最近在项目中应用到springboot与mybatis，在进行整合过程中遇到一些坑，在此将其整理出来，便于以后查阅与复习。
项目运行环境为：eclispe+jdk1.8+maven
搭建spring boot环境
首先建立maven project,在生成的pom文件中加入依赖，代码如下：
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
|
<parent>
<groupid>org.springframework.boot</groupid>
<artifactid>spring-boot-starter-parent</artifactid>
<version>1.5.2.release</version>
<relativepath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceencoding>utf-8</project.build.sourceencoding>
<project.reporting.outputencoding>utf-8</project.reporting.outputencoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupid>org.springframework.boot</groupid>
<artifactid>spring-boot-starter-web</artifactid>
</dependency>
<dependency>
<groupid>org.springframework.boot</groupid>
<artifactid>spring-boot-starter-test</artifactid>
</dependency>
<dependency>
<groupid>org.mybatis.spring.boot</groupid>
<artifactid>mybatis-spring-boot-starter</artifactid>
<version>1.3.0</version>
</dependency>
<dependency>
<groupid>mysql</groupid>
<artifactid>mysql-connector-java</artifactid>
<scope>runtime</scope>
</dependency>
<!--分页插件-->
<dependency>
<groupid>com.github.pagehelper</groupid>
<artifactid>pagehelper-spring-boot-starter</artifactid>
<version>1.2.1</version>
</dependency>
<!-- alibaba的druid数据库连接池 -->
<dependency>
<groupid>com.alibaba</groupid>
<artifactid>druid</artifactid>
<version>1.0.29</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupid>org.springframework.boot</groupid>
<artifactid>spring-boot-maven-plugin</artifactid>
</plugin>
<!-- mybatis generator 自动生成代码插件 -->
<plugin>
<groupid>org.mybatis.generator</groupid>
<artifactid>mybatis-generator-maven-plugin</artifactid>
<version>1.3.2</version>
<configuration>
<configurationfile>${basedir}/src/main/resources/generator/generatorconfig.xml</configurationfile>
<overwrite>true</overwrite>
<verbose>true</verbose>
</configuration>
</plugin>
</plugins>
</build>
|
配置好依赖后进行maven install,此时注意的坑：
坑一：启动maven install报错：
[error] failed to execute goal org.springframework.boot:spring-boot-maven-plugin:1.5.2.release:repackage (default) on project springboot-mybatis: execution default of goal org.springframework.boot:spring-boot-maven-plugin:1.5.2.release:repackage failed: unable to find main class -> [help 1]
[error]
[error] to see the full stack trace of the errors, re-run maven with the -e switch.
[error] re-run maven using the -x switch to enable full debug logging.
[error]
[error] for more information about the errors and possible solutions, please read the following articles:
[error] [help 1] http://cwiki.apache.org/confluence/display/maven/pluginexecutionexception
报错原因是没有启动类
解决方法:编写启动类main.java正常运行！
|
1
2
3
4
5
6
|
@springbootapplication
public class main {
public static void main(string[] args) {
springapplication.run(main.class, args);
}
}
|
坑二：启动maven install报错：
[error] failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.1:compile (default-compile) on project springboot-mybatis: compilation failure
[error] no compiler is provided in this environment. perhaps you are running on a jre rather than a jdk?
[error] -> [help 1]
[error]
[error] to see the full stack trace of the errors, re-run maven with the -e switch.
[error] re-run maven using the -x switch to enable full debug logging.
