技术学习分享_CKX技术 技术资讯 mysql数据库表映射实体类

mysql数据库表映射实体类

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分享知识 传递快乐

  • JDBC连接数据库;
  • 通过配置文件连接数据库;
  • 反射指定表生成实体类;
  • 反射当前数据库下所有表生成实体类;
  • 类名、属性名、get/set方法名都采用驼峰命名
  • 类名注释、属性注释、方法注释等
package com.xh.activiti.commons.utils;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.Map;
import java.util.Properties;

import org.apache.commons.lang3.StringUtils;

/**
* <p>Title: 获取数据库基本信息的工具类</p>
* <p>Description: </p>
*
* @author H.Yang
* @QQ 1033542070
* @date 2018年3月12日
*/
public class GenEntityTable {

private static final String PROPERTIES_NAME = "config/db.properties";
private static final String PACKAGE_OUT_PATH = "com.xh.activiti.entity";// 指定实体生成所在包的路径
private static final String AUTHOR_NAME = "H.Yang";// 作者名字

private static String tableName = "";// 表名
private static String remarkes = "";// 数据库表注释
private static LinkedList<Map> resultCol = null;// 列信息
private static boolean utilPackage = false; // 是否需要导入包java.util.*
private static boolean sqlPackage = false; // 是否需要导入包java.sql.*
private static Connection connection = null;
private static ResultSet resultSet = null;

public GenEntityTable() {
super();
}

public GenEntityTable(final String driver, final String url, final String name, final String pass) {
try {
Properties props = new Properties();
props.setProperty("user", name);
props.setProperty("password", pass);
props.setProperty("remarks", "true"); // 设置可以获取remarks信息
props.setProperty("useInformationSchema", "true");// 设置可以获取tables remarks信息

// 创建连接
Class.forName(driver);
// getConnection = DriverManager.getConnection(URL, NAME, PASS);
connection = DriverManager.getConnection(url, props);
System.out.println("数据库连接成功");
} catch (ClassNotFoundException | SQLException e) {
System.out.println("数据库驱动加载或连接异常!");
e.printStackTrace();
}
}

/**
* <p>Title: 读取配置文件连接数据库</p>
* <p>Description: </p>
*
* @author H.Yang
* @date 2018年3月12日
*
*/
public static void init() {
try {
Properties properties = new Properties();
InputStream in = GenEntityTable.class.getClassLoader().getResourceAsStream(PROPERTIES_NAME);
properties.load(in);

Properties props = new Properties();
props.setProperty("user", properties.getProperty("db.master.user"));
props.setProperty("password", properties.getProperty("db.master.password"));
props.setProperty("remarks", "true"); // 设置可以获取remarks信息
props.setProperty("useInformationSchema", "true");// 设置可以获取tables remarks信息

// 创建连接
Class.forName(properties.getProperty("db.master.driver"));
connection = DriverManager.getConnection(properties.getProperty("db.master.url"), props);
System.out.println("数据库连接成功");
in.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
}

}

/**
* <p>Title: 获取指定表的基本信息:字段名、字段类型、字段注释</p>
* <p>Description: 自带关闭连接</p>
*
* @author H.Yang
* @date 2018年3月12日
*
*/
private void startTable() {
try {
resultCol = new LinkedList<>();
Map<String, Object> map = null;
resultSet = connection.getMetaData().getTables(null, "%", tableName, new String[] { "TABLE" });
while (resultSet.next()) {
remarkes = resultSet.getString("REMARKS");

ResultSet rs = connection.getMetaData().getColumns(null, "%", resultSet.getString("TABLE_NAME").toUpperCase(), "%");
while (rs.next()) {
map = new HashMap<>();
map.put("columnName", rs.getString("COLUMN_NAME"));
map.put("remarks", rs.getString("REMARKS"));
map.put("dbType", rs.getString("TYPE_NAME"));
map.put("valueType", sqlType2JavaType(rs.getString("TYPE_NAME")));

if (rs.getString("TYPE_NAME").equalsIgnoreCase("datetime")) {
utilPackage = true;
}
if (rs.getString("TYPE_NAME").equalsIgnoreCase("image") || rs.getString("TYPE_NAME").equalsIgnoreCase("text")) {
sqlPackage = true;
}
resultCol.add(map);
}
if (rs != null) {
rs.close();
}
}

