGenerator>
    13    <!-- 配置数据库连接信息 -->
    14     <jdbcConnection 
    15        driverClass="com.mysql.jdbc.Driver"
    16         connectionURL="jdbc:mysql://localhost:3306/******"
    17         userId="******"
    18         password="******">
    19     </jdbcConnection>
    20 
    21     <javaTypeResolver >
    22       <property name="forceBigDecimals" value="false" />
    23     </javaTypeResolver>
    24 
    25    <!-- 指定javabean生成的位置 -->
    26     <javaModelGenerator 
    27        targetPackage="com.cnblogs.xie.bean"
    28        targetProject=".srcmainjava">
    29       <property name="enableSubPackages" value="true" />
    30       <property name="trimStrings" value="true" />
    31     </javaModelGenerator>
    32 
    33    <!-- 指定sql映射文件生成的位置 -->
    34     <sqlMapGenerator 
    35        targetPackage="mapper"  
    36        targetProject=".srcmain
    esources">
    37       <property name="enableSubPackages" value="true" />
    38     </sqlMapGenerator>
    39 
    40    <!-- 指定dao接口生成的位置,mapper接口 -->
    41     <javaClientGenerator type="XMLMAPPER" 
    42        targetPackage="com.cnblogs.xie.dao"
    43        targetProject=".srcmainjava">
    44       <property name="enableSubPackages" value="true" />
    45     </javaClientGenerator>
    46 
    47    <!-- 指定每个表的生成策略 -->
    48     <table tableName="students" domainObjectName="Student"/>
    49   </context>
    50 </generatorConfiguration>

    其中tableName为表名,domainObjectName为javabean类名。

    二:使用

    1.试例:

    可以通过Service类调用其中方法,如下:

    public List<Loophole> getAll(){
        StudentExample example = new StudentExample();
        List<Student> list = studentMapper.selectByExample(example);
        return list;
    }

     以上代码作用为查询students表中的所有信息,与以下sql作用相同:

    select * from students;

    2.XXXExample类:

    如上例中的StudentExample类,它实例化的对象example负责对sql添加各种限制条件

    (1)example.isDistinct();

    select distinct * from students;

    (2)example.setOrderByClause("stu_id desc");

    select * from student order by stu_id desc;

    3.sql中的where子句:

    sql中的where子句又该如何添加呢?如下所示:

     StudentExample example = new example();
     StudentExample.Criteria criteria = studentExample.createCriteria();
     criteria.andStuAgeEqualTo(20);
     List<Student> students = studnetMapper.selectByExample(example);

     它的作用等同于:

    select * from students where stu_age = 20

     criteria还有很多方法,如下:

    andXXXEqualTo(xx)
          Between(xx,xx)
          In(List<xx>)
          GreaterThan(xx)
          LessThan(xx)
          Like(xx)
          IsNull()
          IsNotNull()
    ......

     4.sql中的or

    StudentExample example = new example();
     example.or().andStuIdEqualTo(xx)
     example.or().andStuAgeBetween(aa,bb);
     List<Student> students = studnetMapper.selectByExample(example);

    它的作用等同于:

    select * from student where stu_id = xx or stu_age between aa and bb
  • 相关阅读:
    open-falcon实现邮件报警
    open-falcon监控Flume
    Ubuntu下安装open-falcon-v0.2.1
    Python学习笔记——发邮件
    Flume的监控参数
    Ubuntu下安装Kafka Manager
    Ubuntu系统监控indicator-sysmonitor
    kafka性能测试
    Ubuntu下安装sbt
    Ubuntu安装shadow$ocks-libev
  • 原文地址:https://www.cnblogs.com/xiehuazhen/p/9483343.html
Copyright © 2020-2023  润新知