mybatis-plus 相关

这里有几个很全的教程:

https://www.cnblogs.com/okong/p/mybatis-plus-guide-one.html

mybtais-plus学习--BaseMapper提供的方法及SQL语句生成

1、实体继承 Model 如下

public class Test extends Model<Test> {

    // 静态属性会自动忽略
    private static final long serialVersionUID = 1L;

    /** 主键 */
    // 默认会找 id 为主键，特殊命名需要注解 @TableId
    private Long id;

    private String type;

    ...

    @Override
    protected Serializable pkVal() {
        return id;
    }

}

2、使用方法如下：

import java.io.InputStream;
import java.util.List;
import java.util.Map;

import org.apache.ibatis.jdbc.SQL;
import org.apache.ibatis.session.SqlSessionFactory;

import com.baomidou.mybatisplus.MybatisSessionFactoryBuilder;
import com.baomidou.mybatisplus.plugins.Page;
import com.baomidou.mybatisplus.test.mysql.TestMapper;
import com.baomidou.mybatisplus.test.mysql.entity.Test;
import com.baomidou.mybatisplus.toolkit.IdWorker;
import com.baomidou.mybatisplus.toolkit.TableInfoHelper;

/**
 * <p>
 * ActiveRecord 测试
 * </p>
 */
public class ActiveRecordTest {

    public static void main(String[] args) {
        // 加载配置文件
        InputStream in = TestMapper.class.getClassLoader().getResourceAsStream("mysql-config.xml");
        MybatisSessionFactoryBuilder mf = new MybatisSessionFactoryBuilder();
        SqlSessionFactory sqlSessionFactory = mf.build(in);
        TableInfoHelper.initSqlSessionFactory(sqlSessionFactory);
        sqlSessionFactory.openSession(false);
        // 保存一条记录
        Test t1 = new Test();
        t1.setType("test10");
        boolean rlt = t1.insert();
        print(" ar save=" + rlt + ", id=" + t1.getId());

        // 根据ID更新
        t1.setType("t1023");
        rlt = t1.updateById();
        print(" ar updateById:" + rlt);

        // 更新 SQL
        Test t11 = new Test();
        t11.setType("123");
        rlt = t11.update("id={0}", t1.getId());
        print("update sql=" + rlt);

        // 查询 SQL
        Test t10 = t1.selectOne("id={0}", t1.getId());
        print("selectOne=" + t10.getType());

        // 插入OR更新
        t1.setType("t1021");
        rlt = t1.insertOrUpdate();
        print(" ar saveOrUpdate:" + rlt);

        // 根据ID查询
        Test t2 = t1.selectById();
        print(" t2 = " + t2.toString());
        t2.setId(IdWorker.getId());
        t2.insert();

        // 查询所有
        List<Test> tl = t2.selectAll();
        for (Test t : tl) {
            print("selectAll=" + t.toString());
        }

        // 查询总记录数
        print(" count=" + t2.selectCount(null));

        // 翻页查询
        Page<Test> page = new Page<Test>(0, 10);
        page = t2.selectPage(page, null);
        print(page.toString());

        // 根据ID删除
        rlt = t2.deleteById();
        print("deleteById=" + rlt + ", id=" + t2.getId());

        // 执行 SQL 查询总数
        List<Map<String, Object>> ul = t2.sql().selectList(new SQL() {
            {
                SELECT("*");
                FROM("test");
                WHERE("type='t1021'");
            }
        }.toString());
        System.err.println("selectList SQL:");
        for (Map<String, Object> map : ul) {
            System.err.println(map);
        }

        // 根据ID查询
        Test t20 = t2.selectById();
        print("t2 删除后是否存在？" + (null != t20));

        // 删除 SQL
        rlt = t2.delete("type={0}", "t1021");
        System.err.println("delete sql=" + rlt);
    }

    /*
     * 慢点打印
     */
    private static void print(String text) {
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.err.println(text);
    }

}