从数据库表反射出实体类，自动生成实体类

package com.share.barter.tool;

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.Date;

/**
 * POJO Product
 * @author  Tumi
 * 日期：2012-10-10
 */
public class GenEntity {
 
 private String tablename = "Business_has_Barter";//表名
 private String[] colnames; // 列名数组
 private String[] colTypes; //列名类型数组
 private int[] colSizes; //列名大小数组
 private boolean f_util = false; // 是否需要导入包java.util.*
 private boolean f_sql = false; // 是否需要导入包java.sql.*
   
    //数据库连接
  private static final String URL ="jdbc:mysql://localhost:3306/barter";
  private static final String NAME = "root";
  private static final String PASS = "root";
  private static final String DRIVER ="com.mysql.jdbc.Driver";

 /*
  * 构造函数
  */
 public GenEntity(){
     //创建连接
     Connection con;
  //查要生成实体类的表
     String sql = "select * from " + tablename;
     PreparedStatement pStemt = null;
     try {
      try {
    Class.forName(DRIVER);
   } catch (ClassNotFoundException e1) {
    // TODO Auto-generated catch block
    e1.printStackTrace();
   }
      con = DriverManager.getConnection(URL,NAME,PASS);
   pStemt = con.prepareStatement(sql);
   ResultSetMetaData rsmd = pStemt.getMetaData();
   int size = rsmd.getColumnCount(); //统计列
   colnames = new String[size];
   colTypes = new String[size];
   colSizes = new int[size];
   for (int i = 0; i < size; i++) {
    colnames[i] = rsmd.getColumnName(i + 1);
    colTypes[i] = rsmd.getColumnTypeName(i + 1);
    
    if(colTypes[i].equalsIgnoreCase("datetime")){
     f_util = true;
    }
    if(colTypes[i].equalsIgnoreCase("image") || colTypes[i].equalsIgnoreCase("text")){
     f_sql = true;
    }
    colSizes[i] = rsmd.getColumnDisplaySize(i + 1);
   }
   
   String content = parse(colnames,colTypes,colSizes);
   
   try {
    File directory = new File("");
    //System.out.println("绝对路径："+directory.getAbsolutePath());
    //System.out.println("相对路径："+directory.getCanonicalPath());
    String path=this.getClass().getResource("").getPath();
    
    System.out.println(path);
    System.out.println("src/?/"+path.substring(path.lastIndexOf("/com/", path.length())) );
    FileWriter fw = new FileWriter(directory.getAbsolutePath()+ "/src/"+path.substring(path.lastIndexOf("/com/", path.length()), path.length()) + initcap(tablename) + ".java");
    PrintWriter pw = new PrintWriter(fw);
    pw.println(content);
    pw.flush();
    pw.close();
   } catch (IOException e) {
    e.printStackTrace();
   }
   
  } catch (SQLException e) {
   e.printStackTrace();
  } finally{
//   try {
//    con.close();
//   } catch (SQLException e) {
//    // TODO Auto-generated catch block
//    e.printStackTrace();
//   }
  }
    }

 /**
  * 功能：生成实体类主体代码
  * @param colnames
  * @param colTypes
  * @param colSizes
  * @return
  */
 private String parse(String[] colnames, String[] colTypes, int[] colSizes) {
  StringBuffer sb = new StringBuffer();
  
  //判断是否导入工具包
  if(f_util){
   sb.append("import java.util.Date;rn");
  }
  if(f_sql){
   sb.append("import java.sql.*;rn");
  }
  sb.append("package com.share.barter.tool;rn");
  sb.append("rn");
  //注释部分
  sb.append("   /**rn");
  sb.append("    * "+tablename+" 实体类rn");
  sb.append("    * "+new Date()+"  Ze Mingrn");
  sb.append("    */ rn");
  //实体部分
  sb.append("rnrnpublic class " + initcap(tablename) + "{rn");
  processAllAttrs(sb);//属性
  processAllMethod(sb);//get set方法
  sb.append("}rn");
  
     //System.out.println(sb.toString());
  return sb.toString();
 }
 
 /**
  * 功能：生成所有属性
  * @param sb
  */
 private void processAllAttrs(StringBuffer sb) {
  
  for (int i = 0; i < colnames.length; i++) {
   sb.append("tprivate " + sqlType2JavaType(colTypes[i]) + " " + colnames[i] + ";rn");
  }
  
