快速开发 生成实体类(一)

首先将连接各种数据库的jar包放进项目中


一 Mysql数据库连接类
package cn.jbit.entity;

import java.io.File;
import java.io.FileWriter;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.text.SimpleDateFormat;

public class GenEntityMysql {

private String packageOutPath = "cn.jbit.entity";//指定实体生成所在包的路径  private String authorName = "任锯东";//作者名字  private String tablename = "book";//数据库表名  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.*  //Mysql数据库连接private static final String driver = "com.mysql.jdbc.Driver";// 数据库驱动字符串private static final String url = "jdbc:mysql://localhost:3306/struts2?useUnicode=true&characterEncoding=utf8";// 连接URL字符串 student指mysql里新建数据库名private static final String user = "root";// 数据库用户名private static final String password = "root";// 用户密码private Connection conn=null;private PreparedStatement pstmt=null;private ResultSet rs=null;//创建数据库连接public Connection getConnection(){    try {        Class.forName(driver);        conn = DriverManager.getConnection(url, user, password);    } catch (Exception e) {        // TODO Auto-generated catch block        System.out.println(e.getMessage());        e.printStackTrace();    }    return conn;}//关闭数据库连接public void closeAll(ResultSet rs,PreparedStatement pstmt,Connection conn){    try {        if(rs!=null){            rs.close();        }        if(pstmt!=null){            pstmt.close();        }        if(conn!=null){            conn.close();        }    } catch (Exception e) {        // TODO Auto-generated catch block        System.out.println(e.getMessage());        e.printStackTrace();    }}/*  * 构造函数  */  public GenEntityMysql(){    try {         //打开数据库连接         conn = getConnection();        String sql = "select * from " + tablename;          pstmt = conn.prepareStatement(sql);          rs = pstmt.executeQuery();        ResultSetMetaData rsmd = rs.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("/cn/", path.length())) );              // String outputPath = directory.getAbsolutePath()+ "/src/"+path.substring(path.lastIndexOf("/com/", path.length()), path.length()) + initcap(tablename) + ".java";              String outputPath = directory.getAbsolutePath()+ "/src/"+this.packageOutPath.replace(".", "/")+"/"+initcap(tablename) + ".java";              FileWriter fw = new FileWriter(outputPath);              PrintWriter pw = new PrintWriter(fw);              pw.println(content);              pw.flush();              pw.close();          } catch (Exception e) {              // TODO Auto-generated catch block            System.out.println(e.getMessage());            e.printStackTrace();          }      } catch (Exception e) {          // TODO Auto-generated catch block        System.out.println(e.getMessage());        e.printStackTrace();      } finally{          closeAll(rs, pstmt, conn);//关闭数据库连接     }  }  /**  * 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;\r\n");      }      if(f_sql){          sb.append("import java.sql.*;\r\n");      }      sb.append("package " + this.packageOutPath + ";\r\n");      sb.append("\r\n");      //注释部分    sb.append("/**\r\n");    sb.append(" * "+"@author "+this.authorName+"  "+initcap(tablename)+"实体(Entity)类\r\n");    sb.append(" * "+"@date "+new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(System.currentTimeMillis())+"\r\n");    sb.append(" */");    //实体部分    sb.append("\r\npublic class " + initcap(tablename) + "{\r\n");    sb.append("\r\n");    processAllAttrs(sb);//属性    sb.append("\r\n");    processAllMethod(sb);//get set方法    sb.append("}\r\n");    //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] + ";\r\n");      }  }  /**  * 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] + "){\r\n");          sb.append("\tthis." + colnames[i] + "=" + colnames[i] + ";\r\n");          sb.append("\t}\r\n");          sb.append("\tpublic " + sqlType2JavaType(colTypes[i]) + " get" + initcap(colnames[i]) + "(){\r\n");          sb.append("\t\treturn " + colnames[i] + ";\r\n");          sb.append("\t}\r\n");      }  }  /**  * 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 "Integer";      }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 "String";  }  /**  * 出口  * TODO  * @param args  */  public static void main(String[] args) {    // TODO Auto-generated method stub    long startTime = System.currentTimeMillis();//开始时间  返回以毫秒为单位的当前时间。注意，当返回值的时间单位是毫秒时，值的粒度取决于底层操作系统，并且粒度可能更大。    System.out.println("------->>>开始时间:"+new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(startTime));    new GenEntityMysql();      long endTime = System.currentTimeMillis();//结束时间    System.out.println("------->>>结束时间:"+new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(startTime));    long execTime=endTime-startTime;    System.out.println("------->>>所用时间:"+execTime+" ms");}  

}
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