Question

IntelliJ IDEA怎么根据数据库表生成实体类

Answer 1

 com.db.gen.entity.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;  
  
public class GenEntityMysql {  
      
    private String packageOutPath = "com.user.entity";//指定实体生成所在包的路径  
    private String authorName = "封狼居胥";//作者名字  
    private String tablename = "user";//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/jbpm";  
    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 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();  
          
    }  
  
}