 }

 /**
  * 功能：生成所有方法
  * @param sb
  */
 private void processAllMethod(StringBuffer sb) {
  
  for (int i = 0; i < colnames.length; i++) {
   sb.append("tpublic void set" + initcap(colnames[i]) + "(" + sqlType2JavaType(colTypes[i]) + " " +
     colnames[i] + "){rn");
   sb.append("tthis." + colnames[i] + "=" + colnames[i] + ";rn");
   sb.append("t}rn");
   sb.append("tpublic " + sqlType2JavaType(colTypes[i]) + " get" + initcap(colnames[i]) + "(){rn");
   sb.append("ttreturn " + colnames[i] + ";rn");
   sb.append("t}rn");
  }
  
 }
 
 /**
  * 功能：将输入字符串的首字母改成大写
  * @param str
  * @return
  */
 private String initcap(String str) {
  
  char[] ch = str.toCharArray();
  if(ch[0] >= 'a' && ch[0] <= 'z'){
   ch[0] = (char)(ch[0] - 32);
  }
  
  return new String(ch);
 }

 /**
  * 功能：获得列的数据类型
  * @param sqlType
  * @return
  */
 private String sqlType2JavaType(String sqlType) {
  
  if(sqlType.equalsIgnoreCase("bit")){
   return "boolean";
  }else if(sqlType.equalsIgnoreCase("tinyint")){
   return "byte";
  }else if(sqlType.equalsIgnoreCase("smallint")){
   return "short";
  }else if(sqlType.equalsIgnoreCase("int")){
   return "int";
  }else if(sqlType.equalsIgnoreCase("bigint")){
   return "long";
  }else if(sqlType.equalsIgnoreCase("float")){
   return "float";
  }else if(sqlType.equalsIgnoreCase("decimal") || sqlType.equalsIgnoreCase("numeric")
    || sqlType.equalsIgnoreCase("real") || sqlType.equalsIgnoreCase("money")
    || sqlType.equalsIgnoreCase("smallmoney")){
   return "double";
  }else if(sqlType.equalsIgnoreCase("varchar") || sqlType.equalsIgnoreCase("char")
    || sqlType.equalsIgnoreCase("nvarchar") || sqlType.equalsIgnoreCase("nchar")
    || sqlType.equalsIgnoreCase("text")){
   return "String";
  }else if(sqlType.equalsIgnoreCase("datetime")){
   return "Date";
  }else if(sqlType.equalsIgnoreCase("image")){
   return "Blod";
  }
  
  return null;
 }
 
 /**
  * 出口
  * TODO
  * @param args
  */
 public static void main(String[] args) {
  
  new GenEntity();
  
