java 工具篇（MySQL数据库工具）数据库实体创建

小鱼儿 2023-10-16 20:21 1阅读 0赞

第一步：生成工具源代码：

package com.mysql.util;
    
    
    
    
    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.ResultSet;
    import java.sql.ResultSetMetaData;
    import java.sql.SQLException;
    import java.sql.Statement;
    import java.util.Date;
    
    
    
    public class GenEntityMysql {
    	private String packageOutPath = "com.itaas.entity";// 指定实体生成所在包的路径
    	private String authorName = "周志刚";// 作者名字
    	private String tablename = "TB_SW_BLADE_COLL";// 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://192.168.0.32:3306/ITaa?useUnicode=true&characterEncoding=utf-8";
    	private static final String NAME = "root";
    	private static final String PASS = "Vixuan724";
    	private static final String DRIVER = "com.mysql.jdbc.Driver";
    	
    	/* 
    	     * 构造函数 
    	     */  
    	   public GenEntityMysql(){  
    	       //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()); 
    	              //获取当前项目路径
    	               String path=this.getClass().getResource("").getPath();  
    	                
    	               System.out.println(path);  
                  System.out.println("src/?/"+path.substring(path.lastIndexOf("/com/", path.length())) );  
    	 
    	                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 (IOException e) {  
    	                e.printStackTrace();  
    	          }  
    	             
    	        } catch (SQLException e) {  
    	           e.printStackTrace();  
    	       } finally{  
    	
    	        }  
    	    } 
    	   
    	   /** 
    	      * 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("    * "+tablename+" 实体类\r\n");  
    	        sb.append("    * "+new Date()+" "+this.authorName+"\r\n");  
    	         sb.append("    */ \r\n");  
    	         //实体部分  
    	         sb.append("\r\n\r\npublic class " + initcap(tablename) + "{\r\n");  
    	         processAllAttrs(sb);//属性  
    	          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 "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;  
    	     }  
    	      
    	     public static void main(String[] arg){
    	    	 new GenEntityMysql();  
    	     }
    	   
    	   
    
    }

项目结构图：

![Center][]

[Center]: https://img-blog.csdn.net/20140807131820281?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvemhvdXpoaXdlbmdhbmc=/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center