映射文件内的增删查改
准备工作
public class User {private String name;private String gender;private int age;private String address;private String email;private String qq;public String getName() {return name;}public void setName(String name) {this.name = name;}public String getGender() {return gender;}public void setGender(String gender) {this.gender = gender;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}public String getAddress() {return address;}public void setAddress(String address) {this.address = address;}public String getEmail() {return email;}public void setEmail(String email) {this.email = email;}public String getQq() {return qq;}public void setQq(String qq) {this.qq = qq;}
}<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configurationPUBLIC "-//mybatis.org//DTD Config 3.0//EN""http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration><environments default="development"><environment id="development"><transactionManager type="JDBC"></transactionManager><dataSource type="POOLED"><property name="driver" value="com.mysql.jdbc.Driver"/><property name="url" value="jdbc:mysql://localhost:3306/test?useSSL=false"/><property name="username" value="root"/><property name="password" value="123456"/></dataSource></environment></environments>
</configuration>public class Main {public static void main(String[] args) throws IOException {InputStream resourceAsStream = Resources.getResourceAsStream("mybatis.xml");SqlSession sqlSession = new SqlSessionFactoryBuilder().build(resourceAsStream).openSession();}
}后续只需在接口内添加相关方法，编写mapper映射文件进行测试，后面仅展示mapper映射文件。
新增数据
插入数据的方法sqlSession.insert("mapper映射文件内insert标签的id","传入的参数")，并且例如增删改的方法需要调用commit方法进行提交。
编写sql语句时，如果输入的参数为java对象类型，#{}表示接收java对象的属性名
<insert id="add" parameterType="com.cc.UserMapper" >
insert into tb_userinfo (name,gender,age,address,email,qq) values (#{name},#{gender},#{age},#{address},#{email},#{qq});
</insert>这里将user对象作为参数传入。
InputStream resourceAsStream = Resources.getResourceAsStream("mybatis.xml");SqlSession sqlSession = new SqlSessionFactoryBuilder().build(resourceAsStream).openSession();//插入数据User user = new User("张四丰","女",25,"宁夏","1212@qq.com","987654");sqlSession.insert("add",user);sqlSession.commit();删除数据
根据姓名删除数据：调用sqlSession.delete方法，同时传入一个字符串。
sqlSession.delete("delete","张大2");
<delete id="delete" parameterType="String">delete from tb_userinfo where name = #{na}</delete>修改数据
当要传入多个参数时，除了使用类将数据封装起来，还能使用map集合作为参数传入，注意map的key值要和#{}内的值一致。
<update id="update" parameterType="map">update tb_userinfo set gender=#{gender},address=#{address} where name=#{nam}</update> Map<String,String> map = new HashMap<>();map.put("gender","女");map.put("nam","李思思");map.put("address","四川");sqlSession.update("update",map);
查询数据
查询所有
<select id="seleteAll" resultType="com.cc.User">select * from tb_userinfo;</select> List<User> users = sqlSession.selectList("seleteAll");for(User u : users){System.out.print(u.getName());System.out.println(u.getAge());}条件查询
<select id="seleteByName" resultType="com.cc.User" parameterType="String">select * from tb_userinfo where name = #{name}</select> User user = sqlSession.selectOne("seleteByName", "李思思");System.out.println(user.getGender());System.out.println(user.getAddress());模糊查询
<select id="seleteLike" resultType="com.cc.User" parameterType="String">select * from tb_userinfo where name like #{name}</select> User o = sqlSession.selectOne("seleteLike", "%大%");System.out.println(o.getName());映射文件的相关补充
#{}与${}
#{}与${}都能够接收输入的参数，区别是#{}表示一个占位符号，${}表示一个拼接符号，这样会导致sql注入，因此不建议使用${}
parameterType和resultType
parameterType：指定输入参数类型，mybatis通过ognl从输入对象中获取参数值拼接在sql中。
resultType：指定输出结果类型，mybatis将sql查询结果的一行记录数据映射为resultType指定类型的对象。
