MyBatis interprets #{...} as a parameter marker in a JDBC prepared statement. MyBatis interprets ${...} as string substitution. It is important to know the difference because parameter markers cannot be used in certain places in SQL statements.
For example, you cannot use a parameter marker to specify a table name.
Given the following code:

Map<String, Object> parms = new HashMap<String, Object>(); parms.put("table", "foo"); parms.put("criteria", 37); List<Object> rows = mapper.generalSelect(parms);

<select id="generalSelect" parameterType="map"> select * from ${table} where col1 = #{criteria} </select>

MyBatis will generate the following prepared statement:

select * from foo where col1 = ? 

Important: note that use of ${...} (string substitution) presents a risk for SQL injection attacks. Also, string substitution can be problematical for complex types like dates. For these reasons, we recommend using the #{...} form whenever possible.

There are two methods. In the first (and preferred) method, you append the SQL wildcards in your Java code.
For example:

String wildcardName = "%Smi%"; List<Name> names = mapper.selectLike(wildcardName);

<select id="selectLike"> select * from foo where bar like #{value} </select>

Alternatively, you can append '%' in XML mapper using <bind /> tag.

String name = "Smi"; List<Name> names = mapper.selectLike(name);

<select id="selectLike"> <bind name="wildcardName" value="'%' + _parameter + '%'" /> select * from foo where bar like #{wildcardName} </select>

Another method is to concatenate the wildcards in your SQL. This method is less safe than the method above because of possible SQL injection.
For example:

String wildcardName = "Smi"; List<Name> names = mapper.selectLike(wildcardName);

<select id="selectLike"> select * from foo where bar like '%' || '${value}' || '%' </select>

Important: Note the use of $ vs. # in the second example!

First, code a simple insert statement like this:

<insert id="insertName"> insert into names (name) values (#{value}) </insert>

Then execute a batch in Java code like this:

List<String> names = new ArrayList<String>(); names.add("Fred"); names.add("Barney"); names.add("Betty"); names.add("Wilma"); SqlSession sqlSession = sqlSessionFactory.openSession(ExecutorType.BATCH); try { NameMapper mapper = sqlSession.getMapper(NameMapper.class); for (String name : names) { mapper.insertName(name); } sqlSession.commit(); } finally { sqlSession.close(); }

The insert method always returns an int - which is the number of rows inserted. Auto generated key values are placed into the parameter object and are available after the completion of the insert method.
For example:

<insert id="insertName" useGeneratedKeys="true" keyProperty="id"> insert into names (name) values (#{name}) </insert>

Name name = new Name(); name.setName("Fred"); int rows = mapper.insertName(name); System.out.println("rows inserted = " + rows); System.out.println("generated key value = " + name.getId());

Note that not many DB/drivers support key generation in batch operation or with multi-row insert syntax. Please refer to the DB/drivers' documentation for the details.

Java reflection does not provide a way to know the name of a method parameter so MyBatis names them by default like: param1, param2...
If you want to give them a name use the @param annotation this way:

import org.apache.ibatis.annotations.Param; public interface UserMapper { User selectUser(@Param("username") String username, @Param("hashedPassword") String hashedPassword); }

Now you can use them in your xml like follows:

<select id=”selectUser” resultType=”User”> select id, username, hashedPassword from some_table where username = #{username} and hashedPassword = #{hashedPassword} </select>

To map the following results

to the following java object,

public class SomeBean { private Integer id; private List<String> strings; // getters and setters }

the result map should look as follows.

<resultMap id="" type="SomeBean"> <id column="id" property="id" /> <collection property="strings" ofType="string" javaType="list"> <result column="str" /> </collection> </resultMap>