JAVA 数据表反射实体类，自动生成实体类

Dear 丶 2022-05-23 06:59 277阅读 0赞

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;  
    
    public class GenEntityMysql {   
    
        private String packageOutPath = "com.yunti.entity";//指定实体生成所在包的路径 
        private String authorName = "Nmggy";//作者名字 
        private String tablename = "sponsor";//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/network";  
        private static final String NAME = "root";  
        private static final String PASS = "";  
        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()); 
                    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/"+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 (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;\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;  
        }  
    
        /** * 出口 * TODO * @param args */  
        public static void main(String[] args) {  
    
            new GenEntityMysql();  
    
        }  
    
    }