mybatis @Intercepts的用法解读

时间：2022-09-18 23:14:57

mybatis @Intercepts的用法

1.拦截器类

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package com.testmybatis.interceptor;
import java.util.Properties;
import org.apache.ibatis.executor.Executor;
import org.apache.ibatis.mapping.BoundSql;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.SqlSource;
import org.apache.ibatis.plugin.Interceptor;
import org.apache.ibatis.plugin.Intercepts;
import org.apache.ibatis.plugin.Invocation;
import org.apache.ibatis.plugin.Plugin;
import org.apache.ibatis.session.ResultHandler;
import org.apache.ibatis.session.RowBounds;
import org.apache.log4j.Logger;
 
@Intercepts({ @org.apache.ibatis.plugin.Signature(type = Executor.class, method = "query", args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class }) })
public class SqlInterceptor implements Interceptor {
    
    private Logger log=Logger.getLogger(getClass());
    public Object intercept(Invocation invocation) throws Throwable {
        // TODO Auto-generated method stub
 
        log.info("Interceptor......");
 
        // 获取原始sql语句
        MappedStatement mappedStatement = (MappedStatement) invocation.getArgs()[0];
        Object parameter = invocation.getArgs()[1];
        BoundSql boundSql = mappedStatement.getBoundSql(parameter);
        String oldsql = boundSql.getSql();
        log.info("old:"+oldsql);
 
        // 改变sql语句
        BoundSql newBoundSql = new BoundSql(mappedStatement.getConfiguration(), oldsql + " where id=1",
                boundSql.getParameterMappings(), boundSql.getParameterObject());
        MappedStatement newMs = copyFromMappedStatement(mappedStatement, new BoundSqlSqlSource(newBoundSql));
        invocation.getArgs()[0] = newMs;
 
        // 继续执行
        Object result = invocation.proceed();
        return result;
    }
 
    public Object plugin(Object target) {
        // TODO Auto-generated method stub
        return Plugin.wrap(target, this);
    }
 
    public void setProperties(Properties properties) {
        // TODO Auto-generated method stub
    }
 
    // 复制原始MappedStatement
    private MappedStatement copyFromMappedStatement(MappedStatement ms, SqlSource newSqlSource) {
        MappedStatement.Builder builder = new MappedStatement.Builder(ms.getConfiguration(), ms.getId(), newSqlSource,
                ms.getSqlCommandType());
        builder.resource(ms.getResource());
        builder.fetchSize(ms.getFetchSize());
        builder.statementType(ms.getStatementType());
        builder.keyGenerator(ms.getKeyGenerator());
        if (ms.getKeyProperties() != null) {
            for (String keyProperty : ms.getKeyProperties()) {
                builder.keyProperty(keyProperty);
            }
        }
        builder.timeout(ms.getTimeout());
        builder.parameterMap(ms.getParameterMap());
        builder.resultMaps(ms.getResultMaps());
        builder.cache(ms.getCache());
        builder.useCache(ms.isUseCache());
        return builder.build();
    }
 
    public static class BoundSqlSqlSource implements SqlSource {
        BoundSql boundSql;
        public BoundSqlSqlSource(BoundSql boundSql) {
            this.boundSql = boundSql;
        }
 
        public BoundSql getBoundSql(Object parameterObject) {
            return boundSql;
        }
    }
}

2.拦截器配置

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<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
  PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
  "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
 
    <plugins>
        <plugin interceptor="com.testmybatis.interceptor.SqlInterceptor" />
    </plugins>
 
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC" />
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.cj.jdbc.Driver" />
                <property name="url"
                    value="jdbc:mysql://127.0.0.1:3306/test?serverTimezone=UTC&amp;useUnicode=true&amp;characterEncoding=utf-8&amp;useSSL=true" />
                <property name="username" value="root" />
                <property name="password" value="123456" />
            </dataSource>
        </environment>
    </environments>
    
    <mappers>
        <mapper resource="com/testmybatis/dao/TestMapper.xml" />
    </mappers>   
</configuration>

3.测试接口及配置

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package com.testmybatis.model;
import java.io.Serializable;
public class Test implements Serializable{
    /**
     *
     */
    private static final long serialVersionUID = 1L;
    private int id;
    private String name;
 
    public int getId() {
        return id;
    }
 
    public void setId(int id) {
        this.id = id;
    }
 
    public String getName() {
        return name;
    }
 
    public void setName(String name) {
        this.name = name;
    }
    
    public String toString(){
        return "id:"+id+" name:"+name;
    }
}
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package com.testmybatis.dao;
import java.util.List;
import org.apache.ibatis.annotations.Select;
import com.testmybatis.model.Test; 
public interface TestMapper {
    public List<Test> test();
}
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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.testmybatis.dao.TestMapper">
 
    <select id="test" resultType="com.testmybatis.model.Test">
        select * from test
    </select>
 
</mapper>

4.测试

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try {
        String resource = "com/testmybatis/mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        SqlSession session = sqlSessionFactory.openSession();
        try {
            TestMapper mapper=session.getMapper(TestMapper.class);
            List<Test> tests=mapper.test();
            session.commit();
            log.info(JSON.toJSONString(tests));
            
        } finally {
            session.close();
        }
 
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

5.结果

配置了拦截器的情况下

2018-08-07 14:14:18 DEBUG [com.testmybatis.dao.TestMapper.test] ==> Preparing: select * from test where id=1

2018-08-07 14:14:18 DEBUG [com.testmybatis.dao.TestMapper.test] ==> Parameters:

2018-08-07 14:14:18 DEBUG [com.testmybatis.dao.TestMapper.test] <== Total: 1

2018-08-07 14:14:18 INFO [com.testmybatis.testlanjie] [{"id":1,"name":"adb"}]

