动态创建javabean根据数据库表

根据数据库表来创建javabean，如果数据库表的字段用了下划线的需要自己改下代码，我这里默认就是数据库字段直接是ename这样的。

代码很简单整体如下：

package com.zzg.demo;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;

public class GetJavaBean {
	public static void main(String[] args){
		ArrayList<String> a=new ArrayList<String>();
		a.add("emp");
		a.add("dept");
		HashMap<String,Object>map=new HashMap<String, Object>();
		map.put("driver", "oracle.jdbc.driver.OracleDriver");
		map.put("connectionURL", "jdbc:oracle:thin:@127.0.0.1:1521:orcl");
		map.put("username", "scott");
		map.put("password", "tiger");
		map.put("dir", "D:\\");
		map.put("tablist", a);
		GetJavaBean.getClassBean(map);
    }
	public static void getClassBean(HashMap<String,Object>map){
		getDateSource(map);
	}
	
	
	
	//map中的数据driver,connectionURL，username，password，dir
	
	public static void getDateSource(HashMap<String,Object>map){
		ArrayList<String> tabList = (ArrayList<String>) map.get("tablist");
		Connection con=null;
		Statement st=null;
		ResultSet rs=null;
		try{ 
			Class.forName((String) map.get("driver"));
			con=DriverManager.getConnection((String)map.get("connectionURL"),(String)map.get("username"),(String)map.get("password"));
			st=con.createStatement();
			rs=selectTable2Rs(tabList,st,(String)map.get("dir"));
		}catch(Exception e){e.printStackTrace();
		}finally{
			try{
				rs.close();
			}catch(Exception e){}
			try{
				st.close();
			}catch(Exception e){}
			try{
				con.close();
			}catch(Exception e){}
		}
		
	}
	/**
	 * 
	 * @param tabList 要查询的表的list
	 * @param st 
	 * @param dir  要输出的文件的位置，到文件夹
	 * @return
	 * @throws SQLException
	 * @throws IOException
	 */
	public static ResultSet selectTable2Rs(List<String> tabList,Statement st,String dir) throws SQLException, IOException{
		Iterator<String> iterator=tabList.iterator();
		ResultSet rs=null;
		while(iterator.hasNext()){
			String tabName=iterator.next();
			String sql="select * from "+tabName;
				rs=st.executeQuery(sql);
				operateTable(rs,tabName,dir);
		}
		return rs;
		
	}
	/**
	 * 挖取数据
	 * @param rs
	 * @param tabName 要查询的数据库表的名字
	 * @param dir 要输出的文件的位置，到文件夹
	 * @throws SQLException
	 * @throws IOException
	 */
	public static void operateTable(ResultSet rs,String tabName,String dir) throws SQLException, IOException{
		ResultSetMetaData rsmd = rs.getMetaData();  
		int colsLength = rsmd.getColumnCount(); 
		List<String> colTypes = new ArrayList<String>(); 
		List<String> colNames = new ArrayList<String>(); 
		for(int i=0;i<colsLength;i++){
			String name=rsmd.getColumnName(i+1);
			String type=rsmd.getColumnClassName(i+1);
			colNames.add(i, name.toLowerCase());
			colTypes.add(i,type);
		}
		output2JavaFile(colNames,colTypes,tabName,dir);
		
	}
	public static void output2JavaFile(List<String> colNames,List<String> colTypes,String tabName,String dir) throws IOException{
		String fileStream=outputStream(colNames, colTypes, tabName);
		String dirFile=dir+getClassName(tabName)+".java";
		File file = new File(dirFile);
		if(file.exists()){
			System.out.println("警告：<"+dirFile+"存在无法创建，请先删除"+getClassName(tabName)+".java"+"旧的文件>");
		}else{
			BufferedWriter writer = new BufferedWriter(new FileWriter(dirFile));  
			writer.write(fileStream.toString());
			writer.flush();
			//关闭资源  
			writer.close();
			System.out.println("文件"+getClassName(tabName)+".java"+"写入成功");
		}
		
	};
	public static String outputStream(List<String> colNames,List<String> colTypes,String tabName){
		tabName=getClassName(tabName);
		StringBuilder sb=new StringBuilder();
		sb.append("public class "+tabName+"{\n");
		sb.append(getClassStream(colNames,colTypes));
		sb.append("public ").append(tabName).append("(){}").append("\n");
		sb.append(outputMethod(colNames, colTypes));
		sb.append("\n}");
		//System.out.println(sb.toString());
		return sb.toString();
	}
	
	public static String getClassStream(List<String> colNames,List<String> colTypes){
		StringBuilder sb=new StringBuilder();
		for(int i=0;i<colNames.size();i++){
			sb.append("private ");
			sb.append(colTypes.get(i)+" "+colNames.get(i));
			sb.append(";\n");
		}
		return sb.toString();
	}
	
	
	
	public static String outputMethod(List<String> colNames,List<String> colTypes){
		StringBuilder sb=new StringBuilder();
		for(int i=0;i<colNames.size();i++){
			sb.append("\n");
			sb.append(getMethod(colNames.get(i),colTypes.get(i)));
			sb.append("\n");
			sb.append(setMethod(colNames.get(i)));
		}
		return sb.toString();
		
	}
	
	public static String getMethod(String name,String type){
		StringBuilder sb=new StringBuilder();
		
		sb.append("public ").append(type).append(" get");
		sb.append(name.substring(0,1).toUpperCase()+name.substring(1,name.length()));
		sb.append("(){").append("\n");
		sb.append(" return ").append(name).append(";").append("\n");
		sb.append("}").append("\n");
		return sb.toString();
	}
	public static String setMethod(String name){
		StringBuilder sb=new StringBuilder();
		sb.append("public void ").append("set");
		sb.append(name.substring(0,1).toUpperCase()+name.substring(1,name.length()));
		sb.append("(){").append("\n");
		sb.append(" this. ").append(name).append("=").append(name).append(";").append("\n");
		sb.append("}").append("\n");
		return sb.toString();
	}
	public static String getClassName(String tabName){
		return tabName.toLowerCase().substring(0,1).toUpperCase()+
				tabName.toLowerCase().substring(1,tabName.length());
	}
}

后面我会对类型进行改进，一般大家用比较多的一般是int，String,Date这样。但是现在用的是java.sql.*的。