// 在内存中生成代码
String content = parse(tableName);
// 写入到文件中
File directory = new File("");
String outputPath = directory.getAbsolutePath() + "/src/main/java/" + PACKAGE_OUT_PATH.replace(".", "/") + "/"
+ initcap(tableName) + ".java";
System.out.println("写出的路径:" + outputPath);
// 创建文件
File file = new File(outputPath);
if (!file.exists()) {
file.createNewFile();
}
// 写出到硬盘
FileWriter fw = new FileWriter(file);
PrintWriter pw = new PrintWriter(fw);
pw.println(content);
pw.flush();
pw.close();
} catch (SQLException | IOException e) {
e.printStackTrace();
} finally {
this.close();
}
}

/**
* <p>Title: 获取当前是数据库下的所有表的基本信息:字段名、字段类型、字段注释</p>
* <p>Description: </p>
*
* @author H.Yang
* @date 2018年3月13日
*
*/
private void startMultitermTable() {
try {
Map<String, Object> map = null;
resultSet = connection.getMetaData().getTables(null, "%", null, new String[] { "TABLE" });
while (resultSet.next()) {
resultCol = new LinkedList<>();
tableName = resultSet.getString("TABLE_NAME");
remarkes = resultSet.getString("REMARKS");
ResultSet rs = connection.getMetaData().getColumns(null, "%", tableName.toUpperCase(), "%");
while (rs.next()) {
map = new HashMap<>();
map.put("columnName", rs.getString("COLUMN_NAME"));
map.put("remarks", rs.getString("REMARKS"));
map.put("dbType", rs.getString("TYPE_NAME"));
map.put("valueType", sqlType2JavaType(rs.getString("TYPE_NAME")));

if (rs.getString("TYPE_NAME").equalsIgnoreCase("datetime")) {
utilPackage = true;
}
if (rs.getString("TYPE_NAME").equalsIgnoreCase("image") || rs.getString("TYPE_NAME").equalsIgnoreCase("text")) {
sqlPackage = true;
}
resultCol.add(map);
}
if (rs != null) {
rs.close();
}

// 在内存中生成代码
String content = parse(transVar(tableName));
// 写入到文件中
File directory = new File("");
String outputPath = directory.getAbsolutePath() + "/src/main/java/" + PACKAGE_OUT_PATH.replace(".", "/") + "/"
+ transVar(tableName) + ".java";
System.out.println("写出的路径:" + outputPath);
// 创建文件
File file = new File(outputPath);
if (!file.exists()) {
file.createNewFile();
}
// 写出到硬盘
FileWriter fw = new FileWriter(file);
PrintWriter pw = new PrintWriter(fw);
pw.println(content);
pw.flush();
pw.close();
}

} catch (SQLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
this.close();
}
}

/**
* <p>Title: 关闭数据库连接</p>
* <p>Description: </p>
*
* @author H.Yang
* @date 2018年3月12日
*
*/
private static void close() {
try {
if (resultSet != null) {
resultSet.close();
}
if (connection != null) {
connection.close();
}
System.out.println("数据库连接关闭");
} catch (SQLException e) {
e.printStackTrace();
}
}

/**
* 功能:生成实体类主体代码
* @param colNames
* @param colTypes
* @param colSizes
* @return
*/
private String parse(String tablename) {
StringBuffer sb = new StringBuffer();
sb.append("package " + PACKAGE_OUT_PATH + ";rn");
sb.append("rn");
// 判断是否导入工具包
if (utilPackage) {
sb.append("import java.util.Date;rn");
}
if (sqlPackage) {
sb.append("import java.sql.*;rn");
}
// 注释部分
sb.append("rn");
sb.append("/**rn");
sb.append(" * <p>Title: " + remarkes + "</p>rn");
sb.append(" * <p>Description: </p>rn");
sb.append(" * rn");
sb.append(" * @author " + AUTHOR_NAME + "rn");
sb.append(" * @QQ 1033542070rn");
sb.append(" * rn");
sb.append(" * @date " + new SimpleDateFormat("yyyy-MM-dd").format(new Date()) + "rn");
sb.append(" */ rn");
// 实体部分
sb.append("public class " + tablename + "{rn");
processAllAttrs(sb);// 属性
processAllMethod(sb);// get set方法
sb.append("}");

return sb.toString();
}

/**
* <p>Title: 生成所有属性 </p>
* <p>Description: </p>
*
* @author H.Yang
* @date 2018年3月12日
*
* @param sb
*/
private void processAllAttrs(StringBuffer sb) {
// 列名集合
for (Map<String, String> mapAttr : resultCol) {
if (StringUtils.isNotBlank(mapAttr.get("remarks"))) {
sb.append("t// " + mapAttr.get("remarks") + "rn");
}
sb.append("tprivate " + mapAttr.get("valueType") + " " + defineVar(mapAttr.get("columnName")) + ";rn");
}
}

