java 从数据库表反射出实体类，自动生成实体类
package com.soft.ms.test;
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.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Date;
/**
* 根据数据库表结构生成相应的JavaBean
*
* 思路
* 1、创建数据库连接
* 2、获取数据库表、表注释
* 3、获取数据库表中字段名、字段类型、字段注释
* 4、构建StringBuffer缓存
* 5、写入文件
* 6、关闭连接、输入流等等
*
* @author ella_li
*
*/
public class GenEntityOracle {
private String packageOutPath = "com.soft.ms.test";// 指定实体生成所在包的路径
private String authorName = "ella_li";// 作者名字
private String[] tableNames;
private String[] tablePre = { "TB_" };
private String[] colsPre = { "F_NB_", "F_VC_", "F_CR_", "F_DT_"};
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:oracle:thin:@192.168.0.114:1521:oracle";
private static final String NAME = "ms";
private static final String PASS = "ms";
private static final String DRIVER = "oracle.jdbc.driver.OracleDriver";
private Connection con = null;
private Statement pStemt = null;
private ResultSet rs = null;
private ResultSetMetaData rsmd = null;
public GenEntityOracle() {
connect();
getAllTables();
}
/**
* 1、创建数据库连接
*/
private void connect() {
try {
Class.forName(DRIVER);
con = DriverManager.getConnection(URL, NAME, PASS);
pStemt = (Statement) con.createStatement();
} catch (ClassNotFoundException | SQLException e) {
e.printStackTrace();
}
}
private void colseConnect() {
try {
if (con != null) {
con.close();
con = null;
}
if (pStemt != null) {
pStemt.close();
pStemt = null;
}
} catch (SQLException e) {
e.printStackTrace();
}
}
/**
* 获取所有表名
*/
private void getAllTables() {
String sql = "SELECT TABLE_NAME FROM USER_TABLES";
try {
rs = pStemt.executeQuery(sql);
String s = "";
while (rs.next()) {
s = s + rs.getString("TABLE_NAME") + ",";
}
tableNames = s.substring(0,s.length()-1).split(",");
for (String tableName : tableNames) {
getTableInfo(tableName);
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
colseConnect();
}
}
/**
* 获取单个数据库表信息
*/
private void getTableInfo(String tableName) {
int size = 0;
String sql = "SELECT * FROM " + tableName;
try {
rs = pStemt.executeQuery(sql);
rsmd = rs.getMetaData();
size = rsmd.getColumnCount();
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("date")
|| colTypes[i].equalsIgnoreCase("timestamp")) {
f_util = true;
}
if (colTypes[i].equalsIgnoreCase("blob")
|| colTypes[i].equalsIgnoreCase("char")) {
f_sql = true;
}
colSizes[i] = rsmd.getColumnDisplaySize(i + 1);
}
//规范化表名
String normTableName = normTableName(tableName);
//获取单张数据库表注释
String tableComment = getTableComment(tableName);
//获取单张数据库表的所有列信息
StringBuffer tempSb = getColsInfo(tableName);
//生成JavaBean文件
genFile(normTableName, getSb(normTableName, tableComment, tempSb));
} catch (SQLException e) {
e.printStackTrace();
}
}
/**
* 规范类名
*
* @param tableName
* @return
*/
public String normTableName(String tableName) {
String result = "";
for (String temp : tablePre) {
int index = tableName.indexOf(temp);
if (index >= 0) {
tableName = tableName.substring(index + temp.length());
String[] names = tableName.split("_");
if (null != names && names.length > 0) {
for (String name : names) {
result += captureName(name.toLowerCase());
}
}
}
}
return result;
}
/**
* 获取单张数据库表注释
*
* @param tableName
* @return
*/
private String getTableComment(String tableName) {
String str = "";
String sql = "select * from user_tab_comments where table_name = '"
+ tableName + "'";
try {
rs = pStemt.executeQuery(sql);
while (rs.next()) {
str = rs.getString("comments");
if (null != str && str.indexOf("\r\n") != -1) {
str = str.replace("\r\n", "");
}
if (null != str && str.indexOf("\n") != -1) {
str = str.replace("\n", "");
}
}
} catch (SQLException e) {
e.printStackTrace();
}
return str;
}
/**
* 获取单张数据库表的所有列信息
*
* @param tableName
*/
private StringBuffer getColsInfo(String tableName) {
StringBuffer temp = new StringBuffer();
for (int i = 0; i < colnames.length; i++) {
temp.append("\tprivate " + getColsType(colTypes[i]) + " "
+ getColsName(colnames[i]) + "; //"
+ getColComment(tableName, colnames[i]) + "\r\n");
String colname = getColsName(colnames[i]);
