JFinal 表自動綁定插件實現，實現零配置，支持多數據源

以mysql數據庫實現爲例，其它的db也可基於這種方式自己實現

大概的思路是這樣的，爲了簡少配置，所以不使用註解的方式

首先需要一個工具類來拿到所有的Model類大體的實現方式如下

package com.nmtx.utils;

import java.io.File;
import java.util.ArrayList;
import java.util.List;

import com.jfinal.kit.PathKit;
import com.jfinal.kit.StrKit;

public class ClassUtils {
    public static String classRootPath = null;

    public static List<Class<?>> scanPackage(String packageName) throws ClassNotFoundException {
        List<Class<?>> classList = new ArrayList<Class<?>>();
        String path = getClassRootPath() + "/" + packageName.replace(".", "/");
        List<String> fileNameList = getAllFileName(path);
        for (String fileName : fileNameList) {
            classList.add(Class.forName(fileName));
        }
        return classList;
    }

    public static List<String> getAllFileName(String path) {
        List<String> fileNameList = new ArrayList<String>();
        File rootFile = new File(path);
        if (rootFile.isFile()) {
            String fileName = rootFile.getPath().replace(PathKit.getRootClassPath(), "").replace(File.separator, ".")
                    .replaceFirst(".", "");
            String prefix = fileName.substring(fileName.lastIndexOf(".") + 1);
            if (prefix.equals("class")) {
                fileNameList.add(fileName.substring(0, fileName.lastIndexOf(".")));
            }
        } else {
            File[] files = rootFile.listFiles();
            if (files != null) {
                for (File file : files) {
                    fileNameList.addAll(getAllFileName(file.getPath()));
                }
            }
        }
        return fileNameList;
    }

    public static String getClassRootPath() {
        if (StrKit.isBlank(classRootPath))
            classRootPath = PathKit.getRootClassPath();
        return classRootPath;
    }

    public static void setClassRootPath(String classRootPath) {
        ClassUtils.classRootPath = classRootPath;
    }
}

有了工具類，就去處理自動掃描插件，大概實現是這樣的

package com.nmtx.plugins.db;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import com.jfinal.kit.StrKit;
import com.jfinal.plugin.IPlugin;
import com.jfinal.plugin.activerecord.ActiveRecordPlugin;
import com.jfinal.plugin.activerecord.Model;
import com.jfinal.plugin.c3p0.C3p0Plugin;
import com.nmtx.plugins.db.impl.TableToModelByUnderline;
import com.nmtx.utils.ClassUtils;

public class AutoTabelPlugin implements IPlugin {
    private String db;
    private ActiveRecordPlugin arp;
    private String pacekageName;
    private String idKey;
    private ITableToModelFormat tableToModelFormate;
    private C3p0Plugin c3p0Plugin;

    public AutoTabelPlugin(C3p0Plugin erpC3p0, ActiveRecordPlugin arp, String db, String packageName, String idKey,
            ITableToModelFormat tableToModelFormate) {
        this.db = db;
        this.arp = arp;
        this.idKey = idKey;
        this.tableToModelFormate = tableToModelFormate;
        this.c3p0Plugin = erpC3p0;
    }

    public AutoTabelPlugin(C3p0Plugin erpC3p0, ActiveRecordPlugin arp, String db, String packageName, String idKey) {
        this.db = db;
        this.arp = arp;
        this.idKey = idKey;
        this.pacekageName = packageName;
        this.tableToModelFormate = new TableToModelByUnderline();
        this.c3p0Plugin = erpC3p0;
    }

    @SuppressWarnings({ "unchecked" })
    public List<Class<? extends Model<?>>> getModelClass() throws ClassNotFoundException {
        List<Class<?>> classes = ClassUtils.scanPackage(pacekageName);
        List<Class<? extends Model<?>>> modelClasses = new ArrayList<Class<? extends Model<?>>>();
        for (Class<?> classer : classes) {
            modelClasses.add((Class<? extends Model<?>>) classer);
        }
        return modelClasses;
    }

    public boolean start() {
        try {
            HashMap<String, String> tableMap = getTableMap();
            List<Class<? extends Model<?>>> modelClasses = getModelClass();
            for (Class<? extends Model<?>> modelClass : modelClasses) {
                String tableName = tableMap.get(modelClass.getSimpleName());
                if (tableName != null) {
                    if (StrKit.notBlank(idKey)) {
                        arp.addMapping(tableName, idKey, modelClass);
                    } else {
                        arp.addMapping(tableName, modelClass);
                    }

