Mybatis returningHashMap

Question

I am new to MyBatis. Could anyone help me to resolve this. Thank you.

I created a table named "CodeValue" with columns like "Code","Value" etc. I am retrieving the columns "Code","Value" from the table using mybatis selectMap() method which should return HashMap with key "Code" and value "Value" as follows

<select id="getResults" parameterType="java.util.Map" resultType="java.util.HashMap">
   select "Code","Value" from "CodeValue"
</select

 Map<String, String> CodeValueMap = getSqlSession().selectMap("getResults", null, "Code");

I defined POJO as below

class CodeValue
{
  private String code;
  private String value;
  ....
  ...

  public String getCode() {
    return code;
  }

  public void setCode(String code) {
    this.code = code;
  }

  public String getValue() {
    return value;
  }

  public void setValue(String value) {
    this.value = value;
  }

  public String getKey() {
    return "code";
  }


  public String getDefaultSortColumn() {
    return code;
  }


  public String getUniqueKey() {
    return code;
  }
  ...
  ...
  ...

}

when I run the code I am getting results like below

{CODE1={Value=A, Code=CODE1}, CODE2={Value=B, Code=CODE2}, CODE3={Value=C, Code=CODE3}, CODE4={Value=D, Code=CODE4}, CODE5={Value=E, Code=CODE5}, CODE6={Value=F, Code=CODE6}, CODE7={Value=G, Code=CODE7}}

but I want results as follows

{{CODE1=A},{CODE2=B},{CODE3=C},{CODE4=D},{CODE5=E},{CODE6=F},{CODE7=G}

Thank You

Answer 1

MyBatis may not be able to return a Map directly in the form you need.
But it is not so hard to convert the result.

If you call selectList() [1], MyBatis may return a list of Maps.

[{Value=A, Code=CODE1},
{Value=B, Code=CODE2},
{Value=C, Code=CODE3}]

And the below is an example code that performs the conversion.

List<Map<String, Object>> maps = sqlSession.selectList("getResults");
Map<String, String> map = maps.stream()
  .collect(Collectors.toMap(
    m -> (String) m.get("CODE"),
    m -> (String) m.get("VALUE")));

assertEquals("A", map.get("Code1"));
assertEquals("B", map.get("Code2"));
assertEquals("C", map.get("Code3"));

[1] selectMap() is a method for very specific usage.