/**
* <p>Title: 生成所有方法 </p>
* <p>Description: </p>
*
* @author H.Yang
* @date 2018年3月12日
*
* @param sb
*/
private void processAllMethod(StringBuffer sb) {

for (Map<String, String> mapMethod : resultCol) {
// SET
sb.append("rn");
if (StringUtils.isNotBlank(mapMethod.get("remarks"))) {
sb.append("t/**rn");
sb.append("t * " + mapMethod.get("remarks") + "rn");
sb.append("t */rn");
}
sb.append("tpublic void set" + transVar(mapMethod.get("columnName")) + "(" + mapMethod.get("valueType") + " "
+ defineVar(mapMethod.get("columnName")) + ") {rn");
sb.append("ttthis." + defineVar(mapMethod.get("columnName")) + " = " + defineVar(mapMethod.get("columnName")) + ";rn");
sb.append("t}rn");

// GET
sb.append("rn");
if (StringUtils.isNotBlank(mapMethod.get("remarks"))) {
sb.append("t/**rn");
sb.append("t * " + mapMethod.get("remarks") + "rn");
sb.append("t */rn");
}
sb.append("tpublic " + mapMethod.get("valueType") + " get" + initcap(transVar(mapMethod.get("columnName"))) + "() {rn");
sb.append("ttreturn " + defineVar(mapMethod.get("columnName")) + ";rn");
sb.append("t}rn");
}
}

/**
* <p>Title: 将输入字符串的首字母改成大写</p>
* <p>Description: </p>
*
* @author H.Yang
* @date 2018年3月12日
*
* @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);
}

/**
* <p>Title: 用于生成get/set方法时 </p>
* <p>Description: 第一个字母大写,“_”后面一个字母大写,并去掉“_”</p>
*
* @author H.Yang
* @date 2018年3月12日
*
* @param str
* @return
*/
private String transVar(String str) {
StringBuffer sb = new StringBuffer(str.toLowerCase());
String sign = "_";
int index = 0;
while ((index = sb.indexOf(sign, index)) != -1) {
sb.replace(index, (index + sign.length()), "");

char[] ch = new String(sb).toCharArray();
if (ch[0] >= 'a' && ch[0] <= 'z') {
ch[0] = (char) (ch[0] - 32);
}
if (index != 0 && index != ch.length) {
ch[index] = (char) (ch[index] - 32);
}
sb = new StringBuffer(new String(ch));
index = index + sign.length();
}
return sb.toString();
}

/**
* <p>Title: 用于定义变量名 </p>
* <p>Description: 首字母小写,“_”后面一个字母大写,并去掉“_”</p>
*
* @author H.Yang
* @date 2018年3月12日
*
* @param str
* @return
*/
private String defineVar(String str) {
StringBuffer sb = new StringBuffer(str.toLowerCase());
String sign = "_";
int index = 0;
while ((index = sb.indexOf(sign, index)) != -1) {
sb.replace(index, (index + sign.length()), "");
char[] ch = new String(sb).toCharArray();
if (ch[0] >= 'a' && ch[0] <= 'z' && index == 0) {
ch[0] = (char) (ch[0] - 32);
}
if (index != 0 && index != ch.length) {
ch[index] = (char) (ch[index] - 32);
}
sb = new StringBuffer(new String(ch));
index = index + sign.length();
}
return sb.toString();
}

/**
* <p>Title: 获得列的数据类型 </p>
* <p>Description: </p>
*
* @author H.Yang
* @date 2018年3月12日
*
* @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 unsigned")) {
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) {

// GenEntityTable entity = new GenEntityTable("com.mysql.jdbc.Driver",
// "jdbc:mysql://localhost:3306/springwind?useUnicode=true&characterEncoding=utf-8", "root", "admini");
GenEntityTable entity = new GenEntityTable();
entity.init();
entity.startMultitermTable();
// entity.startTable();

}
}

 

关于​​DatabaseMetaData的用法​​ 

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作者: CKX技术

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