[error]
[error] for more information about the errors and possible solutions, please read the following articles:
[error] [help 1] http://cwiki.apache.org/confluence/display/maven/mojofailureexception
报错原因：项目的java环境与电脑环境不符合，例如我的新建项目运行环境为j2se-1.5,报错是在我将其改为jre1.8之后
解决方案：
右键项目——build path——configure build path——libraries——双击jre system libraries如下图所示：
选择alternate jre 如2处的下拉框只有jre，点击3处的install jres，依次经过add——standard vm——next——directory,选择本机的jdk位置点击finish
在install jres位置将默认勾选更改jdk,如下图所示，并保存。
再次maven install项目正常。如下所示：
[info] build success
[info] ------------------------------------------------------------------------
[info] total time: 3.351 s
[info] finished at: 2018-09-05t21:20:48+08:00
[info] final memory: 23m/181m
[info] ------------------------------------------------------------------------
在src/main/resources新建文件：application.yml，内容如下所示：
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
|
server:
port: 8080
spring:
datasource:
name: test
url: jdbc:mysql://localhost:3306/test
username: root
password: 123456
driver-class-name: com.mysql.jdbc.driver
## 该配置节点为独立的节点
mybatis:
mapper-locations: classpath:mapper/*.xml
#pagehelper分页插件
pagehelper:
helperdialect: mysql
reasonable: true
supportmethodsarguments: true
params: count=countsql
|
至此springboot环境搭建完毕！
逆向工程应用
首先应该注意到在pom文件中有配置逆向工程xml文件的位置：src/main/resources/generator/generatorconfig.xml
因而在src/main/resources下新建generator文件夹，并建立generatorconfig.xml文件，代码如下：
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
|
<?xml version="1.0" encoding="utf-8"?>
<!doctype generatorconfiguration public "-//mybatis.org//dtd mybatis generator configuration 1.0//en" "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">
<generatorconfiguration>
<!-- 数据库驱动:选择你的本地硬盘上面的数据库驱动包-->
<classpathentry location="e:\plugins\maven\repo\mysql\mysql-connector-java\5.1.41\mysql-connector-java-5.1.41.jar"/>
<context id="db2tables" targetruntime="mybatis3">
<commentgenerator>
<property name="suppressdate" value="true"/>
<!-- 是否去除自动生成的注释 true：是 ： false:否 -->
<property name="suppressallcomments" value="true"/>
</commentgenerator>
<!--数据库链接url，用户名、密码 -->
<jdbcconnection driverclass="com.mysql.jdbc.driver" connectionurl="jdbc:mysql://localhost/test" userid="root" password="123456">
</jdbcconnection>
<javatyperesolver>
<property name="forcebigdecimals" value="false"/>
</javatyperesolver>
<!-- 生成pojo类的位置-->
<javamodelgenerator targetpackage="com.luis.entity" targetproject="src/main/java">
<property name="enablesubpackages" value="true"/>
<property name="trimstrings" value="true"/>
</javamodelgenerator>
<!-- 生成映射文件的包名和位置-->
<sqlmapgenerator targetpackage="mapper" targetproject="src/main/resources">
<!-- enablesubpackages 是否让schema作为包的后缀-->
<property name="enablesubpackages" value="false"/>
</sqlmapgenerator>
<!-- 生成mapper接口的位置-->
<javaclientgenerator type="xmlmapper" targetpackage="com.luis.mapper" targetproject="src/main/java">
<!-- enablesubpackages 是否让schema作为包的后缀-->
<property name="enablesubpackages" value="false"/>
</javaclientgenerator>
<!-- 指定数据库表 -->
<table schema="" tablename="user"></table>
</context>
</generatorconfiguration>
|
根据个人环境将配置文件中的配置进行更改，如数据库密码，包名，对应数据库表
所用的数据库表如下：
|
1
2
3
4
5
6
7
8
9
10
11
|
drop table if exists `user`;
create table `user` (
`id` bigint(20) not null,
`name` varchar(255) not null,
`age` int(4) not null,
primary key (`id`)
) engine=innodb default charset=utf8;
insert into `user` values ('1', 'wanger', '22');
insert into `user` values ('2', 'zhangsan', '18');
insert into `user` values ('3', 'lisi', '23');
insert into `user` values ('4', 'wangwu', '21');
|
配置完成后，右键项目，选择run as——maven build——在下面两处分别填入：
goals: mybatis-generator:generate -e
profiles: generatorconfig.xml
如下图所示：
出现如下所示，代码生成成功，刷新项目即可。
[info] generating example class for table user
[info] generating record class for table user
[info] generating mapper interface for table user
[info] generating sql map for table user
[info] saving file usermapper.xml
[info] saving file userexample.java
[info] saving file user.java
[info] saving file usermapper.java
[info] ------------------------------------------------------------------------
[info] build success
[info] ------------------------------------------------------------------------
需要注意的是：逆向工程生成的代码不会覆盖，因而不能重复多次生成。
此处也有个小坑，逆向工程的代码生成后，启动项目会报如下错误：
***************************
application failed to start
***************************description:
field usermapper in com.luis.service.impl.userserviceimpl required a bean of type 'com.luis.mapper.usermapper' that could not be found.
