java脚本注释格式（java的三种注释类型）

mybatis动态sql

mybatis，在带注解的映射器接口类中使用动态sql，可使用script元素，即：<script></script>。

案例代码

model

package com.what21.mybatis.model;

import lombok.data;

@data
public class employee {

    // id
    private integer id;
    // 名称
    private string name;
    // 邮箱
    private string email;
    // 性别
    private string gender;
    // 年龄
    private integer age;

}

mapper<映射器接口>

package com.what21.mybatis.demo03.mapper;

import com.what21.mybatis.model.employee;
import org.apache.ibatis.annotations.*;

import java.util.list;

public interface employeemapper {

    @select(value = "select * from `employee` where id = #{id}")
    @resulttype(employee.class)
    public employee findemployeebyid(integer id);

    @update(value = "<script>" +
            "update `employee` " +
            "   <set>" +
            "       <if test='name != null'>" +
            "           `name`=#{name}," +
            "       </if>" +
            "       <if test='email != null'>" +
            "            `email`=#{email}," +
            "       </if>" +
            "       <if test='gender != null'>" +
            "             `gender`=#{gender}," +
            "       </if>" +
            "       <if test='age != null'>" +
            "            `age`=#{age}  " +
            "       </if>" +
            "   </set>" +
            "where id = #{id}" +
            "</script>")
    public int updateemployee(employee employee);

    @delete(value = "<script>" +
            "   delete from `employee` where id in" +
            "       <foreach collection='idlist' item='id' open='(' separator=',' close=')'>" +
            "           #{id}" +
            "       </foreach>" +
            "</script>")
    public int deleteemployeebyids(@param("idlist") list<integer> idlist);

}

配置文件：

<?xml version="1.0" encoding="utf-8" ?>
<!doctype configuration
        public "-//mybatis.org//dtd config 3.0//en"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>

    <settings>
        <!--建议显示的指定需要配置的值，防止版本更新带来的问题-->
        <!--开启驼峰命名规则-->
        <setting name="mapunderscoretocamelcase" value="true"/>
    </settings>

    <typealiases>
        <typealias type="com.what21.mybatis.model.employee" alias="employee"/>
    </typealiases>

    <plugins>
        <plugin interceptor="com.github.pagehelper.pageinterceptor">
            <!--默认值为 false，当该参数设置为 true 时，如果 pagesize=0 或者 rowbounds.limit = 0 就会查询出全部的结果-->
            <!--如果某些查询数据量非常大，不应该允许查出所有数据-->
            <property name="pagesizezero" value="true"/>
        </plugin>
    </plugins>

    <environments default="development">
        <environment id="development">
            <transactionmanager type="jdbc"/>
            <datasource type="pooled">
                <property name="driver" value="com.mysql.jdbc.driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/demo?characterencoding=utf8&usessl=false&servertimezone=utc&rewritebatchedstatements=true"/>
                <property name="username" value="root"/>
                <property name="password" value="root"/>
            </datasource>
        </environment>
    </environments>

    <mappers>
        <mapper class="com.what21.mybatis.demo03.mapper.employeemapper" />
    </mappers>

</configuration>

测试类<main方法测试>：

package com.what21.mybatis.demo03;

import com.what21.mybatis.demo03.mapper.employeemapper;
import com.what21.mybatis.model.employee;
import org.apache.ibatis.io.resources;
import org.apache.ibatis.session.sqlsession;
import org.apache.ibatis.session.sqlsessionfactory;
import org.apache.ibatis.session.sqlsessionfactorybuilder;

import java.io.ioexception;
import java.io.reader;
import java.util.arrays;
import java.util.list;

public class mybatisdemomain {

    /**
     * 创建sessionfactory
     *
     * @param mybatisconfig
     * @return
     */
    private static sqlsessionfactory getsessionfactory(string mybatisconfig) {
        sqlsessionfactory sessionfactory = null;
        try {
            reader reader = resources.getresourceasreader(mybatisconfig);
            sessionfactory = new sqlsessionfactorybuilder().build(reader);
        } catch (ioexception e) {
            e.printstacktrace();
        }
        return sessionfactory;
    }

    public static void main(string[] args) {
        string resource = "com/what21/mybatis/demo03/mybatisconfig.xml";
        // 从sessionfactory中获取sqlsession
        sqlsession sqlsession = getsessionfactory(resource).opensession();
        // mapper
        employeemapper employeemapper = sqlsession.getmapper(employeemapper.class);
        // select操作
        employee findemployee = employeemapper.findemployeebyid(2);
        system.out.println(findemployee);
        findemployee.setname("学习测试demo");
        findemployee.setemail("[e-mail]");
        findemployee.setage(34);
        findemployee.setgender("1");
        int updateoperate = employeemapper.updateemployee(findemployee);
        system.out.println("update操作结果：" + updateoperate);
        list<integer> idslist = arrays.aslist(findemployee.getid());
        // delete操作
        int deleteoperate = employeemapper.deleteemployeebyids(idslist);
        // sql正确，没有删除任何一条数据，返回结果为：0
        system.out.println("delete操作结果：" + deleteoperate);
        // 提交
        //sqlsession.commit();
    }

}