Properties的load方法的具体使用场景--加载数据库资源

Properties继承了HashTable，HashTable实现了Map

一、Properties继承的源码如下：

 Properties extends Hashtable<Object,Object> public class Hashtable<K,V>    extends Dictionary<K,V>    implements Map<K,V>, Cloneable, java.io.Serializable

二、Properties的load方法的具体使用场景–加载数据库资源

1、DataSourceUtil 代码如下

import java.io.File;import java.io.FileInputStream;import java.io.FilenameFilter;import java.io.InputStreamReader;import java.io.Reader;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;import java.util.Properties;import org.springframework.context.ApplicationContext;import org.springframework.jdbc.core.JdbcTemplate;import com.test.BaseConfigUtil;/** * 加载数据源类，将${catalina.home}/ybg/conf下面的所有数据源文件加入到bean工厂中 */public class DataSourceUtil {    /**     * 初始化     *      * @param applicationContext     */    public static void init(ApplicationContext applicationContext) {            File dataDirectory = new File(System.getProperty("catalina.home") + File.separator + "test" + File.separator + "conf");    // 数据源文件必定要是properties类型。     //过滤的文件名称以db开头，以properties结尾        File[] dataFiles = dataDirectory.listFiles(new FilenameFilter() {            @Override            public boolean accept(File dir, String name) {                String fileName = name.toLowerCase();                if (fileName.endsWith(".properties")) {                    if(fileName.startsWith("db")) {                        return true;                    }                }                return false;            }        });    try (Reader reader = new InputStreamReader(new FileInputStream(dataFiles[i]), "UTF-8")) {                Properties properties = new Properties();                properties.load(reader);//读取数据库的.properties配置文件                if (!properties.isEmpty()) {                    // 建立数据源的bean                    Map<String, Object> propertyMap = new HashMap<String, Object>();                    propertyMap.put("driverClassName", properties.getProperty("sqlDriver"));                    propertyMap.put("url",             properties.getProperty("sqlUrl"));                    propertyMap.put("username",        properties.getProperty("sqlUsername"));                    propertyMap.put("password",        properties.getProperty("sqlPassword"));                    propertyMap.put("initialSize",     properties.getProperty("sqlInitialSize"));                    propertyMap.put("maxTotal",        properties.getProperty("sqlMaxTotal"));                    propertyMap.put("maxIdle",         properties.getProperty("sqlMaxIdle"));                    propertyMap.put("maxWaitMillis",   properties.getProperty("sqlMaxWaitMillis"));                    BeanUtil.addBean( "org.apache.commons.dbcp2.BasicDataSource", name + "_dataSource", propertyMap, null, null, null, "close");                    // 建立jdbcTemplate的bean                    List<String> referenceConstrList = new ArrayList<String>();                    referenceConstrList.add(name + "_dataSource");                    BeanUtil.addBean( "org.springframework.jdbc.core.JdbcTemplate", name + "_jdbcTemplate", null, null, null, referenceConstrList, null);                    LogUtil.info("load datasource file {} success!", dataFiles[i].getAbsolutePath());                }            } catch (Exception e) {                LogUtil.error("load datasource file {} fail!", dataFiles[i].getAbsolutePath());            }        }}    /**     * 获取数据源     * @param datasourceFileName 数据源配置文件名     * @return     */    public static JdbcTemplate getJdbcTemplate(String datasourceFileName) {        String id = datasourceFileName + "_jdbcTemplate";        return BeanUtil.getBean(id, JdbcTemplate.class);    }}

2、BeanUtil代码如下

import java.util.Iterator;import java.util.List;import java.util.Map;import org.springframework.beans.factory.support.BeanDefinitionBuilder;import org.springframework.beans.factory.support.DefaultListableBeanFactory;import org.springframework.context.ApplicationContext;/** * 管理bean类 */public class BeanUtil {    // Spring Bean 工厂    public static DefaultListableBeanFactory beanFactory;    public static void init(ApplicationContext applicationContext) {        beanFactory = (DefaultListableBeanFactory) applicationContext.getAutowireCapableBeanFactory();    }    /**     * 动态增加bean     *      * @param className     * @param beanKey     * @param propertyMap     * @param referenceMap     * @return     */    public static boolean addBean(            String className, String beanKey, Map<String, Object> propertyMap,            Map<String, String> referenceMap, List<Object> propertyConstrList,            List<String> referenceConstrList, String destroyMethod) {        // 判断Spring容器中是否存在该Bean        if (beanFactory.containsBeanDefinition(className)) {            return true;        }        BeanDefinitionBuilder bdb = BeanDefinitionBuilder.rootBeanDefinition(className);        bdb.getBeanDefinition().setAttribute("id", beanKey);        // 设置bean参数属性        if (propertyMap != null && !propertyMap.isEmpty()) {            Iterator<String> propertyKeys = propertyMap.keySet().iterator();            while (propertyKeys.hasNext()) {                String keyString = propertyKeys.next();                bdb.addPropertyValue(keyString, propertyMap.get(keyString));            }        }        // 设置bean参数引用        if (referenceMap != null && !referenceMap.isEmpty()) {            Iterator<String> referenceKeys = referenceMap.keySet().iterator();            while (referenceKeys.hasNext()) {                String keyString = referenceKeys.next();                bdb.addPropertyReference(keyString, referenceMap.get(keyString));            }        }        // 设置bean构造参数属性        if (propertyConstrList != null && !propertyConstrList.isEmpty()) {            for (int i = 0; i < propertyConstrList.size(); i++) {                bdb.addConstructorArgValue(propertyConstrList.get(i));            }        }        // 设置bean构造参数引用        if (referenceConstrList != null && !referenceConstrList.isEmpty()) {            for (int i = 0; i < referenceConstrList.size(); i++) {                bdb.addConstructorArgReference(referenceConstrList.get(i));            }        }        if (destroyMethod != null && !destroyMethod.isEmpty()) {            bdb.setDestroyMethodName(destroyMethod);        }        beanFactory.registerBeanDefinition(beanKey, bdb.getBeanDefinition());        return true;    }    /**     * 获取Bean     *      * @param requiredType     * @return     */    public static <T> T getBean(Class<T> requiredType) {        return beanFactory.getBean(requiredType);    }    /**     * 获取bean     * @param beanName     * @param requiredType     * @return     */    public static <T> T getBean(String beanName,Class<T> requiredType) {        return  beanFactory.getBean(beanName,requiredType);    }}

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