没配置拦截器的情况下

2018-08-07 14:15:48 DEBUG [com.testmybatis.dao.TestMapper.test] ==> Preparing: select * from test

2018-08-07 14:15:48 DEBUG [com.testmybatis.dao.TestMapper.test] ==> Parameters:

2018-08-07 14:15:48 DEBUG [com.testmybatis.dao.TestMapper.test] <== Total: 8

2018-08-07 14:15:48 INFO [com.testmybatis.testlanjie] [{"id":1,"name":"adb"},{"id":2,"name":"dafdsa"},{"id":3,"name":"dafa"},{"id":4,"name":"fffff"},{"id":16,"name":"test"},{"id":17,"name":"test"},{"id":18,"name":"test"},{"id":19,"name":"zhenshide"}]

mybatis @Intercepts小例子

这只是一个纯碎的mybatis的只针对@Intercepts应用的小列子，没有和spring做集成。

1.工作目录

mybatis @Intercepts的用法解读

2.数据库mysql

建立一个数据库表、实体对象User、UserMapper.java、UserMapper.xml省略。

使用mybatis自动代码生成工具生成：mybatis-generator-core-1.3.2。（此处略）

3.拦截器

MyInterceptor.java

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package com.tiantian.mybatis.interceptor;
import java.sql.Connection;
import java.util.Properties;
import org.apache.ibatis.executor.Executor;
import org.apache.ibatis.executor.statement.StatementHandler;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.plugin.Interceptor;
import org.apache.ibatis.plugin.Intercepts;
import org.apache.ibatis.plugin.Invocation;
import org.apache.ibatis.plugin.Plugin;
import org.apache.ibatis.plugin.Signature;
import org.apache.ibatis.session.ResultHandler;
import org.apache.ibatis.session.RowBounds;
@Intercepts( {
    @Signature(method = "query", type = Executor.class, args = {
           MappedStatement.class, Object.class, RowBounds.class,
           ResultHandler.class }),
    @Signature(method = "prepare", type = StatementHandler.class, args = { Connection.class }) })
public class MyInterceptor implements Interceptor {
    @Override
    public Object intercept(Invocation invocation) throws Throwable {
        Object result = invocation.proceed();
        System.out.println("Invocation.proceed()");
        return result;
    }
    @Override
    public Object plugin(Object target) {
        // TODO Auto-generated method stub
        return Plugin.wrap(target, this);
    }
    @Override
    public void setProperties(Properties properties) {
        String prop1 = properties.getProperty("prop1");
        String prop2 = properties.getProperty("prop2");
        System.out.println(prop1 + "------" + prop2);
    }
}

4.配置文件

mybatis-config.xml

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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration
  PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
  "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <properties resource="jdbc.properties"></properties>
    <typeAliases>
       <package name="com.tiantian.mybatis.model"/>
    </typeAliases>
    <plugins>
       <plugin interceptor="com.tiantian.mybatis.interceptor.MyInterceptor">
           <property name="prop1" value="prop1"/>
           <property name="prop2" value="prop2"/>
       </plugin>
    </plugins>
    <environments default="development">
       <environment id="development">
           <transactionManager type="JDBC" />
           <dataSource type="POOLED">
              <property name="driver" value="${driver}" />
              <property name="url" value="${url}" />
              <property name="username" value="${username}" />
              <property name="password" value="${password}" />
           </dataSource>
       </environment>
    </environments>
    <mappers>
       <mapper resource="com/tiantian/mybatis/mapper/UserMapper.xml"/>
    </mappers>
</configuration>

5.配置文件

jdbc.properties

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driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/database_yxl
username=root
password=123456
#定义初始连接数
initialSize=0
#定义最大连接数
maxActive=20
#定义最大空闲
maxIdle=20
#定义最小空闲
minIdle=1
#定义最长等待时间
maxWait=60000

6.测试文件

TestMyBatis.java

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package com.tiantian.mybatis.service;
import org.apache.ibatis.session.SqlSession;
import com.tiantian.base.MyBatisUtil;
import com.tiantian.mybatis.domain.User;
public class TestMyBatis {
    public static void main(String[] args) {
        SqlSession session = MyBatisUtil.getSqlSession();
        /**
         * 映射sql的标识字符串，
         * com.tiantian.mybatis.mapper.userMapper是userMapper.xml文件中mapper标签的namespace属性的值，
         * selectByPrimaryKey是select标签的id属性值，通过select标签的id属性值就可以找到要执行的SQL
         */
        String statement = "com.tiantian.mybatis.mapper.UserMapper.selectByPrimaryKey";//映射sql的标识字符串
        //执行查询返回一个唯一user对象的sql
        User user = session.selectOne(statement, 1);
        System.out.println(user);
    }
}

输出结果：

prop1------prop2

Invocation.proceed()

Invocation.proceed()

[id:1;username:测试;password:sfasgfaf]

7.工具类

MyBatisUtil.java

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package com.tiantian.base;
import java.io.InputStream;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
public class MyBatisUtil {
    public static SqlSessionFactory getSqlSessionFactory() {
        String resource = "mybatis-config.xml";
        // 使用类加载器加载mybatis的配置文件（它也加载关联的映射文件）
        InputStream is = MyBatisUtil.class.getClassLoader().getResourceAsStream(resource);
        // 构建sqlSession的工厂
        SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(is);
        return sessionFactory;
    }
    public static SqlSession getSqlSession() {
        return getSqlSessionFactory().openSession();
    }
    public static SqlSession getSqlSession(boolean isAutoCommit) {
        return getSqlSessionFactory().openSession(isAutoCommit);
    }
}

以上为个人经验，希望能给大家一个参考，也希望大家多多支持服务器之家。

原文链接：https://blog.csdn.net/caideb/article/details/81480260

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