 }

}

package com.share.barter.tool;import java.io.File;import java.io.FileWriter;import java.io.IOException;import java.io.PrintWriter;import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.ResultSetMetaData;import java.sql.SQLException;import java.util.Date;/** * POJO Product * @author Tumi * 日期：2012-10-10*/public class GenEntity {private String tablename ="Business_has_Barter";//表名private String[] colnames; // 列名数组private String[] colTypes; //列名类型数组private int[] colSizes; //列名大小数组private boolean f_util = false; // 是否需要导入包java.util.*private boolean f_sql = false; // 是否需要导入包java.sql.*//数据库连接 private static final String URL ="jdbc:mysql://localhost:3306/barter"; private static final String NAME ="root"; private static final String PASS ="root"; private static final String DRIVER ="com.mysql.jdbc.Driver";/* * 构造函数*/public GenEntity(){//创建连接 Connection con;//查要生成实体类的表 String sql ="select * from"+ tablename; PreparedStatement pStemt = null; try { try {Class.forName(DRIVER);} catch (ClassNotFoundException e1) {// TODO Auto-generated catch blocke1.printStackTrace();} con = DriverManager.getConnection(URL,NAME,PASS);pStemt = con.prepareStatement(sql);ResultSetMetaData rsmd = pStemt.getMetaData();int size = rsmd.getColumnCount();//统计列colnames = new String[size];colTypes = new String[size];colSizes = new int[size];for (int i = 0; i < size; i++) {colnames[i] = rsmd.getColumnName(i + 1);colTypes[i] = rsmd.getColumnTypeName(i + 1);if(colTypes[i].equalsIgnoreCase("datetime")){f_util = true;}if(colTypes[i].equalsIgnoreCase("image") || colTypes[i].equalsIgnoreCase("text")){f_sql = true;}colSizes[i] = rsmd.getColumnDisplaySize(i + 1);}String content = parse(colnames,colTypes,colSizes);try {File directory = new File("");//System.out.println("绝对路径："+directory.getAbsolutePath());//System.out.println("相对路径："+directory.getCanonicalPath());String path=this.getClass().getResource("").getPath();System.out.println(path);System.out.println("src/?/"+path.substring(path.lastIndexOf("/com/", path.length())) );FileWriter fw = new FileWriter(directory.getAbsolutePath()+"/src/"+path.substring(path.lastIndexOf("/com/", path.length()), path.length()) + initcap(tablename) +".java");PrintWriter pw = new PrintWriter(fw);pw.println(content);pw.flush();pw.close();} catch (IOException e) {e.printStackTrace();}} catch (SQLException e) {e.printStackTrace();} finally{//try {//con.close();//} catch (SQLException e) {//// TODO Auto-generated catch block//e.printStackTrace();//}}}/** * 功能：生成实体类主体代码 * @param colnames * @param colTypes * @param colSizes * @return*/private String parse(String[] colnames, String[] colTypes, int[] colSizes) {StringBuffer sb = new StringBuffer();//判断是否导入工具包if(f_util){sb.append("import java.util.Date;rn");}if(f_sql){sb.append("import java.sql.*;rn");}sb.append("package com.share.barter.tool;rn");sb.append("rn");//注释部分sb.append("/**rn");sb.append("*"+tablename+"实体类rn");sb.append("*"+new Date()+"Ze Mingrn");sb.append("*/ rn");//实体部分sb.append("rnrnpublic class"+ initcap(tablename) +"{rn");processAllAttrs(sb);//属性processAllMethod(sb);//get set方法sb.append("}rn");//System.out.println(sb.toString());return sb.toString();}/** * 功能：生成所有属性 * @param sb*/private void processAllAttrs(StringBuffer sb) {for (int i = 0; i < colnames.length; i++) {sb.append("tprivate"+ sqlType2JavaType(colTypes[i]) +""+ colnames[i] +";rn");}}/** * 功能：生成所有方法 * @param sb*/private void processAllMethod(StringBuffer sb) {for (int i = 0; i < colnames.length; i++) {sb.append("tpublic void set"+ initcap(colnames[i]) +"("+ sqlType2JavaType(colTypes[i]) +""+ colnames[i] +"){rn");sb.append("tthis."+ colnames[i] +"="+ colnames[i] +";rn");sb.append("t}rn");sb.append("tpublic"+ sqlType2JavaType(colTypes[i]) +"get"+ initcap(colnames[i]) +"(){rn");sb.append("ttreturn"+ colnames[i] +";rn");sb.append("t}rn");}}/** * 功能：将输入字符串的首字母改成大写 * @param str * @return*/private String initcap(String str) {char[] ch = str.toCharArray();if(ch[0] >= 'a' && ch[0] <= 'z'){ch[0] = (char)(ch[0] - 32);}return new String(ch);}/** * 功能：获得列的数据类型 * @param sqlType * @return*/private String sqlType2JavaType(String sqlType) {if(sqlType.equalsIgnoreCase("bit")){return"boolean";}else if(sqlType.equalsIgnoreCase("tinyint")){return"byte";}else if(sqlType.equalsIgnoreCase("smallint")){return"short";}else if(sqlType.equalsIgnoreCase("int")){return"int";}else if(sqlType.equalsIgnoreCase("bigint")){return"long";}else if(sqlType.equalsIgnoreCase("float")){return"float";}else if(sqlType.equalsIgnoreCase("decimal") || sqlType.equalsIgnoreCase("numeric") || sqlType.equalsIgnoreCase("real") || sqlType.equalsIgnoreCase("money") || sqlType.equalsIgnoreCase("smallmoney")){return"double";}else if(sqlType.equalsIgnoreCase("varchar") || sqlType.equalsIgnoreCase("char") || sqlType.equalsIgnoreCase("nvarchar") || sqlType.equalsIgnoreCase("nchar") || sqlType.equalsIgnoreCase("text")){return"String";}else if(sqlType.equalsIgnoreCase("datetime")){return"Date";}else if(sqlType.equalsIgnoreCase("image")){return"Blod";}return null;}/** * 出口 * TODO * @param args*/public static void main(String[] args) {new GenEntity();}}

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