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;
@Service
public 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("----------------------------------");
    }
  }
}