Java 结果集转换为 JSON。如何打印 json 对象？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/9686732/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
resultset into JSON. How can I print the json Object?
提问by Becks
I am referring to this linkbut I have slightly modified my approach..
我指的是这个链接，但我稍微修改了我的方法..
This is the code that I have :
这是我拥有的代码：
public JSONArray generateJSON(ResultSet rs) {
JSONArray respJSON = new JSONArray();
try {
java.sql.ResultSetMetaData rsmd = rs.getMetaData();
int numColumns = rsmd.getColumnCount();
while (rs.next()) {
JSONObject obj = new JSONObject();
for (int i = 1; i < numColumns + 1; i++) {
String columnName = rsmd.getColumnName(i);
if (rsmd.getColumnType(i) == java.sql.Types.ARRAY) {
obj.put(columnName, rs.getArray(i));
} else if (rsmd.getColumnType(i) == java.sql.Types.BIGINT) {
obj.put(columnName, rs.getInt(i));
} else if (rsmd.getColumnType(i) == java.sql.Types.BOOLEAN) {
obj.put(columnName, rs.getBoolean(i));
} else if (rsmd.getColumnType(i) == java.sql.Types.BLOB) {
obj.put(columnName, rs.getBlob(i));
} else if (rsmd.getColumnType(i) == java.sql.Types.DOUBLE) {
obj.put(columnName, rs.getDouble(i));
} else if (rsmd.getColumnType(i) == java.sql.Types.FLOAT) {
obj.put(columnName, rs.getFloat(i));
} else if (rsmd.getColumnType(i) == java.sql.Types.INTEGER) {
obj.put(columnName, rs.getInt(i));
} else if (rsmd.getColumnType(i) == java.sql.Types.NVARCHAR) {
obj.put(columnName, rs.getNString(i));
} else if (rsmd.getColumnType(i) == java.sql.Types.VARCHAR) {
obj.put(columnName, rs.getString(i));
} else if (rsmd.getColumnType(i) == java.sql.Types.TINYINT) {
obj.put(columnName, rs.getInt(i));
} else if (rsmd.getColumnType(i) == java.sql.Types.SMALLINT) {
obj.put(columnName, rs.getInt(i));
} else if (rsmd.getColumnType(i) == java.sql.Types.DATE) {
obj.put(columnName, rs.getDate(i));
} else if (rsmd.getColumnType(i) == java.sql.Types.TIMESTAMP) {
obj.put(columnName, rs.getTimestamp(i));
} else {
obj.put(columnName, rs.getObject(i));
}
}
respJSON.put(obj);
//respJSON.add(obj);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
respJSON.toString();
return respJSON;
System.out.print(respJSON.toString());
}
My problem is that I can not print the json string to see it in the console ...
我的问题是我无法打印 json 字符串以在控制台中查看它...
I have tried the respJSON.toString(); and it doesnt seem to work ..
我试过 respJSON.toString(); 它似乎不起作用..
Could you please help me ? ...
请你帮助我好吗 ？...
Thank you
谢谢
采纳答案by Muhammad Saifuddin
Your program cannot reach to the printstatement as there is a returnstatement before that. If you had been using an IDE like Netbeansor Eclipse, that would have given you a clear warning.
您的程序无法访问该print语句，因为return在此之前有一个语句。如果您一直在使用 IDE 之类的Netbeans或Eclipse，那会给您一个明确的警告。
回答by bpgergo
this is a simple typo. instead of this:
这是一个简单的错字。而不是这个：
respJSON.toString();
return respJSON;
System.out.print(respJSON.toString());
do this
做这个
System.out.print(respJSON.toString());
return respJSON;
