Mybatis entry - additions and deletions to the basic way of investigation, CRUD mapper dynamic proxy mode, the type of converter

A basic way of additions and deletions to the investigation:

1.mybatis convention: parameterType input parameters and output parameters resulrType in the form of only one.

2. If the input / output parameters: a simple type (plus eight basic types String) may be used any of the placeholders, # {xxx};

If the object type, the property of the object must be, attribute name # {}.

3. Output parameter: if the return value is an object type (such as the Person), regardless of whether one or a plurality of return, are written in resultType org.lanqiao.entity.Person, i.e. resultType = "org.lanqiao.entity.Person".

4. Note: a. If using JDBC commit transaction schemes require manual lifting, i.e. session.commit ();.

b. All tags <select>. <update> and the like, must have sql statement, but optional parameters sql

There sql parameters: session.insert (statement, parameter values);

CRUD two .mapper dynamic proxy mode (MyBatis interface development):

Principles: convention over configuration

Hard-coded: abc.java

Configuration conf=new Configuration();

conf.setName("myProject");

Configuration: abc.xml

<name>myProject</name>

Conventions: The default value is myProject

Specific steps to achieve:

1. Basic environment: mybatis.jar / ojdbc.jar / conf.xml / mapper.xml

2. (difference) prescribed goals: Statement omitted, i.e., by convention, to be positioned directly sql statement.

. A interfaces, interface methods must follow the following conventions:

1) The method of the same name and the id value mapper.xml tag file;

2) consistent with the type of input parameters parameterType mapper.xml method and file labels;

Return value consistent resultType mapper.xml file type tag 3) of the process;

In addition to these conventions, to implement SQL label correspondence interface methods and Mapper.xml in, you also need the following point:

1) namespace value is the full name of the class interface (Interface -mapper.xml one correspondence)

During the matching process agreed :()

1. Locate the file according to the interface name mapper.xml

2. Find (id = sql method name tag) sql tag mapper.xml file name of the method according to the interface

Habit: SQL mapping file (mapper.xml) and interfaces in the same package (note modify the path load mapper.xml of conf.xml file)

代码：PersonMappe personMapper=session.getMapper(PersonMapper.class);

personMapper. Methods

optimization:

1. The configuration information may be placed in a separate file db.properties then introduced into the dynamic

db.properties;

a = v

After introduction of the use of $ {key}

2.Mybaites global parameters

3. Alias :( capitalization does not matter when you define an alias)

a. providing a single alias

b. Set up the bulk alias

In addition to custom alias outside, MyBatis also built some common aliases like.

Three type converter:

1.MyBatis comes with some common types of processors

int——number

2. Custom Types processor MyBatis

Java-- database (jdbc type)

Custom type converter (boolean-number) steps of:

. A converter created: the need to implement the interface TypeHandler

To achieve the conversion has two options: (1) interface to implement the interface TypeHandler

(2) 继承 BaseTypeHandler

b. Configure conf.xml

Note: You must be capitalized when setting Integer.

resultMap can achieve two functions:

1. Type Conversion

2. Properties - mapping between fields

Mybatis entry - additions and deletions to the basic way of investigation, CRUD mapper dynamic proxy mode, the type of converter

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