JDBC读取数据库元数据,生成JAVA实体类

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JDBC读取数据库元数据,生成JAVA实体类
package com.nffish.util;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import com.nffish.common.DBSession;
public class GenEntityTool {
private String tablename = "petDiary";
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.*
public GenEntityTool() {
Connection conn = DBSession.getConnection(); // 得到数据库连接
String strsql = "select * from " + tablename;
try {
PreparedStatement pstmt = conn.prepareStatement(strsql);
ResultSetMetaData rsmd = pstmt.getMetaData();
int size = rsmd.getColumnCount(); // 共有多少列
colnames = new String[size];
colTypes = new String[size];
colSizes = new int[size];
for (int i = 0; i < rsmd.getColumnCount(); 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 {
FileWriter fw = new FileWriter(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 {
DBSession.closeConnection(conn);
}
}
/**
* 解析处理(生成实体类主体代码)
*/
private String parse(String[] colNames, String[] colTypes, int[] colSizes) {
StringBuffer sb = new StringBuffer();
if (f_util) {
sb.append("import java.util.Date;/r/n");
}
if (f_sql) {
sb.append("import java.sql.*;/r/n/r/n/r/n");
}
sb.append("public class " + initcap(tablename) + " {/r/n");
processAllAttrs(sb);
processAllMethod(sb);
sb.append("}/r/n");
System.out.println(sb.toString());
return sb.toString();
}
/**
* 生成所有的方法
*
* @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("/t/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");
}
}
/**
* 解析输出属性
*
* @return
*/
private void processAllAttrs(StringBuffer sb) {
for (int i = 0; i < colnames.length; i++) {
sb.append("/tprivate " + sqlType2JavaType(colTypes[i]) + " "
+ colnames[i] + ";/r/n");
}
}
/**
* 把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);
}
private String sqlType2JavaType(String sqlType) {
if (sqlType.equalsIgnoreCase("bit")) {
return "bool";
} 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")) {
return "double";
} else if (sqlType.equalsIgnoreCase("money")
|| sqlType.equalsIgnoreCase("smallmoney")) {
return "double";
} else if (sqlType.equalsIgnoreCase("varchar")
|| sqlType.equalsIgnoreCase("char")
|| sqlType.equalsIgnoreCase("nvarchar")
|| sqlType.equalsIgnoreCase("nchar")) {
return "String";
} else if (sqlType.equalsIgnoreCase("datetime")) {
return "Date";
}
else if (sqlType.equalsIgnoreCase("image")) {
return "Blob";
} else if (sqlType.equalsIgnoreCase("text")) {
return "Clob";
}
return null;
}
public static void main(String[] args) {
new GenEntityTool();
}
}