mybatis使用foreach遍历list集合或者array数组方式 mybatis使用foreach遍历list集合或

一、准备工作 1.db.properties文件（记得修改自己的数据库和用户名、密码）

dataSource.driver=com.mysql.jdbc.DriverdataSource.url=jdbc:mysql://localhost:3306/mybatis?useUnicode=true&characterEncoding=utf8dataSource.username=blogdataSource.password=blog

2.主配置文件

3.创建User类和包装类UserVo
User.java

package com.mybatis_demo.domain; public class User { private Integer uid; private String uname; private Integer age; private String address; public Integer getUid() {return uid; } public void setUid(Integer uid) {this.uid = uid; } public String getUname() {return uname; } public void setUname(String uname) {this.uname = uname; } public Integer getAge() {return age; } public void setAge(Integer age) {this.age = age; } public String getAddress() {return address; } public void setAddress(String address) {this.address = address; } @Override public String toString() {return "User [uid=" + uid + ", uname=" + uname + ", age=" + age + ", address=" + address + "]"; }}

UserVo.java

package com.mybatis_demo.domain; import java.util.List; public class UserVo extends User { private Integer[] ids; private List idList; public Integer[] getIds() {return ids; } public void setIds(Integer[] ids) {this.ids = ids; } public List getIdList() {return idList; } public void setIdList(List idList) {this.idList = idList; } }

二、遍历数组和集合的映射文件和对应的接口 1.mapper映射文件

select * from t_user where uid in #{item} select * from t_user where uid in #{item} select * from t_user where uid in #{item} select * from t_user where uid in #{item}

2.mapper接口
UserMapper.interface

package com.mybatis_demo.mapper; import java.util.List; import java.util.Map; import com.mybatis_demo.domain.User; import com.mybatis_demo.domain.UserVo; public interface UserMapper { //mybatis使用mapper动态代理 //4大原则，一个注意 //1.接口中的方法名需要与对应mapper.xml的id一致 //2.接口中的返回值需要与对应mapper.xml的返回值类型保持一致 //3.接口中的参数需要与对应mapper.xml的参数类型、个数、参数名保持一致 //4.对应mapper.xml的名字空间需要修改成对应接口的全包名 //注意：mapper动态代理根据返回值类型,mybatis会自动选择调用selectone还是selectlist.... //用list封装条件 public List selectByList(List testlist); //用数组封装条件 public List selectByArray(Integer[] ids); //用包装类中的数组封装条件 public List selectUserVoByArray(UserVo userVo); //用包装类中的list封装条件 public List selectUserVoByList(UserVo userVo); }

三、测试代码

package com.mybatis_demo.test; import java.io.IOException; import java.io.InputStream; import java.util.ArrayList; 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.mybatis_demo.domain.User; import com.mybatis_demo.domain.UserVo; import com.mybatis_demo.mapper.UserMapper; public class TestMapper { //用包装类中的list封装条件，传递参数是一个包装类 @Test public void test_selectUserVoByList() {try {//读取配置文件InputStream in = Resources.getResourceAsStream("sqlMapConfig.xml"); //创建SqlSessionFactoryBuilder对象，用来获取SqlSessionFactory对象SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder(); //利用SqlSessionFactoryBuilder对象build一个SqlSessionFactory对象SqlSessionFactory build = builder.build(in); //利用sqlSessionFactory获取session对象SqlSession session = build.openSession(); //通过session对象获取对应mapper接口UserMapper mapper = session.getMapper(UserMapper.class); List idList = new ArrayList(); idList.add(5); idList.add(3); idList.add(123); idList.add(19); UserVo userVo = new UserVo(); userVo.setIdList(idList); List users = mapper.selectUserVoByList(userVo); for (User user : users) {System.out.println(user); }} catch (IOException e) {e.printStackTrace(); } } //用包装类中的array封装条件，传递参数是一个包装类 @Test public void test_selectUserVoByArray() {try {//读取配置文件InputStream in = Resources.getResourceAsStream("sqlMapConfig.xml"); //创建SqlSessionFactoryBuilder对象，用来获取SqlSessionFactory对象SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder(); //利用SqlSessionFactoryBuilder对象build一个SqlSessionFactory对象SqlSessionFactory build = builder.build(in); //利用sqlSessionFactory获取session对象SqlSession session = build.openSession(); //通过session对象获取对应mapper接口UserMapper mapper = session.getMapper(UserMapper.class); Integer[] ids = new Integer[]{5,9,30}; UserVo userVo = new UserVo(); userVo.setIds(ids); List users = mapper.selectUserVoByArray(userVo); for (User user : users) {System.out.println(user); }} catch (IOException e) {e.printStackTrace(); } } //用数组封装条件，传递参数是一个数组 @Test public void test_selectByArray() {try {//读取配置文件InputStream in = Resources.getResourceAsStream("sqlMapConfig.xml"); //创建SqlSessionFactoryBuilder对象，用来获取SqlSessionFactory对象SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder(); //利用SqlSessionFactoryBuilder对象build一个SqlSessionFactory对象SqlSessionFactory build = builder.build(in); //利用sqlSessionFactory获取session对象SqlSession session = build.openSession(); //通过session对象获取对应mapper接口UserMapper mapper = session.getMapper(UserMapper.class); Integer[] ids = new Integer[]{5,9,30}; List users = mapper.selectByArray(ids); for (User user : users) {System.out.println(user); }} catch (IOException e) {e.printStackTrace(); } } //用list封装条件，传递参数是一个list集合 @Test public void test_selectByList() {try {//读取配置文件InputStream in = Resources.getResourceAsStream("sqlMapConfig.xml"); //创建SqlSessionFactoryBuilder对象，用来获取SqlSessionFactory对象SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder(); //利用SqlSessionFactoryBuilder对象build一个SqlSessionFactory对象SqlSessionFactory build = builder.build(in); //利用sqlSessionFactory获取session对象SqlSession session = build.openSession(); //通过session对象获取对应mapper接口UserMapper mapper = session.getMapper(UserMapper.class); List list = new ArrayList(); list.add(5); list.add(3); list.add(123); list.add(19); List users = mapper.selectByList(list); for (User user : users) {System.out.println(user); }} catch (IOException e) {e.printStackTrace(); } }}

四、总结 1.如果你传参的时候直接传一个数组，那么使用foreach遍历时collection=“array”,这里是固定写法，即这里的array与你的实参名无关
2.如果你传参的时候直接传一list集合，那么使用foreach遍历时collection=“list”,这里是固定写法，即这里的list与你的实参名无关
3.如果你传参的时候直接传一个含有数组成员变量的类，那么使用foreach遍历时collection=“你的变量名”,这里不再是固定写法，即这里的命名取决于成员变量的变量名，例如：成员变量名是test,那么就是collection=“test”
4.如果你传参的时候直接传一个含有list集合成员变量的类，跟3的情况一样
【mybatis使用foreach遍历list集合或者array数组方式】以上为个人经验，希望能给大家一个参考，也希望大家多多支持脚本之家。