String colnameUp = captureName(colname);
temp.append("\n\tpublic void set" + colnameUp + "("
+ getColsType(colTypes[i]) + " " + colname + "){\r\n");
temp.append("\t\tthis." + colname + "=" + colname + ";\r\n");
temp.append("\t}\r\n");
temp.append("\n\tpublic " + getColsType(colTypes[i]) + " get"
+ colnameUp + "(){\r\n");
temp.append("\t\treturn " + colname + ";\r\n");
temp.append("\t}\r\n");
}
return temp;
}
/**
* 获取列类型
*
* @param sqlType
* @return
*/
private String getColsType(String sqlType) {
if (sqlType.equalsIgnoreCase("binary_double")) {
return "double";
} else if (sqlType.equalsIgnoreCase("binary_float")) {
return "float";
} else if (sqlType.equalsIgnoreCase("blob")) {
return "byte[]";
} else if (sqlType.equalsIgnoreCase("blob")) {
return "byte[]";
} else if (sqlType.equalsIgnoreCase("char")
|| sqlType.equalsIgnoreCase("nvarchar2")
|| sqlType.equalsIgnoreCase("varchar2")) {
return "String";
} else if (sqlType.equalsIgnoreCase("date")
|| sqlType.equalsIgnoreCase("timestamp")
|| sqlType.equalsIgnoreCase("timestamp with local time zone")
|| sqlType.equalsIgnoreCase("timestamp with time zone")) {
return "Date";
} else if (sqlType.equalsIgnoreCase("number")) {
return "Long";
}
return "String";
}
/**
* 获取列名
*
* @param str
* @return
*/
private String getColsName(String str) {
for (String temp : colsPre) {
int preIndex = str.indexOf(temp);
if (preIndex >= 0) {
str = str.substring(preIndex + temp.length());
str = str.replace("_", "").toLowerCase();
}
}
return str;
}
/**
* 获取列注释
*
* @param tableName
* @param columnName
* @return
*/
private String getColComment(String tableName, String columnName) {
String str = "";
String sql = "select comments from USER_COL_COMMENTS where table_name= '"
+ tableName + "' and column_name= '" + columnName + "'";
try {
rs = pStemt.executeQuery(sql);
while (rs.next()) {
str = rs.getString("comments");
if (null != str && str.indexOf("\r\n") != -1) {
str = str.replace("\r\n", "");
}
if (null != str && str.indexOf("\n") != -1) {
str = str.replace("\n", "");
}
}
} catch (SQLException e) {
e.printStackTrace();
}
return str;
}
/**
* 构建StringBuffer缓存
*
* @param tableName
* @param tableComment
* @param colSb
* @return
*/
private StringBuffer getSb(String tableName, String tableComment,
StringBuffer colSb) {
StringBuffer sb = new StringBuffer();
sb.append("package " + this.packageOutPath + ";\r\n");
// 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("\r\n");
// 注释部分
sb.append(" /**\r\n");
sb.append(" * " + tableName + " 实体类 " + tableComment + "\r\n");
sb.append(" * " + new Date() + "\r\n");
sb.append(" * @author " + this.authorName + "\r\n");
sb.append(" */ \r\n");
// 实体部分
sb.append("\r\n\r\npublic class " + tableName + "{\r\n");
sb.append("\tprivate static final long serialVersionUID = 1L;\r\n");
sb.append(colSb);
sb.append("}\r\n");
return sb;
}
/**
* 生成JavaBean文件
*
* @param content
*/
private void genFile(String tableName, StringBuffer content) {
try {
File directory = new File("");
String outputPath = directory.getAbsolutePath() + "/src/"
+ this.packageOutPath.replace(".", "/") + "/" + tableName
+ ".java";
FileWriter fw = new FileWriter(outputPath);
PrintWriter pw = new PrintWriter(fw);
pw.println(content);
pw.flush();
pw.close();
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* 首字母大写
* @param name
* @return
*/
public static String captureName(String name) {
char[] cs = name.toCharArray();
cs[0] -= 32;
return String.valueOf(cs);
}
/**
* 出口 TODO
*
* @param args
*/
public static void main(String[] args) {
new GenEntityOracle();
}
}
查询数据库里所有表名和字段名的语句
SQL 查询所有表名：
SELECT NAME FROM SYSOBJECTS WHERE TYPE='U'
SELECT * FROM INFORMATION_SCHEMA.TABLES
查询表的所有字段名：
SELECT NAME FROM SYSCOLUMNS WHERE ID=OBJECT_ID(' 表名' )
SELECT * FROM INFORMATION_SCHEMA.TABLES
SELECT * FROM INFORMATION_SCHEMA.VIEWS
SELECT * FROM INFORMATION_SCHEMA.COLUMNS
ORACLE 查看所有表名:
SELECT TABLE_NAME FROM USER_TABLES
ACCESS 查看所有表名：
SELECT NAME FROM MSYSOBJECTS WHERE TYPE=1 AND FLAGS=0
MSYSOBJECTS 是系统对象，默认情况是隐藏的。通过工具、选项、视图、显示、系统对象可以使之显示出来。
