How to set database login information from variable?

Question

I am using MyBatis in a Java project. I know that database access information such as host, database name, username and password are stored in configuration.xml. But I would like to know if I can set these login information from inside my Java program.

It's because my application is accessing different databases on different addresses and I am configuring them in the application. Please help me.

Answer 1

The configuration xml file supports a <properties> element. You can either point to an external file (through the resource attribute) or define each <property> directly in the xml.

Properties can be referenced elsewhere in the Mybatis config and mapper xml files with ${property} syntax like this (from the documentation):

<properties resource="org/mybatis/example/config.properties"> 
  <property name="username" value="dev_user"/> 
  <property name="password" value="F2Fa3!33TYyg"/> 
</properties> 

<dataSource type="POOLED"> 
  <property name="driver" value="${driver}"/> 
  <property name="url" value="${url}"/> 
  <property name="username" value="${username}"/> 
  <property name="password" value="${password}"/> 
</dataSource> 

Note that property elements override any properties defined in the file.

Answer 2

Because the existing answers were not enough to help me out with the same problem, here is my solution. It works with myBatis 3.2.1.

1. In mybatis-config.xml

• Add those property elements you want to set from inside Java to the <property> section.
• Refer to those elements in the <dataSource> section using ${*property*} as value.

<?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>
        <property name="url" value=""/>
        <property name="username" value=""/>
        <property name="password" value=""/>
    </properties>            
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>  
            <dataSource type="POOLED">
                <property name="url" value="${url}"/>
                <property name="username" value="${username}"/>
                <property name="password" value="${password}"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
    ...
    </mappers>
</configuration>

2. In Java

Create a Properties object, add the properties you selected to set manually and pass it to the build() method when obtaining the SqlSessionFactory:

Properties properties = new Properties();
properties.setProperty("username", "myUser");
properties.setProperty("password", "myPwd");
properties.setProperty("url", "myConnectionURL");

InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream, properties);

Answer 3

Because the existing answers were not enough to help me out with the same problem, here is my solution. It works with myBatis 3.0.3.

mybatis-config.xml file:

<?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>
        <property name="url" value=""/>
        <property name="username" value=""/>
        <property name="password" value=""/>
    </properties>            
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>  
            <dataSource type="POOLED">
                <property name="driver" value="oracle.jdbc.driver.OracleDriver"/>
                <property name="url" value="${url}"/>
                <property name="username" value="${username}"/>
                <property name="password" value="${password}"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
    ...
    </mappers>
</configuration>

Java Code:

Properties properties = new Properties();
properties.setProperty("username", userName);
properties.setProperty("password", password);
properties.setProperty("url", dbURL);

Reader reader = Resources.getResourceAsReader("mybatis-config.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader, properties);

Note: For myBatis 3.0.3, SqlSessionFactoryBuilder().build() method does not take InputStream as a parameter as suggested in answer by user905686, you should use the Reader instead.

Answer 4

If you want to do using Spring 4 and @Configuration in Data Config

How to set fetchSize for iBatis select statement

The difference is the way you can load config file

@Value("classpath:mybatis-config.xml")
private Resource myBatisResource ;

Answer 5

Write yourself datasource which extends form BasicDataSource, as follows.

package org.popkit.mydatasource;

import org.apache.commons.dbcp.BasicDataSource;
import org.apache.commons.lang3.StringUtils;
import org.springframework.beans.factory.InitializingBean;

import java.sql.SQLFeatureNotSupportedException;
import java.util.logging.Logger;

public class MyDataSource extends BasicDataSource implements InitializingBean {

public Logger getParentLogger() throws SQLFeatureNotSupportedException {
    return null;
}

@Override
public void afterPropertiesSet() throws Exception {
    String url = this.getUrl();

    // following do as yourself
    if (StringUtils.isBlank(url)) {
        this.setUrl("#your jdbc.url");
    }
    String username = this.getUsername();
    if (StringUtils.isBlank(username)) {
        this.setUsername("#your jdbc.username");
    }
    String password = this.getPassword();
    if (StringUtils.isBlank(password)) {
        this.setPassword("#your jdbc.pwd");
    }
}

}

in xml

<bean id="dataSource" class="org.popkit.mydatasource.MyDataSource" destroy-method="close">
    <property name="driverClassName" value="com.mysql.jdbc.Driver" />
    <property name="url" value=""/>
    <property name="username" value="" />
    <property name="password" value=""/>
    <property name="initialSize" value="2" />
    <property name="maxActive" value="30" />
    <property name="maxIdle" value="10" />
    <property name="minIdle" value="3" />
    <property name="maxWait" value="30000" />
    <property name="removeAbandoned" value="true" />
    <property name="removeAbandonedTimeout" value="30" />
    <property name="validationQuery" value="SELECT 1" />
</bean>

Answer 6

First write the information regarding driver,username,password in some file and read that file contents in your java application

Properties properties=new Properties();

properties.load("INPUTSTREAM");