提交数据编码问题

nimingdi

POST提交数据：_csrf-frontend=EjdtU4FZNdNsavjw6M6f-1TKLWMASc0wYUOGKvTfVBJqcwwAzSBZvyQcicDauOaNYbMUMTl4mncrJ-l8upklcA%3D%3D&purchase%5Baddr_id%5D=57377&purchase%5Bdef_area%5D=&md5_cart_info=f94b81439dc1ae332e3db291729b4c68&extends_args=%7B&order_type=1&address=667466&shipping=1&payment%5Bcurrency%5D=CNY&payment%5Bpay_app_id%5D=1&payment%5Bfenqi_num%5D=0&invoice_type=%E7%94%B5%E5%AD%90%E5%8F%91%E7%A5%A8&invoice_child_type=%E5%A2%9E%E5%80%BC%E7%A8%8E%E6%99%AE%E9%80%9A%E5%8F%91%E7%A5%A8-%E4%B8%AA%E4%BA%BA&invoice_content=%7B%22invoice_up%22%3A%22%E4%B8%AA%E4%BA%BA%22%2C%22invoice_flag%22%3A%221%22%7D&goods_id=7300&product_id=7763&cart_type=3&coupon=&coupon=&point%5Brate%5D=0.01&point%5Bscore%5D=&memo=&response_json=true

URL解码后数据：_csrf-frontend=EjdtU4FZNdNsavjw6M6f-1TKLWMASc0wYUOGKvTfVBJqcwwAzSBZvyQcicDauOaNYbMUMTl4mncrJ-l8upklcA==&purchase[addr_id]=57377&purchase[def_area]=&md5_cart_info=f94b81439dc1ae332e3db291729b4c68&extends_args={&order_type=1&address=667466&shipping=1&payment[currency]=CNY&payment[pay_app_id]=1&payment[fenqi_num]=0&invoice_type=电子发票&invoice_child_type=增值税普通发票-个人&invoice_content={"invoice_up":"个人","invoice_flag":"1"}&goods_id=7300&product_id=7763&cart_type=3&coupon=&coupon=&point[rate]=0.01&point[score]=&memo=&response_json=true


如何做到只把其中一个字符进行编码，其他维持不变，比如_csrf-frontend的值，只把最后的==编码了，其他又没动，

LEOONL

子文本替换（文本，“==”，“%3D%3D”）