Day64---WebDebug的使用和三层优化完结

快来打我* 2023-02-26 03:29 15阅读 0赞

## 1.Debug的使用 ##

1.在想要检查的句子前加断点  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L21tbW1tbW1tbW16_size_16_color_FFFFFF_t_70]  
2.执行Debug  
3.按F6执行下一句  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L21tbW1tbW1tbW16_size_16_color_FFFFFF_t_70 1]  
此时看到student为空

## 2jsp中让表单变为只读 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L21tbW1tbW1tbW16_size_16_color_FFFFFF_t_70 2]

## 4DBUtil新增的几个方法 ##

**①**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L21tbW1tbW1tbW16_size_16_color_FFFFFF_t_70 3]  
**②**![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L21tbW1tbW1tbW16_size_16_color_FFFFFF_t_70 4]  
**③**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L21tbW1tbW1tbW16_size_16_color_FFFFFF_t_70 5]  
**④**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L21tbW1tbW1tbW16_size_16_color_FFFFFF_t_70 6]  
**⑤**![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L21tbW1tbW1tbW16_size_16_color_FFFFFF_t_70 7]  
![在这里插入图片描述][20200714100333349.png]

**这些方法使得三层优化**

## 5MYsql的rewnumber排序 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L21tbW1tbW1tbW16_size_16_color_FFFFFF_t_70 8]

## 6分页实现 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L21tbW1tbW1tbW16_size_16_color_FFFFFF_t_70 9]  
1.用mysql实现rownum并且按sno排序  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L21tbW1tbW1tbW16_size_16_color_FFFFFF_t_70 10]  
**查看一下页面长度为5，第二页**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L21tbW1tbW1tbW16_size_16_color_FFFFFF_t_70 11]  
2.先写DBUtil的查询数据总数  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L21tbW1tbW1tbW16_size_16_color_FFFFFF_t_70 12]  
3.写完DBUtil写Dao的接口  
![在这里插入图片描述][20200714163903618.png]  
4.写完Dao的接口写Dao的实现类  
**①**  
![在这里插入图片描述][20200714164125582.png]  
**②**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L21tbW1tbW1tbW16_size_16_color_FFFFFF_t_70 13]  
5.Dao的实现类写完写service接口  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L21tbW1tbW1tbW16_size_16_color_FFFFFF_t_70 14]  
6.service接口写完写service实现类

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[20200714100333349.png]: /images/20230209/366d0973e73d40069083e3ca0f57d7ef.png
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[20200714163903618.png]: /images/20230209/2baf010969f24202bc5ef1ba7cd0c591.png
[20200714164125582.png]: /images/20230209/46f69f3bb4374158b19627efccc95dc7.png
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