史上最简单的MyBatis动态SQL入门示例代码

DROP DATABASE IF EXISTS `books`;CREATE DATABASE `books`;USE books;DROP TABLE IF EXISTS `book`;CREATE TABLE `book` ( `id` int(11) NOT NULL AUTO_INCREMENT, `name` varchar(128) DEFAULT NULL, `author` varchar(64) DEFAULT NULL, `press` varchar(64) DEFAULT NULL, `douban` FLOAT DEFAULT NULL, `isbn` varchar(13) DEFAULT NULL, PRIMARY KEY (`id`)) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8;INSERT INTO `book` (`name`,`author`,`press`,`douban`,`isbn`) VALUES('Java编程思想 第4版','（美）Bruce Eckel著','机械工业出版社',9.1,'9787111213826');INSERT INTO `book` (`name`,`author`,`press`,`douban`,`isbn`) VALUES('深入理解Java虚拟机 JVM高级特性与最佳实践','周志明著','机械工业出版社',8.8,'9787111421900');INSERT INTO `book` (`name`,`author`,`press`,`douban`,`isbn`) VALUES('疯狂Java讲义 第3版','李刚著','电子工业出版社',7.8,'9787121236693');INSERT INTO `book` (`name`,`author`,`press`,`douban`,`isbn`) VALUES('深入理解Java 7 核心技术与最佳实践','成富著','机械工业出版社',6.9,'9787111380399');

<select id="multipSearch" parameterType="map" resultType="net.sonng.entity.Book">  SELECT * FROM book   <where>    <if test="name!=null">      name LIKE #{name}    </if>    <if test="press!=null">      AND press LIKE #{press}    </if>    <if test="douban!=null">      AND douban>=#{douban}    </if>    <if test="isbn!=null">      AND isbn=#{isbn}    </if>  </where></select>

package net.sonng.service;import java.util.HashMap;import java.util.List;import java.util.Map;import javax.annotation.Resource;import net.sonng.dao.BookDao;import net.sonng.entity.Book;import org.springframework.stereotype.Service;@Servicepublic class TestService {  @Resource  private BookDao bookDao;  public List<Book> multipSearch(String name,String press,String douban,String isbn){    Map<String,String> map=new HashMap();    if (name!=null && !name.equals("")) {      map.put("name", "%"+name+"%");    }    if (press!=null && !press.equals("")) {      map.put("press","%"+press+"%");    }    if (douban!=null && !douban.equals("")){      map.put("douban", douban);    }    if (isbn!=null && !isbn.equals("")) {      map.put("isbn", isbn);    }    return bookDao.multipSearch(map);  }}

package net.sonng.test;import java.util.List;import net.sonng.controller.TestController;import net.sonng.entity.Book;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class Test {  public static void main(String[] args){    ApplicationContext ac=new ClassPathXmlApplicationContext("ac.xml");    TestController tc=ac.getBean("testController",TestController.class);//下面的4种查询语句，都可以一条动态SQL执行    //List<Book> books=tc.multipSearch("Java", "", "", "");        //查询到4条    //List<Book> books=tc.multipSearch("Java", "机械", "", "");      //3条    //List<Book> books=tc.multipSearch("Java", "机械", "8", "");      //2条    List<Book> books=tc.multipSearch("Java" ,"机械", "8", "9787111213826");//1条    for (Book book:books){      System.out.println(book.getId());      System.out.println(book.getName());      System.out.println(book.getIsbn());      System.out.println(book.getAuthor());      System.out.println(book.getPress());      System.out.println(book.getDouban());      System.out.println("----------------------------------");    }  }}