MyBatis学习一
MyBatis是弱项，所以需要补一下，那么就做个测试
先准备下jar包，如图：
只是为了学MyBatis就没必要弄其他那么多了，Junit启动就可以了。先配置一个log4j，找之前的文件复制了一个，如下：
log4j.rootLogger =DEBUG,stdout
log4j.appender.stdout = org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target = System.out
log4j.appender.stdout.layout = org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern = %-d{yyyy-MM-dd HH:mm:ss} [ %t:%r ] - [ %p ] %m%n然后就是mybaits-conf.xml
建表，随便弄一个测试一下，sql如下：
create table T_USER
(
USERID NUMBER not null,
USERNAME VARCHAR2(20),
PASSWORD VARCHAR2(20),
REALNAME VARCHAR2(20),
DID NUMBER,
JID NUMBER
)package cn.hd.po;
public class User {
private int userid;
private String username;
private String password;
private String realname;
private int jid;
private int did;
/**
* @return the jid
*/
public int getJid() {
return jid;
}
/**
* @param jid the jid to set
*/
public void setJid(int jid) {
this.jid = jid;
}
/**
* @return the did
*/
public int getDid() {
return did;
}
/**
* @param did the did to set
*/
public void setDid(int did) {
this.did = did;
}
/**
* @return the userid
*/
public int getUserid() {
return userid;
}
/**
* @param userid
* the userid to set
*/
public void setUserid(int userid) {
this.userid = userid;
}
/**
* @return the username
*/
public String getUsername() {
return username;
}
/**
* @param username
* the username to set
*/
public void setUsername(String username) {
this.username = username;
}
/**
* @return the password
*/
public String getPassword() {
return password;
}
/**
* @param password
* the password to set
*/
public void setPassword(String password) {
this.password = password;
}
/**
* @return the realname
*/
public String getRealname() {
return realname;
}
/**
* @param realname
* the realname to set
*/
public void setRealname(String realname) {
this.realname = realname;
}
}
package cn.hd.dao;
import java.util.List;
import cn.hd.po.User;
public interface UserMapper {
List queryAll();
User findById(int userid);
}
package cn.hd.test;
import java.io.Reader;
import java.util.List;
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.apache.log4j.Logger;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import cn.hd.po.User;
public class TestMyBatis {
Logger logger=Logger.getLogger(TestMyBatis.class);
SqlSession session ;
@Before
public void setUp() throws Exception {
logger.info("单元测试开始");
// 1、加载配置文件
Reader reader = Resources.getResourceAsReader("mybaits-conf.xml");
SqlSessionFactory factory = new SqlSessionFactoryBuilder()
.build(reader);
// 2)
session = factory.openSession();
}
@After
public void tearDown() throws Exception {
session.close();
logger.info("单元测试结束");
}
@Test
public void testFindById() {
User user=session.selectOne("cn.hd.dao.UserMapper.findById", 2);
System.out.println(user.getRealname());
}
@Test
public void testFindAll() {
List user=session.selectList("cn.hd.dao.UserMapper.queryAll");
for(User u :user)
{
System.out.println(u.getRealname());
}
}
}
ok，最后来一个错误总结。
org.apache.ibatis.exceptions.TooManyResultsException: Expected one result (or null) to be returned by selectOne(), but found: 2
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectOne(DefaultSqlSession.java:81)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectOne(DefaultSqlSession.java:71)
at cn.hd.test.TestMyBatis.testFindAll(TestMyBatis.java:42
org.apache.ibatis.exceptions.PersistenceException:
### Error querying database. Cause: org.apache.ibatis.type.TypeException: Could not set parameters for mapping: ParameterMapping{property='vlues', mode=IN, javaType=class java.lang.Integer, jdbcType=null, numericScale=null, resultMapId='null', jdbcTypeName='null', expression='null'}. Cause: org.apache.ibatis.type.TypeException: Error setting null for parameter #1 with JdbcType OTHER . Try setting a different JdbcType for this parameter or a different jdbcTypeForNull configuration property. Cause: java.sql.SQLException: 无效的列类型
### The error may exist in cn/hd/dao/UserMapper.xml
### The error may involve cn.hd.dao.UserMapper.findById-Inline
### The error occurred while setting parameters
### SQL: select * from t_user where userid=?
### Cause: org.apache.ibatis.type.TypeException: Could not set parameters for mapping: ParameterMapping{property='vlues', mode=IN, javaType=class java.lang.Integer, jdbcType=null, numericScale=null, resultMapId='null', jdbcTypeName='null', expression='null'}. Cause: org.apache.ibatis.type.TypeException: Error setting null for parameter #1 with JdbcType OTHER . Try setting a different JdbcType for this parameter or a different jdbcTypeForNull configuration property. Cause: java.sql.SQLException: 无效的列类型
at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:30)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:150)
Caused by: org.apache.ibatis.type.TypeException: Could not set parameters for mapping: ParameterMapping{property='vlues', mode=IN, javaType=class java.lang.Integer, jdbcType=null, numericScale=null, resultMapId='null', jdbcTypeName='null', expression='null'}. Cause: org.apache.ibatis.type.TypeException: Error setting null for parameter #1 with JdbcType OTHER . Try setting a different JdbcType for this parameter or a different jdbcTypeForNull configuration property. Cause: java.sql.SQLException: 无效的列类型
at org.apache.ibatis.scripting.defaults.DefaultParameterHandler.setParameters(DefaultParameterHandler.java:89)
... 29 more
Caused by: org.apache.ibatis.type.TypeException: Error setting null for parameter #1 with JdbcType OTHER . Try setting a different JdbcType for this parameter or a different jdbcTypeForNull configuration property. Cause: java.sql.SQLException: 无效的列类型
at org.apache.ibatis.type.BaseTypeHandler.setParameter(BaseTypeHandler.java:47)
at org.apache.ibatis.scripting.defaults.DefaultParameterHandler.setParameters(DefaultParameterHandler.java:87)
... 38 more
Caused by: java.sql.SQLException: 无效的列类型
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:112)
... 39 more