action:
consider defining a bean of type 'com.luis.mapper.usermapper' in your configuration.
解决方案：
1、给生成的mapper接口文件前加注解：@mapper 即可解决。但需要给每一个mapper文件前加，繁琐，因而有第二种类
解决办法
2、在启动类前加@mapperscan({"com.luis.mapper"})，其中com.luis.mapper为mapper文件的所在位置。
参考自：http://412887952-qq-com.iteye.com/blog/2392672
分页应用
逆向工程已经生成了entity类，及dao层的mapper接口与*mapper.xml文件，因而/只用编写service层与web层。
首先在userservice中编写接口，代码如下：
|
1
2
3
4
|
public interface userservice {
user selectbyname(string name);
list<user> findalluser(int pagenum, int pagesize);
}
|
在userserviceimpl文件进行实现，代码如下所示：
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
|
@service
public class userserviceimpl implements userservice {
@autowired
private usermapper usermapper;
@override
public user selectbyname(string name) {
userexample example = new userexample();
criteria criteria = example.createcriteria();
criteria.andnameequalto(name);
list<user> users = usermapper.selectbyexample(example);
if (users != null && users.size() > 0) {
return users.get(0);
}
return null;
}
/**
* pagenum 开始页数
* pagesize 每页显示的数据条数
*/
@override
public list<user> findalluser(int pagenum, int pagesize) {
//将参数传给方法实现分页
pagehelper.startpage(pagenum, pagesize);
userexample example = new userexample();
list<user> list = usermapper.selectbyexample(example);
return list;
}
}
|
最后在controller层对查询结果进行接收，usercontroller代码如下：
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
|
@controller
@restcontroller
public class usercontroller {
@autowired
private userservice userservice;
@requestmapping("/test")
public user queruserbyname() {
user user = userservice.selectbyname("luis");
system.out.println(user.tostring());
return user;
}
@requestmapping("/list")
public list<user> queruser() {
list<user> list = userservice.findalluser(1, 2);
//获取分页信息
pageinfo<user> pageinfo = new pageinfo<>(list);
system.out.println("total:" + pageinfo.gettotal());
system.out.println("pages:" + pageinfo.getpages());
system.out.println("pagesize:" + pageinfo.getpagesize());
return list;
}
}
|
测试
此前在项目编写过程中已经对可能出现的错误进行了总结，最后，对项目的功能进行测试，通过加@restcontroller注解将数据传输到浏览器中。
测试mybatis与springboot，浏览器输入http://localhost:8080/test，浏览器输出：
{"id":1,"name":"wanger","age":22}
分页测试，浏览器输入http://localhost:8080/list，浏览器输出：
[{"id":1,"name":"wanger","age":22},{"id":2,"name":"zhangsan","age":18}]
eclipse输出：
total:4
pages:2
pagesize:2
项目搭建完毕，具体代码参见github
总结
以上所述是小编给大家介绍的mybatis逆向工程与分页在springboot中的应用，希望对大家有所帮助，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对服务器之家网站的支持！
原文链接：https://www.cnblogs.com/liuyi6/archive/2018/09/06/9595856.html