请考虑我们有String
String Description="{"DN":"Systems and Software Verification: Model-Checking Techniques and Tools","D":"Model checking is a powerful approach for the formal verification of software. It automatically provides complete proofs of correctness, or explains, via counter-examples, why a system is not correct. Here, the author provides a well written and basic introduction to the new technique. The first part describes in simple terms the theoretical basis of model checking: transition systems as a formal model of systems, temporal logic as a formal language for behavioral properties, and model-checking algorithms. The second part explains how to write rich and structured temporal logic specifications in practice, while the third part surveys some of the major model checkers available.","S":[{"Ty":1,"U":"http://dl.acm.org/citation.cfm?id=1965314"},{"Ty":1,"U":"http://ci.nii.ac.jp/ncid/BA52610493"}]}";
我想要做的是提取这个字符串：
"Model checking is a powerful approach for the formal verification of software. It automatically provides complete proofs of correctness, or explains, via counter-examples, why a system is not correct. Here, the author provides a well written and basic introduction to the new technique. The first part describes in simple terms the theoretical basis of model checking: transition systems as a formal model of systems, temporal logic as a formal language for behavioral properties, and model-checking algorithms. The second part explains how to write rich and structured temporal logic specifications in practice, while the third part surveys some of the major model checkers available."
使用：
String text=Description.split("D"+":").toString();
不起作用，即使这样，在没有必要的文本之后也会出现无用的字符。怎么办？