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java从数据库映射实体类的代码

java从数据库映射实体类的代码

作者: 22334 | 来源:发表于2021-11-17 15:54 被阅读0次

如下的内容内容是关于java从数据库映射实体类的内容。

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;

public class GenEntity {

private static final String NAME = "root";

private static final String PASS = "root";

private static final String DRIVER ="com.mysql.jdbc.Driver";

public GenEntity(){

    Connection con;

    PreparedStatement pStemt = null;

    try {

    try {

Class.forName(DRIVER);

} catch (ClassNotFoundException e1) {

e1.printStackTrace();

}

    con = DriverManager.getConnection(URL,NAME,PASS);

pStemt = con.prepareStatement(sql);

ResultSetMetaData rsmd = pStemt.getMetaData();

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("");

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{

}

    }

private String parse(String[] colnames, String[] colTypes, int[] colSizes) {

StringBuffer sb = new StringBuffer();

if(f_util){

sb.append("import java.util.Date;rn");

}

if(f_sql){

}

sb.append("package com.share.barter.tool;rn");

sb.append("rn");

sb.append("rnrnpublic class " + initcap(tablename) + "{rn");

sb.append("}rn");

return sb.toString();

}

private void processAllAttrs(StringBuffer sb) {

for (int i = 0; i < colnames.length; i++) {

sb.append("tprivate " + sqlType2JavaType(colTypes[i]) + " " + colnames[i] + ";rn");

}

}

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");

}

}

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);

}

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[] args) {

new GenEntity();

}

}

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