【数组下标越界，空指针异常 _mybatis 】

数组下标越界，空指针异常
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mybatis
详细描述
错误截图
源码




package org.sang.db;

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 java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.util.Properties;

/**
 * Created by sang on 17-1-13.
 */
public class DBUtils {
    private static  SqlSessionFactory sqlSessionFactory = null;
    private static final Class CLASS_LOCK = DBUtils.class;

    public static  SqlSessionFactory initSqlSessionFactory() {
        InputStream is = null;
        try {
            is = Resources.getResourceAsStream("mybatis-conf.xml");
        } catch (IOException e) {
            e.printStackTrace();
        }
        synchronized (CLASS_LOCK) {
            if (sqlSessionFactory == null) {
                sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
            }
        }
        return sqlSessionFactory;
    }

    public static SqlSession openSqlSession() {
        if (sqlSessionFactory == null)
            initSqlSessionFactory2();
        return sqlSessionFactory.openSession();
    }

    public static  SqlSessionFactory initSqlSessionFactory2() {
        InputStream cfgStream = null;
        Reader cfgReader = null;
        InputStream proStream = null;
        Reader proReader = null;
        Properties properties = null;
        try {
            cfgStream = Resources.getResourceAsStream("mybatis-conf.xml");
            cfgReader = new InputStreamReader(cfgStream);
            proStream = Resources.getResourceAsStream("db.properties");
            proReader = new InputStreamReader(proStream);
            properties = new Properties();
            properties.load(proReader);
            //获取密文用户名和密码
            String username = properties.getProperty("username");
            String password = properties.getProperty("password");
            //解密
            properties.setProperty("username", ((String) username).substring(0, username.indexOf("-")));
            properties.setProperty("password", ((String) password).substring(0, password.indexOf("-")));
        } catch (IOException e) {
            e.printStackTrace();
        }
        synchronized (CLASS_LOCK) {
            if (sqlSessionFactory == null) {
                sqlSessionFactory = new SqlSessionFactoryBuilder().build(cfgReader,properties);
            }
        }
        return sqlSessionFactory;
    }
}

以上为工具类
  @Test
    public void test1() {
        SqlSession sqlSession = null;
        try {
            sqlSession = DBUtils.openSqlSession();
            UserMapper mapper = sqlSession.getMapper(UserMapper.class);
            List<User> list = mapper.getUser("西安");
            System.out.println(list);
            for (User user : list) {
                System.out.println(user);
            }
            sqlSession.commit();
        } catch (Exception e) {
            System.err.println(e.getMessage());
            // sqlSession.rollback();
        } finally {
            if (sqlSession != null) {
                sqlSession.close();
            }
        }
    }
以上为测试方法
public List<User> getUser(@Param("address") String address);
以上为被调用的接口里面的方法 <resultMap id="u" type="org.sang.bean.User">
        <result column="user_name" property="username"/>
    </resultMap>
    <select id="getUser" resultMap="u" parameterType="String">
        select * from user2
        <if test="address!=null and address !=''">
            WHERE address LIKE concat('%',#{address},'%')
        </if>
    </select>
以上是被执行的sql
编辑于2024-11-24
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可能是查询之后是空指针，如果有空指针的情况，需要先判空！

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编辑于2019-04-20
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