Mysql映射java实体类

package com.utils.database; import java.io.*; import java.sql.*; import java.util.*; /** * * @author 聂长安 * */ public class CreatEntity { private static final String driver = "com.mysql.jdbc.Driver"; private static final String url = "jdbc:mysql://127.0.0.1:3306/petshop?useUnicode=true&amp;characterEncoding=UTF-8"; private static final String user = "niechangan"; private static final String pwd = "root"; private static String PACKAGENAME = "com.changan.entity"; private static Connection conn = null; private CreatEntity(){} public static Connection getConnection() throws ClassNotFoundException, SQLException{ if(conn == null){ Class.forName(driver); conn = DriverManager.getConnection(url, user, pwd); System.out.println("数据库连接已建立"); } return conn; } public static void query(String sql) throws ClassNotFoundException, SQLException{ conn = getConnection(); PreparedStatement ps = conn.prepareStatement(sql); ResultSet rs = ps.executeQuery(); while (rs.next()) { System.out.println(rs.getString(1)); } } public static List<Object> getAllTableName() throws ClassNotFoundException, SQLException{ conn = getConnection(); List<Object> tables = new ArrayList<Object>(); DatabaseMetaData metaData = conn.getMetaData(); String [] types = {"TABLE"}; ResultSet rs = metaData.getTables(null, null, null, types); while (rs.next()) { tables.add(rs.getObject("TABLE_NAME")); } return tables; } public static List<Column> getColumnFromTable(String tableName) throws ClassNotFoundException, SQLException{ conn = getConnection(); ResultSet rs = conn.getMetaData().getColumns(null, "%", tableName, "%"); List<Column> result = new ArrayList<Column>(); while(rs.next()){ Column c = new Column(); c.setName(rs.getString("COLUMN_NAME")); c.setType(rs.getString("TYPE_NAME")); c.setAutoincrement(rs.getString("IS_AUTOINCREMENT").equals("YES") ? true : false); c.setRemark(rs.getString("REMARKS")); result.add(c); } return result; } public static void writeFile(String str, String destPath) throws IOException{ FileOutputStream out = null; out = new FileOutputStream(new File(destPath),true); out.write(str.getBytes("UTF-8")); out.close(); } public static String getColumnTypeRelation(String type){ if (ColumnType.BIGINT.equals(type)) { return DataType.LONG; }else if(ColumnType.DOUBLE.equals(type)){ return DataType.DOUBLE; }else if(ColumnType.DATETIME.equals(type)){ return DataType.DATETIME; }else if(ColumnType.INT.equals(type)){ return DataType.INTEGER; }else if(ColumnType.SMALLINT.equals(type)){ return DataType.INTEGER; }else if(ColumnType.VARCHAR.equals(type)){ return DataType.STRING; }else if(ColumnType.CHAR.equals(type)){ return DataType.CHAR; }else if(ColumnType.TIMESTAMP.equals(type)){ return DataType.TIMESTAMP; } return null; } /** * 自动将数据库中的实体类映射成Entity * @param packageName 包名 * @param tableName 表名 * @param useAnnotation 是否启用注解 * @param destPath 目标路径 * @throws ClassNotFoundException * @throws SQLException * @throws IOException */ public static void createEneityClass(String packageName, String tableName, boolean useAnnotation, String destPath) throws ClassNotFoundException, SQLException, IOException{ List<Column> columns = getColumnFromTable(tableName); StringBuilder sb = new StringBuilder(); //包名 sb.append("package " + packageName + ";\n\n"); //导包 sb.append("import java.util.Date;\n\n"); /*if (useAnnotation) { sb.append("import javax.persistence.*;\n\n"); }*/ //创建class /*if (useAnnotation) { sb.append("@Entity\n"); sb.append("@Table(name = \"" + tableName.toUpperCase() + "\")\n"); }*/ String formatTblName = formatName(tableName, true); sb.append("public class " + formatTblName + "{\n"); writeFile(sb.toString(), destPath); for (Column c : columns) { String dataType = getColumnTypeRelation(c.getType()); String remark = c.getRemark(); String columnName = c.getName(); String name = formatName(c.getName(), false); String upperName = formatName(c.getName(), true); boolean isAutoincrement = c.isAutoincrement(); sb = new StringBuilder(); //remark // if (remark != null) { // sb.append("\t/**\n"); // sb.append("\t *" + remark + "\n"); // sb.append("\t */\n"); // } //注解 /*if(useAnnotation){ //自增 if(isAutoincrement){ sb.append("\t@Id\n"); sb.append("\t@Column(name = \"ID\")\n"); sb.append("\t@GeneratedValue(strategy = GenerationType.AUTO)\n"); }else{ sb.append("\t@Column(name = \"" + columnName + "\")\n"); } }*/ // sb.append("\tprivate "); sb.append(dataType + " "); sb.append(name + ";\n"); //get、set sb.append("\tpublic " + dataType + " get" + upperName + "(){\n"); sb.append("\t\treturn " + name + ";\n"); sb.append("\t}\n"); sb.append("\tpublic void set" + upperName + "(" + dataType + " " + name + "){\n"); sb.append("\t\tthis." + name + " = " + name + ";\n"); sb.append("\t}\n"); writeFile(sb.toString(), destPath); } writeFile("}", destPath); } /** * 将ColumnName按照驼峰命名法命名 * @param name * @param firstUpperCase 首字母是否大写 * @return */ public static String formatName(String name, Boolean firstUpperCase){ if(name.indexOf("_") != -1){ String [] split = name.split("_"); String result = ""; for(String str : split){ result += str.toLowerCase().substring(0,1).toUpperCase() + str.toLowerCase().substring(1); } return firstUpperCase ? result : result.substring(0,1).toLowerCase() + result.substring(1); } return firstUpperCase ? name.substring(0,1).toUpperCase() + name.substring(1).toLowerCase() : name.toLowerCase(); } public static void main(String[] args) { File file = new File("myDir"); if (file.exists()) { removedir(file); } if (!file.exists()) { file.mkdir(); } try { List<Object> tables = getAllTableName(); for (Object tblName : tables) { String name = String.valueOf(tblName); String destPath = file.getAbsolutePath()+"\\" + formatName(name, true) + ".java"; //String destPath = "E:\\JAVA测试\\" + formatName(name, true) + ".java"; createEneityClass(PACKAGENAME, name, true, destPath); } } catch (ClassNotFoundException | SQLException | IOException e) { e.printStackTrace(); } } private static void removedir(File file) { File[] files=file.listFiles(); for(File f:files) { if(f.isDirectory())//递归调用 { removedir(f); } else { f.delete(); } } //一层目录下的内容都删除以后，删除掉这个文件夹 file.delete(); } }