Mybatis（5）：使用sql映射文件，将返回结果封装为ResulMap

Mybatis（5）：使用sql映射文件，将返回结果封装为ResulMap

四部曲：

1.写接口  +  2.写映射sql  + 3.把mapper注册到mybatis的配置文件  + 4.写单元测试和运行

今天通过使用Mybatis框架·，将MySQL查询得到的数据封装为ResulMap，并映射到实体类User.java。这个过程是通过设置的resultMap属性为的id，从而调用了它。

下面是具体的代码：

（1）首先新建一个User.java文件，作为这次的实体类，注意一定要有setter方法（mybatis通过setter访问器进行读取）：

package com.smbms.entities;import java.util.Date;import java.util.List;public class User { private Integer id; private String userCode; private String userName; private String userPassword; private Integer gender; private Date birthday; private String phone; private String address ; private Integer userRole; private Integer createdBy; private Date creationDate; private Integer modifyBy; private Date modifyDate; public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getUserCode() { return userCode; } public void setUserCode(String userCode) { this.userCode = userCode; } public String getUserName() { return userName; } public void setUserName(String userName) { this.userName = userName; } public String getUserPassword() { return userPassword; } public void setUserPassword(String userPassword) { this.userPassword = userPassword; } public Integer getGender() { return gender; } public void setGender(Integer gender) { this.gender = gender; } public Date getBirthday() { return birthday; } public void setBirthday(Date birthday) { this.birthday = birthday; } public String getPhone() { return phone; } public void setPhone(String phone) { this.phone = phone; } public String getAddress() { return address; } public void setAddress(String address) { this.address = address; } public Integer getUserRole() { return userRole; } public void setUserRole(Integer userRole) { this.userRole = userRole; } public Integer getCreatedBy() { return createdBy; } public void setCreatedBy(Integer createdBy) { this.createdBy = createdBy; } public Date getCreationDate() { return creationDate; } public void setCreationDate(Date creationDate) { this.creationDate = creationDate; } public Integer getModifyBy() { return modifyBy; } public void setModifyBy(Integer modifyBy) { this.modifyBy = modifyBy; } public Date getModifyDate() { return modifyDate; } public void setModifyDate(Date modifyDate) { this.modifyDate = modifyDate; } public User(Integer id, String userCode, String userName, String userPassword, Integer gender, Date birthday, String phone, String address, Integer userRole, Integer createdBy, Date creationDate, Integer modifyBy, Date modifyDate) { super(); this.id = id; this.userCode = userCode; this.userName = userName; this.userPassword = userPassword; this.gender = gender; this.birthday = birthday; this.phone = phone; this.address = address; this.userRole = userRole; this.createdBy = createdBy; this.creationDate = creationDate; this.modifyBy = modifyBy; this.modifyDate = modifyDate; } public User() { super(); // TODO 自动生成的构造函数存根 } @Override public String toString() { return "User [id=" + id + ", userCode=" + userCode + ", userName=" + userName + ", userPassword=" + userPassword + ", gender=" + gender + ", birthday=" + birthday + ", phone=" + phone + ", address=" + address + ", userRole=" + userRole + ", createdBy=" + createdBy + ", creationDate=" + creationDate + ", modifyBy=" + modifyBy + ", modifyDate=" + modifyDate + "]"; } }

（2）然后，新建一个接口类 UserMapper.java，定义一个新的方法 public List getUserList(User user) ;：

package com.smbms.dao;import java.util.List;import java.util.Map;import org.apache.ibatis.annotations.Param;import com.smbms.entities.User;public interface UserMapper { public List getUserList(User user);public List getUserList(User user);

（3）然后，新建一个UserMapper.xml文件，用来编写sql映射语句：

【业务模型传递参数到sql执行查询操作：parameterType = "com.smbms.entities.User“；】

【数据库返回的结果到业务模型，调用了 resultMap：resultMap="userlist" 】

select u.*,r.rolename from smbms_user u ,smbms_role r where u.username like CONCAT('%',#{username},'%') and u.userRole = #{userRole} and u.userRole = r.id select u.*,r.rolename from smbms_user u ,smbms_role r where u.username like CONCAT('%',#{username},'%') and u.userRole = #{userRole} and u.userRole = r.id

（4）编写测试用例，导入JUnit4.jar后，可以新建测试用例UserTest.java：

package com.smbms.entities;import java.io.IOException;import java.io.InputStream;import java.text.ParseException;import java.text.SimpleDateFormat;import java.util.ArrayList;import java.util.Date;import java.util.HashMap;import java.util.List;import java.util.Map;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 org.junit.Test;import com.smbms.dao.ProviderMapper;import com.smbms.dao.UserMapper;public class UserTest { public SqlSession getSqlSession() throws IOException{ String resource = "mybatis-config.xml"; InputStream inputStream = Resources.getResourceAsStream(resource); SqlSessionFactory build = new SqlSessionFactoryBuilder().build(inputStream); SqlSession openSession = build.openSession(); return openSession; }

//使用resultMap完成查询结果的展现 @Test public void test06() throws IOException{ User user = new User(); user.setUserName("mmb"); user.setUserRole(110); SqlSession session = getSqlSession(); UserMapper mapper = session.getMapper(UserMapper.class); List userByUsername = mapper.getUserList(user); for(User user1:userByUsername){ System.out.println("+*+:" +user1.getUserRoleName()+user1.getPhone()+user1.getUserCode()+user1.getUserName()+user1.getUserRole()); } }

}

由此完成一个小Demo。

注意之处：

（1）ResulMap 具有两个元素：type 和 id ，type对应结果映射的实体类，id 是Map的唯一标识；

（2）result 是 ResulMap 下的标签元素，具有两个属性：property 和 column， column 对应于数据库的列名，property 对应于实体类定义的属性变量。

版权声明：本文内容由网络用户投稿，版权归原作者所有，本站不拥有其著作权，亦不承担相应法律责任。如果您发现本站中有涉嫌抄袭或描述失实的内容，请联系我们jiasou666@gmail.com 处理，核实后本网站将在24小时内删除侵权内容。