ibatis简单例子求助。
以前没学过ibatis的,虽然知道这东西将要被淘汰,但是现在的工作环境下用的就是ibatis。所以想想还是学学吧。以前只是调用人家写好的现成的dao层的。
今天试了一个例子,报错空指针,求助。
xml文件:
public static void main(String[] args) {
try {
com.ibatis.sqlmap.client.SqlMapClient sqlMap = null;
String resource = "sqlmap.xml";
Reader reader = Resources.getResourceAsReader(resource);
sqlMap = SqlMapClientBuilder.buildSqlMapClient(reader);
// 显示一条记录
//getNameSpace() + "." + sqlName
//第一种方式,
List<User> list = (List<User>) sqlMap.queryForList("test/test_user.getUser","10");
System.out.println(list.get(0).getName());
//第二种方式
//User user = (User) sqlMap.queryForObject("test/test_user.getUser","10");
//System.out.println(user.getName());
} catch (Exception e) {
e.printStackTrace();
}
}
FROM test_user
WHERE id = #value#
</select>
的参数名称对应
[解决办法]
Map args = new HashMap();
args.put("value", "10");
List<User> list = (List<User>) sqlMap.queryForList("test/test_user.getUser",args);
<select id="getUser" parameterClass="map" resultClass="user">
SELECT id,name,descs,address
FROM test_user
WHERE id = #value#
</select>
id,name,descs,address这个值要跟user严格对应才行的!
[解决办法]
parameterClass="int"
改成parameterClass="Integer"
试一试吧
[解决办法]
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE sqlMap PUBLIC "-//iBATIS.com//DTD sql Map 2.0//EN" "http://ibatis.apache.org/dtd/sql-map-2.dtd">
<sqlMap namespace="test/test_user">
<typeAlias alias="user" type="test.entity.User" />
<!-- Use primitive wrapper type (e.g. Integer) as parameter and allow results
to be auto-mapped results to Person object (Java Bean) properties -->
<select id="getUser" parameterClass="int" resultClass="user">
SELECT id,name,descs,address
FROM test_user
WHERE id = #value#
</select>
<select id="getUser" parameterClass="int" resultMap="user">
SELECT id,name,descs,address
FROM test_user
WHERE id = #value#
</select>
</sqlMap>
resultClass 改成 resultMap
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE sqlMap PUBLIC "-//iBATIS.com//DTD sql Map 2.0//EN" "http://ibatis.apache.org/dtd/sql-map-2.dtd">
<sqlMap namespace="test/test_user">
<typeAlias alias="user" type="" />
<!-- Use primitive wrapper type (e.g. Integer) as parameter and allow results
to be auto-mapped results to Person object (Java Bean) properties -->
<resultMap id="user" class="test.entity.User" >
<result column="id" property="id" jdbcType="DOUBLE" />
<result column="name" property="name" jdbcType="VARCHAR" />
<result column="descs" property="descs" jdbcType="VARCHAR" />
<result column="address" property="address" jdbcType="VARCHAR" />
</resultMap>
<select id="getUser" parameterClass="int" resultClass="user">
SELECT id,name,descs,address
FROM test_user
WHERE id = #value#
</select>
<select id="getUser" parameterClass="int" resultMap="user">
SELECT id,name,descs,address
FROM test_user
WHERE id = #value#
</select>
</sqlMap>
resultClass 改成 resultMap