1.7 Java notes: Maven error resolution, spring object creation, idea operation / Java syntax error reporting

Time:2021-1-25

Idea の Maven error

Software prompt: plugin xxx not found / dependency xxx not found

One of the reasons: if you just installed idea, there is no “download good dependencies” folder in maven, which comes with idea, so the download process is blocked.


Solution: if there is no related folder, create one. Of course, you can’t create one manually setting.xml Paste the relevant code and create it automatically the next time you start idea. Adding code not only creates a folder, but also lets idea know the download address of the local repository.


Cause evidence: when encountering errors, it was around 21:40. When trying to solve the problem, I set the directory at 21:57, and then all the dependencies ran into these directories after 21:57


resolvent:

1. Find setting.xml Documents. (search can be used from the Maven home folder)
2. Add code
< localrepository > your idea directory

**
Position in < setting xsi:schemaLocation…. ……… >Next line
1.7 Java notes: Maven error resolution, spring object creation, idea operation / Java syntax error reporting

3. Restart idea

Idea operation skills

1. Quick prompt codealt+/
2. Operation class / interfacealt+enter
3. Add resource files quicklyalt+insert


Object creation in spring

1. Spring creates objects in the form of XML code
2. The object in spring is called bean
3. Simple and in-depth study: in sring source code, first new object, and then put it into the map collection.
4. Create bean format: < bean id = “unique ID” class “specified class” >

Java error

1. Add “()” after the method name.

@Test prompt: annotations are not allowed here

Since “()” was not added, the comment “@ test” added in front of it also reported an error. It can be seen that parameter / “(null parameter)” is a necessary part of a method. Without it, there is no method. There is no method “@ test” to report an error. It reports an error on the basis of “I didn’t comment anything”.