                }
            }
        } catch (ClassNotFoundException e) {
            throw new RuntimeException("auto table mappming is exception" + e);
        }

        return true;
    }

    /**
     * 獲取Model和表名的映射
     * 
     * @return
     */
    private HashMap<String, String> getTableMap() {
        HashMap<String, String> map = new HashMap<String, String>();
        Connection connection = null;
        PreparedStatement preStatement = null;
        ResultSet resultSet = null;
        try {
            c3p0Plugin.start();
            connection = c3p0Plugin.getDataSource().getConnection();
            preStatement = connection.prepareStatement(
                    "select table_name as tableName from information_schema.tables where table_schema='" + db
                            + "' and table_type='base table'");
            resultSet = preStatement.executeQuery();
            while (resultSet.next()) {
                String tableName = resultSet.getString(1);
                map.put(tableToModelFormate.getTableByModel(tableName), tableName);
            }
        } catch (Exception e) {
            closeConnection(connection, preStatement, resultSet);
            throw new RuntimeException("auto table mappming is exception" + e);
        } finally {
            closeConnection(connection, preStatement, resultSet);
        }
        return map;

    }

    private void closeConnection(Connection connection, PreparedStatement preStatement, ResultSet resultSet) {
        try {
            if (resultSet != null) {
                resultSet.close();
            }
            if (preStatement != null) {
                preStatement.close();
            }
            if (connection != null) {
                connection.close();
            }
        } catch (SQLException e) {
            throw new RuntimeException("auto close db connection  is exception" + e);
        }
    }

    public boolean stop() {
        return true;
    }

}

因爲java裏的屬性一般都是駝峯規則，代碼看起來舒服一點，這裏以數據庫中以大寫字母爲例,表名爲T_USER,對應Model名爲User實現如下

接口定義

package com.nmtx.plugins.db;

public interface ITableToModelFormat {
   public String generateTableNameToModelName(String tableName);
}

實現如下

package com.nmtx.plugins.db.impl;

import com.nmtx.plugins.db.ITableToModelFormat;

public class TableToModelByUnderline implements ITableToModelFormat{

    public String generateTableNameToModelName(String tableName) {
        StringBuilder modelName = new StringBuilder();
        tableName = tableName.substring(2).toLowerCase();
        String tableNames[] = tableName.split("_");
        for(String tableNameTemp:tableNames){
            modelName.append(fisrtStringToUpper(tableNameTemp));
        }
        return modelName.toString();
    }
    
    private String fisrtStringToUpper(String string){
        return string.replaceFirst(string.substring(0, 1),string.substring(0, 1).toUpperCase()); 
    }
    
}

如果不同的格式可以實現不同的方法，根據自己的需求，這樣就完成了自動掃描插件，使用起來也方便如下

C3p0Plugin spuC3p0= new C3p0Plugin(getProperty("jdbc.mysql.url"),
                getProperty("jdbc.mysql.username").trim(), getProperty("jdbc.mysql.password").trim(),
                getProperty("jdbc.mysql.driverClass"));
        spuC3p0.setMaxPoolSize(Integer.parseInt(getProperty("jdbc.mysql.maxPool")));
        spuC3p0.setMinPoolSize(Integer.parseInt(getProperty("jdbc.mysql.minPool")));
        spuC3p0.setInitialPoolSize(Integer.parseInt(getProperty("jdbc.mysql.initialPoolSize")));
        ActiveRecordPlugin spuArp = new ActiveRecordPlugin(DbConfigName.SPU, spuC3p0);
        AutoTabelPlugin spuAutoTabelPlugin = new AutoTabelPlugin(spuC3p0, spuArp, getProperty("jdbc.mysql.spu.db"),
                "com.nmtx.manager.model", "ID");
        me.add(spuAutoTabelPlugin);
        me.add(spuArp);

如果有多個就可以配置多個插件，而無需在管映射了，新增Model直接新增即可，不要再管映射