Mapper Pass Multiple parameters

<span id="Label3"></p>The parameters of the MyBatis Mapper interface are generally an object, but what if it is not an object and has multiple parameters? Our first idea was to encapsulate the parameters into a java.util.Map type, and then write the key of the map on the comment of the method, but it is not intuitive enough to see what the parameters of this method are, and it affects the polymorphism of the Java method (the same method name, the number of parameters, or the type does not The same). The following method one and method two can solve the problem! A functional method of a DAO layer <table border="0" cellspacing="0" cellpadding="0"> <tbody> <tr> <td class="gutter">1</td> <td class="code"><code class="sql keyword">Public</code><code class="sql color2"> User</code><code class="sql plain"> selectUser(String </code><code class="sql keyword">name</code><code class="sql plain">,String area);</code></td> </tr> </tbody> </table><p><p>The corresponding Mapper.xml</p></p> <table border="0" cellspacing="0" cellpadding="0"> <tbody> <tr> <td class="gutter">123 </td> <td class="code"> <cod e class="sql plain"> < <code class="sql keyword">select </code> <code class="sql plain"> id= </code> <code class="sql string"> "selectuser" </code> <code class="sql plain"> resultmap= </code> <code class="sql string"> " Baseresultmap "</code> <code class=" SQL plain ">> </code> <code class=" sql Spaces ">     </code> <code class="sql keyword">select </code>   <code class="sql plain"> *  </code> <code class="sql keyword">from </code> <code class="sql plain"> user_user_t   </code> <code class="sql keyword">where </code> <code class="sql plain"> user_name = #{0} </code> <code class="sql color1">and </code> <code class="sql plain"> user_area=#{1} </code> <code class="sql plain"></</code> <code class="sql keyword">select </code> <code class="sql plain">> </code> </cod></td> </tr> </tbody> </table><p><p>Where #{0} represents the first parameter in the DAO layer, #{1} represents the second parameter in the DAO layer, and more parameters are consistently added.</p></p>Two<p><p>This method uses map to pass multiple Parameters.</p></p><p><p>The function method of DAO layer</p></p> <table border="0" cellspacing="0" cellpadding="0"> <tbody> <tr> <td class="gutter">1</td> <td class="code"><code class="sql keyword">Public</code><code class="sql color2"> User</code><code class="sql plain"> selectUser(Map paramMap);</code></td> </tr> </tbody> </table><p><p>The corresponding Mapper.xml</p></p> <table border="0" cellspacing="0" cellpadding="0"> <tbody> <tr> <td class="gutter">123</td> <td class="code"><code class="sql plain">< </code> <code class="sql keyword">select </code> <code class="sql plain"> id= </code> <code class="sql string"> "selectuser" </code> <code class="sql plain"> resultmap= </code> <code class="sql string"> "baseresultmap" </code> <code class="sql plain">> </code> <code class="sql spaces">    </code> <code class="sql keyword">select </code>   <code class="sql plain"> *  </code> <code class="sql keyword"> From </code> <code class="sql plain"> user_user_t   </code> <code class="sql keyword">where </code> <code class="sql plain"> user_name = #{username,jdbctype= </code> <code class="sql keyword">varchar </code> <code class="sql Plain ">} </code> <code class=" sql Color1 ">and </code> <code class=" SQL plain "> user_area=#{userarea,jdbctype= </code> <code class="sql keyword">varchar </code> <code class="sql plain">} </code> <code class="sql plain"></ </code> <code class="sql keyword">select </code> <code class="sql plain">> </code> </td> </tr> </tbody> </table><p><p>Service Layer Invocation</p></p> <table border="0" cellspacing="0" cellpadding="0"> <tbody> <tr> <td class="gutter">12345</td> <td class="code"><code class="sql plain">Private </code><code class="sql color2">User</code><code class="sql plain"> xxxSelectUser(){</code><code class="sql plain">Map paramMap=new hashMap();</code><code class="sql plain">paramMap.put(“userName”,”对应具体的参数值”);</code><code class="sql plain">paramMap.put(“userArea”,”对应具体的参数值”);</code><code class="sql color2">User</code><code class="sql color2"> user</code><code class="sql plain">=xxx. selectUser(paramMap);}</code></td> </tr> </tbody> </table><p><p>personally, This method is not intuitive enough to see the interface method can not directly know what parameters to Pass.</p></p>Three<p><p>The function method of DAO layer</p></p> <table border="0" cellspacing="0" cellpadding="0"> <tbody> <tr> <td class="gutter">1</td> <td class="code"><code class="sql keyword">Public</code><code class="sql color2"> User</code><code class="sql plain"> selectUser(@Param(“userName”)String name,@Param(“userArea”)String area);</code></td> </tr> </tbody> </table><p><p>The corresponding Mapper.xml</p></p> <table border="0" cellspacing="0" cellpadding="0"> <tbody> <tr> <td class="gutter">123</td> <td class="code"><code class="sql plain">< </code> <code class="sql keyword">select </code> <code class="sql plain"> id= </code> <code class="sql string"> "selectuser" </code> <code class="sql plain"> resultmap= </code> <code class="sql string"> "baseresultmap" </code> <code class="sql plain">> </code> <code class="sql spaces">    </code> <code class="sql keyword">select </code>   <code class="sql plain"> *  </code> <code class="sql keyword"> From </code> <code class="sql plain"> user_user_t   </code> <code class="sql keyword">where </code> <code class="sql plain"> user_name = #{username,jdbctype= </code> <code class="sql keyword">varchar </code> <code class="sql Plain ">} </code> <code class=" sql Color1 ">and </code> <code class=" SQL plain "> user_area=#{userarea,jdbctype= </code> <code class="sql keyword">varchar </code> <code class="sql plain">} </code> <code class="sql plain"></ </code> <code class="sql keyword">select </code> <code class="sql plain">>  </code> </td> </tr> </tbody> </table><p><p>Personally think this method is better, can let the developer see DAO layer method to know what kind of parameters, more intuitive, personal recommendation with this kind of scheme</p></p><p><p>Mapper Pass Multiple parameters</p></p></span>