mybatis 中resultType与resultMap区别

mybatis中要返回如下对象的List集合:

public class Host {

private String hostType;

private String hostAddr;

public String getHostType() {
return hostType;
}

public void setHostType(String hostType) {
this.hostType = hostType;
}

public String getHostAddr() {
return hostAddr;
}

public void setHostAddr(String hostAddr) {
this.hostAddr = hostAddr;
}

}

如果对应的表结构是:

CREATE TABLE `host` (
  `host_type` varchar(32) NOT NULL COMMENT '主机类型',
  `host_addr` varchar(128) NOT NULL COMMENT '主机地址',
)

用resultMap返回xml中应当这样写:

<resultMap type="net.flyingfat.common.biz.domain.Host" id="hostResult">    
    <result column="host_type" property="hostType"/>    
    <result column="host_addr" property="hostAddr"/>    
</resultMap> 

<select id="getHost"  resultMap="hostResult">  
    SELECT * FROM host
</select>

用resultType返回，xml中仅仅改为

<select id="getHost"  resultType="net.flyingfat.common.biz.domain.Host">  
    SELECT * FROM host
</select>

是不够的，表结构也要改为

CREATE TABLE `host` (
  `hostType` varchar(32) NOT NULL COMMENT '主机类型',
  `hostAddr` varchar(128) NOT NULL COMMENT '主机地址'
) 

结论:如果数据表中的字段包含下划线这种写法，最好还是用resultMap去返回；resultType返回必须保证数据库字段跟java对象的字段大小写一致。